Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Effect of Brief Biofeedback via a Smartphone App on Stress Recovery: Randomized Experimental Study

Effect of Brief Biofeedback via a Smartphone App on Stress Recovery: Randomized Experimental Study Background: Smartphones are often vilified for negatively influencing well-being and contributing to stress. However, these devices may, in fact, be useful in times of stress and, in particular, aid in stress recovery. Mobile apps that deliver evidence-based techniques for stress reduction, such as heart rate variability biofeedback (HRVB) training, hold promise as convenient, accessible, and effective stress-reducing tools. Numerous mobile health apps that may potentially aid in stress recovery are available, but very few have demonstrated that they can influence health-related physiological stress parameters (eg, salivary biomarkers of stress). The ability to recover swiftly from stress and reduce physiological arousal is particularly important for long-term health, and thus, it is imperative that evidence is provided to demonstrate the effectiveness of stress-reducing mobile health apps in this context. Objective: The purpose of this research was to investigate the physiological and psychological effects of using a smartphone app for HRVB training following a stressful experience. The efficacy of the gamified Breather component of the Happify mobile health app was examined in an experimental setting. Methods: In this study, participants (N=140) underwent a laboratory stressor and were randomly assigned to recover in one of three ways: with no phone present, with a phone present, with the HRBV game. Those in the no phone condition had no access to their phone. Those in the phone present condition had their phone but did not use it. Those in the HRVB game condition used the serious game Breather on the Happify app. Stress recovery was assessed via repeated measures of salivary alpha amylase, cortisol, and self-reported acute stress (on a 1-100 scale). Results: Participants in the HRVB game condition had significantly lower levels of salivary alpha amylase during recovery than participants in the other conditions (F =3.78, P=.03). There were no significant differences among the conditions during 2,133 recovery for salivary cortisol levels or self-reported stress. Conclusions: These results show that engaging in a brief HRVB training session on a smartphone reduces levels of salivary alpha amylase following a stressful experience, providing preliminary evidence for the effectiveness of Breather in improving physiological stress recovery. Given the known ties between stress recovery and future well-being, this study provides a possible mechanism by which gamified biofeedback apps may lead to better health. (JMIR Serious Games 2019;7(4):e15974) doi: 10.2196/15974 KEYWORDS heart rate variability biofeedback; stress recovery; salivary alpha amylase; smartphone; mHealth http://games.jmir.org/2019/4/e15974/ JMIR Serious Games 2019 | vol. 7 | iss. 4 | e15974 | p. 1 (page number not for citation purposes) XSL FO RenderX JMIR SERIOUS GAMES Hunter et al beneficial for stress recovery. In fact, when looked at more Introduction broadly, greater use of smartphones is associated with higher levels of physiological stress [21]. Therefore, if we hope to Background highlight the most effective ways to use a phone to reduce stress, Although smartphones are often criticized for contributing to it may be important to go beyond natural phone use habits and, ill-being [1-4], these devices hold great potential for improving instead, provide structured apps that are specifically designed one’s well-being if utilized properly in specific contexts. for stress reduction. Smartphones may be particularly useful as tools that provide One promising way to use a smartphone to aid in stress reduction gamified apps to deliver stress-buffering interventions. Stress is by engaging with a mobile health (mHealth) app. mHealth is prevalent in many peoples’ lives, and its accumulated effects apps can utilize technological capabilities (eg, phone sensors, can lead to various undesirable physical and mental health interactive displays) and draw on the ubiquity of smartphones outcomes, such as an increased risk for mortality [5]. Many of in everyday life to deliver functional and convenient these negative outcomes are due to prolonged activation of one’s interventions [22]. By combining evidence-based stress systems [6]. However, if individuals employ strategies stress-reduction techniques with an engaging and ever-present that promote more efficient recovery from stressors, some of medium, mHealth apps hold great promise for mitigating the the negative long-term impacts may be mitigated. negative effects of stress. Why do smartphones present a promising opportunity for Happify is an mHealth app that provides gamified activities altering stress recovery? Psychologists have developed a variety aimed at improving well-being and reducing stress [23]. Happify of evidence-backed strategies that aid in stress reduction [7], is representative of multiple aspects of other mHealth apps such as biofeedback training, which directs individuals to because it employs various smartphone technological monitor and attempt to alter their physiological arousal pattern capabilities (eg, sensors, visual and audio components, engaging [8]. Smartphones are ideally situated to be used as a tool for interface) and incorporates empirically validated strategies to biofeedback training and to combat the negative effects of stress deliver training in a self-contained package. Within the Happify because they are popular, conveniently accessible, and have an suite of activities, the Breather function delivers heart rate array of technological capabilities [9]. Since these devices are variability biofeedback (HRVB) training (Multimedia Appendix nearly omnipresent in daily life, they can deliver interventions 1). HRVB is a particularly effective stress-reducing activity that and assistance wherever and whenever needed. targets changes in heart rate variability (HRV) by regulating Smartphones provide a range of possibilities for helping breathing and bringing awareness to physiological function individuals recover from a stressful experience and may even [24]. HRV is an index of beat-to-beat changes in heart rate and do so when not actively used. Even when merely present, is an indicator of parasympathetic nervous system activity [25]. smartphones serve as symbols that can cause cognitive When undergoing a stressor, the typical response is for our distraction [10] or activate representations of social connections sympathetic nervous system to activate and parasympathetic [11]. Distraction induced by smartphones has generally been activity to decline (indicating low HRV). However, an adaptive viewed as detrimental [12]; however, such distraction can be response to a stressor would be for an individual to exhibit beneficial when faced with a stressor, because it can draw higher HRV. This is because greater fluctuations in heart rhythm attention away from the negative stimuli at hand and help (higher HRV) indicate greater adaptability to physiological circumvent rumination [13]. In addition, symbolic needs than fewer fluctuations (lower HRV) [24]. When HRV representations of social connections can elicit perceptions of is higher, it is a sign that our cardiovascular system (and multiple social support [14], which, when perceived passively, is the associated systems) is responding appropriately to environmental most effective form of support for stress alleviation [15]. By demands (eg, a stressor). Thus, using HRVB to increase HRV providing distraction and perceived social support, the mere may be helpful when recovering from a stressor because it presence of a smartphone may aid in stress recovery by serving activates our parasympathetic nervous system and allows us to as a “digital security blanket” in instances of social stress [16]. more quickly reduce physiological arousal. It is also important Thus, it is important to investigate more fully how merely having to note that high HRV is considered a protective factor against a smartphone in one’s presence may aid in stress alleviation. cardiovascular disease and is generally associated with good health and well-being [26]. Additionally, low HRV has Research has demonstrated that actually using one’s smartphone numerous negative implications for long-term health outcomes, can be beneficial or detrimental for stress recovery, depending such as increased risk for mortality and morbidity [27,28]. on how and when the device is used. For example, research has HRVB training has been successfully utilized in a variety of shown that using social media sites such as Facebook can acute stress settings and is well-validated technique for reducing provide social resources that sometimes help buffer acute stress stress [29,30]. The goal of undergoing a 5-minute guided session [17], but at other times, fail to do so [18]. In some instances, on Breather is for the user to increase HRV and recover social support gleaned via text message can reduce effectively from a stressful experience. cardiovascular responses to stress [19]. However, sending and receiving text messages can also increase physiological Delivering HRVB through a smartphone app provides many indicators of stress such as heart rate, respiration, and skin advantages over traditional training. Breather overcomes barriers conductance [20]. These mixed findings concerning how phone of nondigital HRVB interventions (eg, bulky and expensive use influences stress underscore the fact that the ways in which equipment, lengthy sessions) because it is quick to administer, we commonly interact with our devices are not universally is portable and readily accessible, and has all the hardware and http://games.jmir.org/2019/4/e15974/ JMIR Serious Games 2019 | vol. 7 | iss. 4 | e15974 | p. 2 (page number not for citation purposes) XSL FO RenderX JMIR SERIOUS GAMES Hunter et al software integrated into a single device. Breather has taken (Figure 1B). The meter directs the individual to breathe in for advantage of mobile technology affordances to package an 4 seconds and then breathe out for 6 seconds. This 10-second HRVB product in ways that should allow it to be used across a breathing cycle is ideal for creating a resonant frequency (ie, variety of stressful contexts. breathing and heart rate align) that should maximize HRV [32]. Users of Breather generate HRV observations by placing their After calibration is complete, the interface changes into a index finger over the camera of their smartphone (Figure 1A). calming nature scene (eg, underwater coral bed, tropical beach, The light from the camera can be used to monitor blood volume mountaintops). The user then travels through the natural changes within the finger. This process (ie, environment while he/she continues to breathe along with the photoplethysmography) relies on measuring changes in light meter (Figure 2A). As they breathe deeply and regularly, their absorption on the skin of the finger. Algorithms programmed HRV increases and the scene becomes more complex and by Happify software engineers then transform those data into beautiful (eg, coral polyps bloom, flowers grow; Figure 2B). a simple signal that is visible to the user. The accuracy of this By visually monitoring the changes in the scene, individuals technology for determining HRV has been recently validated are undergoing HRVB; this process is analogous to how in a series of experiments that compared simultaneously individuals monitor electrocardiogram signals in more traditional obtained HRV metrics from Happify Breather and traditional “nongamified” HRVB trainings. The app is designed to increase electrocardiogram techniques using electrodes [31]. HRV and reduce stress if the users adhere to the directions properly for a 5-minute session. After calibrating the heart rate of the individual, a circular meter directs the individual to follow the breathing patterns on screen Figure 1. On-screen instructions for obtaining heart rate variability measurement and calibrating breathing guidance. Figure 2. Example of how the full display unfolds when an individual is using Breather. multimodal approach that combines subjective and objective Assessment of Stress assessments [34]. In this paper, we used a multimethodological approach to One of the most effective, reliable, and efficient ways to capture determine the effects of smartphones on stress recovery. Stress physiological measurements of stress is to analyze salivary can be assessed in a variety of ways, and each method provides biomarkers. Salivary cortisol is a downstream output of unique insight into the complex dynamics of how stress impacts hypothalamic-pituitary-adrenal axis system activation and is our bodies and brains. One of the most common ways to assess one of the most widely used and reliable measures of stress is to ask individuals to subjectively rate their stress level. physiological stress [35]. Higher levels of salivary cortisol Although self-report is advantageous for assessing perceived indicate greater physiological stress. Another emerging indicator stress, there are problems of bias (eg, self-presentation concerns) of physiological stress is salivary alpha amylase (sAA), which that limit the accuracy and generalizability of these assessments is an indicator of autonomic nervous system activity and is most [33]. Due to its complexity, the most appropriate and strongly tied with sympathetic nervous system activity, the comprehensive manner in which stress is assessed is a system responsible for the “fight-or-flight” response [36]. When http://games.jmir.org/2019/4/e15974/ JMIR Serious Games 2019 | vol. 7 | iss. 4 | e15974 | p. 3 (page number not for citation purposes) XSL FO RenderX JMIR SERIOUS GAMES Hunter et al physiologically aroused, sAA is released via the salivary glands were not fluent in English, or did not have an iPhone. All and indicates an immediate stress response. In some cases, sAA participants were University of California, Irvine, students and is more strongly tied to stress and anxiety than cortisol [37,38], consented to participate. Data collection took place from July and sAA (but not cortisol) has also been shown to be influenced 2018 through February 2019. by smartphones while recovering from a stressor [16]. Thus, Procedures sAA is considered our primary outcome of interest. These Participants underwent an approximately 90-minute laboratory salivary assessments of hypothalamic-pituitary-adrenal and session. All participant phones were confiscated at the beginning autonomic nervous system activities combined with self-report of the study under the pretext of measuring the external physical give researchers a comprehensive understanding of physiological properties of the phone, which allowed the experimenter to later responses to stress. manipulate the phone conditions without arousing suspicion This Study and ensure that all participants experienced similar This study investigated the effectiveness of using an HRVB circumstances of having their phone taken away. For participants smartphone app to aid in stress recovery. In order to account randomly assigned to the HRVB game condition, the Happify for the potential stress-buffering effects of simply having a app was installed on their phone and the experimenter guided phone [16], we included a condition in which individuals had them through the calibration settings of the Breather function a phone in their presence. Thus, use of the HRVB app was while carefully concealing any indication that the purpose of compared to two control conditions, one in which no phone was using Breather was to reduce stress. Participants in the other present and one in which individuals had their smartphones conditions filled out surveys during this time. After participants present when recovering from a stressor. completed a series of questionnaires and acclimated to the laboratory environment (approximately 25 minutes), the To examine how these different types of smartphone interactions experimenter returned to the laboratory room and collected a influence stress recovery, a laboratory experiment was baseline saliva sample. Participants were instructed in the conducted in which participants underwent a standardized passive drool technique of collecting their own saliva sample. stressor, used their phone in a particular way depending on their assigned condition, and were assessed on a range of Participants then underwent a shortened version of the Trier psychological and physiological stress indicators. We Social Stress Task (TSST) [40,41] to induce psychological and hypothesized that those in the HRVB game condition would physiological stress. The TSST consists of participants recover from the stressor more effectively than those who had undergoing a public speaking task and arithmetic task in front their phones present or had no phone at all. of a panel of critically evaluative judges. The TSST has been shown to be a valid and reliable instrument for inducing This study is one of the first empirical investigations to assess physiological and psychological stress responses [42]. the effects of smartphone app usage on salivary biomarkers of Immediately after the conclusion of the TSST, participants physiological stress [39]. To our knowledge, it is also the first collected another saliva sample and self-reported their feelings to examine the stress-buffering effects of an HRVB intervention of stress. For the next 5 minutes, participants were left alone in delivered via a smartphone without any external equipment. In the room and interacted with their phone in a particular way addition, since simply having a phone in your presence has been depending on condition. Those in the no phone condition did shown to aid in stress recovery, the inclusion of separate not have their phone returned and were told to sit quietly for experimental conditions for a HRVB game and mere phone the next 5 minutes while the next portion of the study was presence enabled us to differentiate their effects on stress. The prepared. Those in the phone present condition were given their results of this study will help our understanding of why phone but told “please do not use your phone for the remainder smartphones might be helpful in times of stress, which may of the study.” Those in HRVB game condition were told to open inform future recommendations about the most effective way the Happify app, navigate to Breather, and “follow the to use a smartphone following a stressful experience. instructions on the app.” After the 5-minute phone manipulation period, the researcher returned to the room and instructed the Methods participant to continue answering a series of questionnaires. Twenty minutes after completion of the TSST, a third saliva Participants sample was collected. Forty minutes after the completion of the The study was approved by the University of California, Irvine TSST, a fourth saliva sample was collected. At the conclusion Institutional Review Board, and participants were recruited via of the study, the researcher and both judges debriefed the the University of California, Irvine undergraduate psychology participant. subject pool. These data were drawn from a larger project that Measures included additional research questions outside the scope of this study. For this particular study, a total of 140 participants were Demographics and Covariates examined (mean age 20.28, SD 2.68; 77.1% female; 45.7% Demographic information and potential covariates, including Asian; 27.9% Hispanic/Latino; 15.7% Caucasian; 6.4% African age, sex, ethnicity, socioeconomic status, perceived American). Participants were screened for eligibility and psychological stress, measures of daily phone use, time since excluded from participation if they were diagnosed with a waking, use of hormonal contraceptives, and caffeine intake, cardiovascular disease, were regularly taking mood altering or were collected via self-report. cardiovascular altering medication, regularly smoked cigarettes, http://games.jmir.org/2019/4/e15974/ JMIR Serious Games 2019 | vol. 7 | iss. 4 | e15974 | p. 4 (page number not for citation purposes) XSL FO RenderX JMIR SERIOUS GAMES Hunter et al were therefore controlled for in cortisol analyses. Baseline sAA Self-Reported Stress was associated with sAA recovery and was therefore controlled Participants were asked to indicate, “How stressed do you feel for in sAA analyses. Baseline self-reported stress was associated right now?” on a visual analog scale from 1-100. This simple with self-reported stress recovery and was therefore controlled one-item scale has been shown to be valid and reliable for for in self-reported stress analyses. assessing perceptions of acute stress [43]. Self-reported stress was assessed at three time points (baseline, post-TSST, +20 Independent sample t tests were used to conduct manipulation minutes recovery). checks and ensure that exposure to the TSST reliably increased self-reported stress, sAA, and cortisol from baseline (time 1) Physiological Stress to post-TSST stress (time 2). Repeated-measures mixed analysis Salivary cortisol and sAA were both collected to provide a broad of covariance was used to analyze the effect of condition on assessment of the physiological stress response. Since these each dependent variable. Since the phone manipulation occurred salivary biomarkers indicate activity of different physiological after the TSST, analyses focused on differences in recovery and stress systems and have different secretion times, the inclusion therefore used time (post-TSST stress at time 2 and +20 minute of both gives us a more comprehensive understanding of stress recovery at time 3) as the within-subject factor. Condition was effects. Salivary cortisol and sAA were collected using a passive included as a between-subject factor, and appropriate covariates drool technique with polypropylene cryovial salivettes at four were controlled for depending on the outcome of interest. time points. The first three samples were assayed for sAA, and Baseline values were controlled for to provide a more the last three samples were assayed for cortisol to accommodate conservative and unbiased estimate of between-subject for the differing secretion times of each analyte (ie, an differences in composite recovery values [44]. Post-hoc approximately 20-minute lag time for salivary cortisol secretion comparisons were conducted to examine specific pairwise into saliva compared to immediate secretion of sAA) and ensure differences when a significant effect of condition was found. that the collection timing aligned to capture measures of baseline, post-TSST, and +20 minute recovery time points. Results Experimental sessions were conducted in the afternoon (between 1 PM to 6 PM) to account for the diurnal rhythm of sAA and Manipulation Checks cortisol. Analysis of sAA from baseline (mean 85.31, SD 59.40) to Salivettes were stored at –80°C until batch analysis at the end post-TSST (mean 128.58, SD 88.53) revealed that participants of data collection at the laboratory of the Institute for displayed significant increases in sAA following the TSST Interdisciplinary Salivary Bioscience Research (University of (t =–4.78, P<.001). In addition, analysis of cortisol from California Irvine, Irvine, California). Before assaying, the baseline (mean 0.21, SD 0.11) to post-TSST (mean 0.34, SD samples were thawed for an hour to return them to room 0.24) showed that participants displayed significant increases temperature. For cortisol, all samples were assayed in duplicate in cortisol following the TSST, (t =-5.99, P<.001). Finally, by using an expanded-range high-sensitivity salivary cortisol analysis of self-reported stress from baseline (mean 22.73, SD enzyme immunoassay kit (Salimetrics, LLC, State College, 21.48) to post-TSST (mean 47.31, SD 29.37) demonstrated that Pennsylvania). The assay range of sensitivity was 0.007 to 3.0 participants displayed significant increases in self-reported stress µg/dL, and the average intraassay coefficient of variation was following the TSST (t =–7.96, P<.001). These results indicate 5.5%. For sAA, samples were tested in duplicate using a that TSST reliably increased psychological and physiological commercially available kinetic enzyme reaction assay kit stress. (Salimetrics, LLC). The assay range of sensitivity was 0.4-400 Differences in Salivary Alpha Amylase Recovery U/mL, and the average intraassay coefficient of variation was 3.3.%. Between Conditions Between-subject comparisons indicated that there was a Analytic Strategy significant main effect of condition on sAA recovery All dependent variables (self-reported stress, sAA, and cortisol) (F =3.78, P=.03; no phone: mean 10.078, SE 0.271; phone 2,133 were checked for skewness and kurtosis and transformed present: mean 10.007, SE 0.280; HRVB game: mean 9.132, SE accordingly. No transformation was performed for values of 0.266). Post-hoc comparisons revealed that those in the HRVB self-reported stress. Values of sAA were moderately skewed, game condition displayed significantly less sAA during recovery and a square root transformation was used to transform the than those in the no phone condition (t =2.48, P=.02) and the values to approximate a normal distribution. Values of cortisol phone present condition (t =2.26, P=.03). The no phone and were moderately skewed, and a logarithmic transformation was phone present conditions did not differ (t =–0.19, P=.85; used to transform the values to approximate a normal distribution. Outlying values above or below three SDs from Multimedia Appendix 2). Within-subject analyses revealed that the mean were removed. No outliers were removed for there was no significant main effect of time for sAA recovery self-reported stress, three outliers (2.1%) were removed for (F =.003, P=.96) and no significant interaction between time 1,133 sAA, and six outliers (2.8%) were removed for cortisol. and condition (F =0.081, P=.92). 2,133 Models controlled for covariates that were significantly associated with the dependent variable. Sex, time since waking, and baseline cortisol were associated with cortisol recovery and http://games.jmir.org/2019/4/e15974/ JMIR Serious Games 2019 | vol. 7 | iss. 4 | e15974 | p. 5 (page number not for citation purposes) XSL FO RenderX JMIR SERIOUS GAMES Hunter et al [52]. It should be noted that no mechanisms can be determined Differences in Cortisol Recovery Between Conditions for the lack of cortisol and self-reported stress, as we did not Although the cortisol levels declined during recovery for all find significant effects on these measures. Future studies should conditions, there was no main effect of condition on cortisol further investigate the mechanisms for why HRVB delivered recovery (F =1.19, P=.31). 2,126 via a smartphone influences stress recovery. Differences in Self-Reported Stress Recovery Between Interestingly, those who had their phones present during stress Conditions recovery did not glean any additional stress-buffering benefits Although self-reported stress declined during recovery for all beyond those with no phone. Previous work has demonstrated conditions, there was no main effect of condition on that having a phone present, but not using it, leads to steep self-reported stress recovery (F =1.42, P=.24). declines in sAA during physiological recovery from a stressor 2,133 [16]. We failed to replicate this outcome. In the study by Hunter et al [16], participants had their phones with them while Discussion undergoing the stressor. In this study, participants only had their Principal Findings phones immediately after the study. This difference in timing implies that it may be helpful to have a phone present while In this study, we examined the effect of using or having a experiencing a stressor, but it provides little to no benefit when smartphone on psychological and physiological stress reduction present during recovery. In addition, a phone may serve as a during recovery. We found that those who used an HRVB “digital security blanket” in mildly stressful situations like social training app exhibited the lowest levels of sAA during recovery. exclusion but may not exert similarly beneficial effects under Specifically, those in the HRVB game condition released less more potent stressors such as the TSST. sAA during recovery than those who had their phones present or had no phone at all. These results indicate that engaging in Limitations a brief 5-minute HRVB training session on a smartphone can There are several limitations that limit the generalizability of effectively reduce stress-related sympathetic activity, as assessed these results. First, our sample is not representative of the by levels of sAA. Although the magnitude of the effect for the population at large. The majority of our participants were change in sAA was only small to medium (η =0.05) [45], it healthy young Asian women, all of whom were iPhone users was similar to previous studies [16,46]. The sAA findings are and college educated. Since we drew our sample from a particularly important because high levels of sAA are associated university population, our participants were likely wealthier, with a range of deleterious health-related outcomes such as younger, more dependent on their phone, and more educated asthma, frequency of illness, and chronic fatigue [47-49]; than the average person. Thus, these conclusions cannot be therefore, lower levels of sAA are desirable from a health extrapolated to all populations. perspective. Our findings provide health-related information In addition, the effectiveness of Breather for influencing sAA about the use of mHealth interventions on a smartphone. Since recovery compared to the other conditions may have been delayed physiological recovery can be predictive of risk for statistically limited by differences in baseline values. Those in long-term health issues [50], we can infer that using a serious the HRVB game condition had significantly lower levels of sAA game such as Breather when recovering from a stressful at baseline. These differences may have been due to a experience may provide long-term health benefits. methodological inconsistency, as the individuals in the HRVB Our study design did not allow us to conclusively determine game condition had a slightly different experience during the the mechanisms responsible for the stress-buffering effect, but baseline period before undergoing the TSST; they spent there are several possibilities for why Breather effectively aided approximately 2 minutes receiving training on the HRVB app. in stress recovery. The most obvious explanation is that Per methodological recommendations, these baseline values undergoing HRVB training increases parasympathetic activity, were controlled for to provide a more conservative and unbiased which is typically inversely related to sympathetic indicators estimate of between-subject differences in recovery [43]. such as sAA. Thus, the low levels of sAA for those in the HRVB Without the inclusion of baseline sAA as a covariate in the game condition may be indicative of direct physiological models, there would have been greater statistical differences alterations induced by the use of Breather. In addition, between HRVB game use and the other conditions. Although psychological factors may have played a role in explaining sAA this statistical decision does limit the magnitude of our sAA recovery. The simple distraction induced by diverting cognitive recovery findings, these differences in baseline raise an attention away from ruminating thoughts about the stressor may interesting point about the ways in which Breather influences have positively contributed to the effects. Furthermore, reactions to a stressor. If, indeed, the brief training period parasympathetic activity has been associated with increases in reduced baseline sAA and sAA reactivity to the stressor, then positive valence and low arousal emotions such as calmn [24], using an HRVB serious game like Breather could possibly be which suggests that feelings of calm may have also played a an effective method for buffering stress reactivity as well as role in stress recovery. Finally, it is possible that the ability to recovery and may be an advisable activity to engage in prior to monitor stress responses via the visual interface of Breather a major stressor. Before any recommendations can be made, increased perceptions of control, which subsequently alleviated future studies should explore the optimal timing for HRVB feelings of stress. This is due to the fact that acute stress is often implementation and determine whether it is most effective induced by a perceived lack of control [51], and when that before or after a stressor. perceived control is increased, it can inhibit autonomic arousal http://games.jmir.org/2019/4/e15974/ JMIR Serious Games 2019 | vol. 7 | iss. 4 | e15974 | p. 6 (page number not for citation purposes) XSL FO RenderX JMIR SERIOUS GAMES Hunter et al Additionally, the effectiveness of Breather may have been importance of assessing both when contemplating health hindered by the way in which the participant interacted with relevance of stress or psychological outcomes [54]. Additionally, the app and understood the directions. During this training there is substantial variation based on individual factors, such period, information about the purpose of using this app (eg, this as demographics, in the association of subjective and objective activity makes you more relaxed and less stressed) was hidden measures of stress [55]. Furthermore, studies examining the from the participant in order to reduce demand characteristics convergence of self-report and physiological measures of stress and maintain internal validity across conditions. However, the have found that the assessments are highly correlated during success of biofeedback training hinges on the individuals’ the TSST, but not before or after [42]. Thus, it is not surprising perception that they are actively controlling their physiological that sAA was the only metric that yielded significant results. functions in an effort to reduce stress [8]. Without this The significant sAA finding provides valuable information understanding about the purpose of the activity, the biofeedback about how a HRVB training game via an mHealth app may aid exercise was likely less effective for the participants. In these in stress recovery; however, future studies should consider a ways, methodological constraints may have led to a more wider range of health-related outcomes. conservative effect of Breather compared to the other conditions. Finally, it should be acknowledged that the scope of this study Furthermore, user error issues that occurred within the app may did not allow us to conclusively determine whether using the have limited the effectiveness of Breather. The program requires HRVB app was more or less effective than performing other the user’s finger to be placed very precisely on the light sensor actions on one’s phone. Although past research is mixed on to monitor heart rate change. It is sometimes difficult to maintain how phone use influences stress recovery [17,18], there is great this position, and warnings pop up on the screen each time a potential for future researchers to explore how unstructured finger is placed incorrectly. Based on participant feedback, these phone use (eg, listening to music, browsing social media) could warnings made individuals feel as if they were performing impact physiological and psychological stress. Given the wide poorly, which may have induced further stress rather than variety of potential ways in which people can use their phones, alleviate it. To investigate whether user error played a role, future studies should further investigate the effects of various adherence to finger placement was assessed using metrics types of phone interactions on stress recovery. provided from the app’s database. Data showed that users had Conclusions and Implications their fingers placed correctly for approximately 96% of the time; Based on these results, one can conclude that completing HRVB however, that still means that for 4% of the session, they were training on an app such as Happify may be a practical and getting warnings telling them, “please place your finger on the effective strategy for reducing acute physiological stress. It is sensor.” This may have been bothersome and unduly reduced often not feasible to use a smartphone to buffer stress while the effectiveness of Breather, which is important to consider in undergoing a stressor, but it is practical and ecologically valid future efficacy tests and real-life applications. to use a phone immediately after one has experienced a stressful When considering a more comprehensive assessment of stress, experience. Our smartphones are conveniently with us at most conclusions from this study must be tempered by the lack of times, and thus, we have this effective stress-reducing tool at significant group differences for salivary cortisol and our disposal anytime and anywhere we need it. To further self-reported stress. Based on these discrepancies, we can only examine how smartphones can aid in stress recovery, future conclude that the HRVB game had a targeted effect on research should investigate the mechanisms underlying how a autonomic nervous system recovery as opposed to a general gamified stress-reducing app may buffer stress and how it effect on all types of biological and psychological stress compares to other ways of using a phone. This will inform future recovery. These inconsistencies in stress outcomes may be due interventions and provide recommendations for the development to a variety of reasons. First, cortisol and sAA represent activity of other stress-buffering tools that can be delivered through in different arms of the stress system and are not correlated at smartphone apps. a 1:1 level [36,53]. Numerous studies have discovered Results such as these are beginning to change the narrative about significant sAA results, but not cortisol, during stress recovery the effect of smartphones on our well-being. Although it is [37,38]. The one study that examined both biomarkers in the important to recognize the deleterious effects of these devices context of phone usage only found significant sAA effects [16]. on our lives, it may be even more critical to recognize the Our findings indicate that the HRVB training had a more robust positive potential of smartphones and begin to develop and use impact on autonomic nervous system activity (indicated by sAA technology in ways that augment well-being. Instead of simply measures), which makes sense because HRVB training hoping that individuals use technology in a beneficial manner, specifically targets fluctuations in cardiovascular activity that it is imperative that the hardware and software are designed in is intricately tied to autonomic activity [36]. In addition, the a way that facilitates positive behavior, thoughts, and intervention period was short (about 5 minutes), which may not interactions. Designing tools that take advantage of the have been enough time to impact cortisol, often viewed as a technological affordances and ubiquity of smartphones to put chronic stress marker with a delayed release [53]. The stress-reducing tools in the palm of one’s hand is a promising discrepancy between self-reported and physiological stress is strategy for finding ways for smartphones to maximize quite common in studies that assess both constructs [17,34,42] well-being. and one of the reasons many researchers argue for the http://games.jmir.org/2019/4/e15974/ JMIR Serious Games 2019 | vol. 7 | iss. 4 | e15974 | p. 7 (page number not for citation purposes) XSL FO RenderX JMIR SERIOUS GAMES Hunter et al Acknowledgments This project was funded by Happify Health. Conflicts of Interest ACP and ALW are full-time employees of Happify Health. However, all study design decisions, data collection, and analyses were performed by JFH, MSO, and SDP at the University of California, Irvine. Multimedia Appendix 1 A brief demo video of Breather on the Happify app. [MP4 File (MP4 Video), 157169 KB-Multimedia Appendix 1] Multimedia Appendix 2 Levels of salivary alpha amylase during recovery by experimental conditions. [PNG File , 27 KB-Multimedia Appendix 2] References 1. Ralph BCW, Thomson DR, Cheyne JA, Smilek D. Media multitasking and failures of attention in everyday life. Psychol Res 2014 Sep;78(5):661-669. [doi: 10.1007/s00426-013-0523-7] [Medline: 24178629] 2. Roberts JA, Yaya LHP, Manolis C. The invisible addiction: cell-phone activities and addiction among male and female college students. J Behav Addict 2014 Dec;3(4):254-265 [FREE Full text] [doi: 10.1556/JBA.3.2014.015] [Medline: 25595966] 3. Rosen LD, Lim AF, Felt J, Carrier LM, Cheever NA, Lara-Ruiz JM, et al. Media and technology use predicts ill-being among children, preteens and teenagers independent of the negative health impacts of exercise and eating habits. Comput Human Behav 2014 Jun;35:364-375 [FREE Full text] [doi: 10.1016/j.chb.2014.01.036] [Medline: 25717216] 4. Twenge JM, Joiner TE, Rogers ML, Martin GN. Increases in Depressive Symptoms, Suicide-Related Outcomes, and Suicide Rates Among U.S. Adolescents After 2010 and Links to Increased New Media Screen Time. Clinical Psychological Science 2017 Nov 14;6(1):3-17. [doi: 10.1177/2167702617723376] 5. McEwen BS, Gianaros PJ. Stress- and allostasis-induced brain plasticity. Annu Rev Med 2011;62:431-445 [FREE Full text] [doi: 10.1146/annurev-med-052209-100430] [Medline: 20707675] 6. McEwen BS. Stress, adaptation, and disease. Allostasis and allostatic load. Ann N Y Acad Sci 1998 May 01;840:33-44. [doi: 10.1111/j.1749-6632.1998.tb09546.x] [Medline: 9629234] 7. Goldenberg DL, Kaplan KH, Nadeau MG, Brodeur C, Smith S, Schmid CH. A Controlled Study of a Stress-Reduction, Cognitive-Behavioral Treatment Program in Fibromyalgia. Journal of Musculoskeletal Pain 2010 Jan 16;2(2):53-66. [doi: 10.1300/j094v02n02_05] 8. Moss D. Heart rate variability and biofeedback. Psychophysiology Today: The Magazine for Mind-Body Medicine 2004;1:4-11. 9. Free C, Phillips G, Felix L, Galli L, Patel V, Edwards P. The effectiveness of M-health technologies for improving health and health services: a systematic review protocol. BMC Res Notes 2010;3:250 [FREE Full text] [doi: 10.1186/1756-0500-3-250] [Medline: 20925916] 10. Ward AF, Duke K, Gneezy A, Bos MW. Brain Drain: The Mere Presence of One’s Own Smartphone Reduces Available Cognitive Capacity. Journal of the Association for Consumer Research 2017 Apr;2(2):140-154. [doi: 10.1086/691462] 11. Misra S, Cheng L, Genevie J, Yuan M. The iPhone Effect. Environment and Behavior 2014 Jul;48(2):275-298. [doi: 10.1177/0013916514539755] 12. Horrey WJ, Wickens CD. Examining the impact of cell phone conversations on driving using meta-analytic techniques. Hum Factors 2006;48(1):196-205. [doi: 10.1518/001872006776412135] [Medline: 16696268] 13. Gerin W, Davidson KW, Christenfeld NJS, Goyal T, Schwartz JE. The role of angry rumination and distraction in blood pressure recovery from emotional arousal. Psychosom Med 2006;68(1):64-72. [doi: 10.1097/01.psy.0000195747.12404.aa] [Medline: 16449413] 14. Master SL, Eisenberger NI, Taylor SE, Naliboff BD, Shirinyan D, Lieberman MD. A picture's worth: partner photographs reduce experimentally induced pain. Psychol Sci 2009 Nov;20(11):1316-1318. [doi: 10.1111/j.1467-9280.2009.02444.x] [Medline: 19788531] 15. Brown SL, Nesse RM, Vinokur AD, Smith DM. Providing social support may be more beneficial than receiving it: results from a prospective study of mortality. Psychol Sci 2003 Jul;14(4):320-327. [Medline: 12807404] 16. Hunter JF, Hooker ED, Rohleder N, Pressman SD. The Use of Smartphones as a Digital Security Blanket: The Influence of Phone Use and Availability on Psychological and Physiological Responses to Social Exclusion. Psychosom Med 2018 May;80(4):345-352. [doi: 10.1097/PSY.0000000000000568] [Medline: 29521885] http://games.jmir.org/2019/4/e15974/ JMIR Serious Games 2019 | vol. 7 | iss. 4 | e15974 | p. 8 (page number not for citation purposes) XSL FO RenderX JMIR SERIOUS GAMES Hunter et al 17. Rus HM, Tiemensma J. Social media as a shield: Facebook buffers acute stress. Physiol Behav 2018 Mar 01;185:46-54. [doi: 10.1016/j.physbeh.2017.12.021] [Medline: 29273455] 18. Rus HM, Tiemensma J. Social Media under the Skin: Facebook Use after Acute Stress Impairs Cortisol Recovery. Front Psychol 2017 Sep 19;8. [doi: 10.3389/fpsyg.2017.01609] 19. Hooker ED, Campos B, Pressman SD. It just takes a text: Partner text messages can reduce cardiovascular responses to stress in females. Computers in Human Behavior 2018 Jul;84:485-492. [doi: 10.1016/j.chb.2018.02.033] 20. Lin I, Peper E. Psychophysiological patterns during cell phone text messaging: a preliminary study. Appl Psychophysiol Biofeedback 2009 Mar;34(1):53-57. [doi: 10.1007/s10484-009-9078-1] [Medline: 19199025] 21. Afifi TD, Zamanzadeh N, Harrison K, Acevedo Callejas M. WIRED: The impact of media and technology use on stress (cortisol) and inflammation (interleukin IL-6) in fast paced families. Computers in Human Behavior 2018 Apr;81:265-273. [doi: 10.1016/j.chb.2017.12.010] 22. Fiordelli M, Diviani N, Schulz PJ. Mapping mHealth research: a decade of evolution. J Med Internet Res 2013;15(5):e95 [FREE Full text] [doi: 10.2196/jmir.2430] [Medline: 23697600] 23. Parks AC, Williams AL, Tugade MM, Hokes KE, Honomichl RD, Zilca RD. Testing a scalable web and smartphone based intervention to improve depression, anxiety, and resilience: A randomized controlled trial. Intnl J Wellbeing 2018 Dec 08;8(2):22-67. [doi: 10.5502/ijw.v8i2.745] 24. Lehrer PM, Gevirtz R. Heart rate variability biofeedback: how and why does it work? Front Psychol 2014;5:756 [FREE Full text] [doi: 10.3389/fpsyg.2014.00756] [Medline: 25101026] 25. Lacey BC, Lacey JI. Two-way communication between the heart and the brain. Significance of time within the cardiac cycle. Am Psychol 1978 Feb;33(2):99-113. [Medline: 637402] 26. Karemaker J, Lie KI. Heart rate variability: a telltale of health or disease. Eur Heart J 2000 Mar 15;21(6):435-437. [doi: 10.1053/euhj.1999.1969] [Medline: 10681483] 27. Del Pozo JM, Gevirtz RN, Scher B, Guarneri E. Biofeedback treatment increases heart rate variability in patients with known coronary artery disease. Am Heart J 2004 Mar;147(3):E11. [doi: 10.1016/j.ahj.2003.08.013] [Medline: 14999213] 28. Kleiger RE, Miller J, Bigger J, Moss AJ. Decreased heart rate variability and its association with increased mortality after acute myocardial infarction. The American Journal of Cardiology 1987 Feb;59(4):256-262. [doi: 10.1016/0002-9149(87)90795-8] 29. Dillon A, Kelly M, Robertson IH, Robertson DA. Smartphone Applications Utilizing Biofeedback Can Aid Stress Reduction. Front Psychol 2016;7:832 [FREE Full text] [doi: 10.3389/fpsyg.2016.00832] [Medline: 27378963] 30. Prinsloo GE, Rauch HGL, Lambert MI, Muench F, Noakes TD, Derman WE. The effect of short duration heart rate variability (HRV) biofeedback on cognitive performance during laboratory induced cognitive stress. Appl Cognit Psychol 2010 Oct 17;25(5):792-801. [doi: 10.1002/acp.1750] 31. Stein P. Washington University in St. Louis, School of Medicine. 2018. Validation of the Happify breather biofeedback exercise to track heart rate variability using an optical sensor. URL: https://happify.com/health/results/HLS-05.pdf [accessed 2019-11-11] 32. Vaschillo E, Lehrer P, Rishe N, Konstantinov M. Heart rate variability biofeedback as a method for assessing baroreflex function: A preliminary study of resonance in the cardiovascular system. Applied Psychophysiology and Biofeedback 2002;27(1). [doi: 10.1023/A:1014587304314] 33. Robins R, Fraley R, Krueger R. The self-report method. In: Handbook Of Research Methods In Personality Psychology. New York: The Guilford Press; 2019. 34. Campbell J, Ehlert U. Acute psychosocial stress: does the emotional stress response correspond with physiological responses? Psychoneuroendocrinology 2012 Aug;37(8):1111-1134. [doi: 10.1016/j.psyneuen.2011.12.010] [Medline: 22260938] 35. Hellhammer DH, Wüst S, Kudielka BM. Salivary cortisol as a biomarker in stress research. Psychoneuroendocrinology 2009 Feb;34(2):163-171. [doi: 10.1016/j.psyneuen.2008.10.026] 36. Nater UM, Rohleder N. Salivary alpha-amylase as a non-invasive biomarker for the sympathetic nervous system: current state of research. Psychoneuroendocrinology 2009 May;34(4):486-496. [doi: 10.1016/j.psyneuen.2009.01.014] [Medline: 19249160] 37. Payne LA, Hibel LC, Granger DA, Tsao JCI, Zeltzer LK. Relationship of Salivary Alpha Amylase and Cortisol to Social Anxiety in Healthy Children Undergoing Laboratory Pain Tasks. J Child Adolesc Behav 2014;2 [FREE Full text] [doi: 10.4172/jcalb.1000129] [Medline: 25525630] 38. van Veen JF, van Vliet IM, Derijk RH, van Pelt J, Mertens B, Zitman FG. Elevated alpha-amylase but not cortisol in generalized social anxiety disorder. Psychoneuroendocrinology 2008 Nov;33(10):1313-1321. [doi: 10.1016/j.psyneuen.2008.07.004] [Medline: 18757137] 39. Winslow BD, Chadderdon GL, Dechmerowski SJ, Jones DL, Kalkstein S, Greene JL, et al. Development and Clinical Evaluation of an mHealth Application for Stress Management. Front Psychiatry 2016 Jul;7:130 [FREE Full text] [doi: 10.3389/fpsyt.2016.00130] [Medline: 27507949] 40. Kirschbaum C, Pirke KM, Hellhammer DH. The 'Trier Social Stress Test'--a tool for investigating psychobiological stress responses in a laboratory setting. Neuropsychobiology 1993;28(1-2):76-81. [doi: 10.1159/000119004] [Medline: 8255414] http://games.jmir.org/2019/4/e15974/ JMIR Serious Games 2019 | vol. 7 | iss. 4 | e15974 | p. 9 (page number not for citation purposes) XSL FO RenderX JMIR SERIOUS GAMES Hunter et al 41. Allen AP, Kennedy PJ, Dockray S, Cryan JF, Dinan TG, Clarke G. The Trier Social Stress Test: Principles and practice. Neurobiol Stress 2017 Feb;6:113-126 [FREE Full text] [doi: 10.1016/j.ynstr.2016.11.001] [Medline: 28229114] 42. Hellhammer J, Schubert M. The physiological response to Trier Social Stress Test relates to subjective measures of stress during but not before or after the test. Psychoneuroendocrinology 2012 Jan;37(1):119-124. [doi: 10.1016/j.psyneuen.2011.05.012] [Medline: 21689890] 43. Lesage F, Berjot S, Deschamps F. Clinical stress assessment using a visual analogue scale. Occup Med (Lond) 2012 Dec;62(8):600-605 [FREE Full text] [doi: 10.1093/occmed/kqs140] [Medline: 22965867] 44. Overall JE, Doyle SR. Implications of chance baseline differences in repeated measurement designs. J Biopharm Stat 1994 Jul;4(2):199-216. [doi: 10.1080/10543409408835083] [Medline: 7951275] 45. Richardson JT. Eta squared and partial eta squared as measures of effect size in educational research. Educational Research Review 2011 Jan;6(2):135-147. [doi: 10.1016/j.edurev.2010.12.001] 46. Stroud LR, Foster E, Papandonatos GD, Handwerger K, Granger DA, Kivlighan KT, et al. Stress response and the adolescent transition: performance versus peer rejection stressors. Dev Psychopathol 2009;21(1):47-68 [FREE Full text] [doi: 10.1017/S0954579409000042] [Medline: 19144222] 47. Granger DA, Kivlighan KT, Blair C, El-Sheikh M, Mize J, Lisonbee JA, et al. Integrating the measurement of salivary α-amylase into studies of child health, development, and social relationships. Journal of Social and Personal Relationships 2016 Jun 29;23(2):267-290. [doi: 10.1177/0265407506062479] 48. Granger DA, Kivlighan KT, el-Sheikh M, Gordis EB, Stroud LR. Salivary alpha-amylase in biobehavioral research: recent developments and applications. Ann N Y Acad Sci 2007 Mar;1098:122-144. [doi: 10.1196/annals.1384.008] [Medline: 17332070] 49. Wolf JM, Nicholls E, Chen E. Chronic stress, salivary cortisol, and alpha-amylase in children with asthma and healthy children. Biol Psychol 2008 Apr;78(1):20-28. [doi: 10.1016/j.biopsycho.2007.12.004] [Medline: 18243483] 50. Stewart JC, France CR. Cardiovascular recovery from stress predicts longitudinal changes in blood pressure. Biol Psychol 2001 Nov;58(2):105-120. [doi: 10.1016/s0301-0511(01)00105-3] [Medline: 11600240] 51. Eysenck M. Anxiety: The cognitive perspective. London, UK: Psychology Press; 2013. 52. Leotti LA, Iyengar SS, Ochsner KN. Born to choose: the origins and value of the need for control. Trends Cogn Sci 2010 Oct;14(10):457-463 [FREE Full text] [doi: 10.1016/j.tics.2010.08.001] [Medline: 20817592] 53. Engert V, Vogel S, Efanov SI, Duchesne A, Corbo V, Ali N, et al. Investigation into the cross-correlation of salivary cortisol and alpha-amylase responses to psychological stress. Psychoneuroendocrinology 2011 Oct;36(9):1294-1302. [doi: 10.1016/j.psyneuen.2011.02.018] [Medline: 21470780] 54. Diener E, Pressman SD, Hunter J, Delgadillo-Chase D. If, Why, and When Subjective Well-Being Influences Health, and Future Needed Research. Appl Psychol Health Well-Being 2017 Jul 14;9(2):133-167. [doi: 10.1111/aphw.12090] 55. Föhr T, Tolvanen A, Myllymäki T, Järvelä-Reijonen E, Rantala S, Korpela R, et al. Subjective stress, objective heart rate variability-based stress, and recovery on workdays among overweight and psychologically distressed individuals: a cross-sectional study. J Occup Med Toxicol 2015;10:39 [FREE Full text] [doi: 10.1186/s12995-015-0081-6] [Medline: 26504485] Abbreviations HRV: heart rate variability HRVB: heart rate variability biofeedback mHealth: mobile health mHealth: mobile health sAA: salivary alpha amylase TSST: Trier Social Stress Task Edited by G Eysenbach; submitted 23.08.19; peer-reviewed by K Stasiak, D Banks, R Ciptaningtyas; comments to author 17.09.19; revised version received 10.10.19; accepted 31.10.19; published 26.11.19 Please cite as: Hunter JF, Olah MS, Williams AL, Parks AC, Pressman SD JMIR Serious Games 2019;7(4):e15974 URL: http://games.jmir.org/2019/4/e15974/ doi: 10.2196/15974 PMID: 31769761 http://games.jmir.org/2019/4/e15974/ JMIR Serious Games 2019 | vol. 7 | iss. 4 | e15974 | p. 10 (page number not for citation purposes) XSL FO RenderX JMIR SERIOUS GAMES Hunter et al ©John F Hunter, Meryl S Olah, Allison L Williams, Acacia C Parks, Sarah D Pressman. Originally published in JMIR Serious Games (http://games.jmir.org), 26.11.2019. This is an open-access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in JMIR Serious Games, is properly cited. The complete bibliographic information, a link to the original publication on http://games.jmir.org, as well as this copyright and license information must be included. http://games.jmir.org/2019/4/e15974/ JMIR Serious Games 2019 | vol. 7 | iss. 4 | e15974 | p. 11 (page number not for citation purposes) XSL FO RenderX http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png JMIR Serious Games JMIR Publications

Effect of Brief Biofeedback via a Smartphone App on Stress Recovery: Randomized Experimental Study

Download PDF
11 pages

Loading next page...
 
/lp/jmir-publications/effect-of-brief-biofeedback-via-a-smartphone-app-on-stress-recovery-by59uE6K0V
Publisher
JMIR Publications
Copyright
Copyright © The Author(s). Licensed under Creative Commons Attribution cc-by 4.0
ISSN
2291-9279
DOI
10.2196/15974
Publisher site
See Article on Publisher Site

Abstract

Background: Smartphones are often vilified for negatively influencing well-being and contributing to stress. However, these devices may, in fact, be useful in times of stress and, in particular, aid in stress recovery. Mobile apps that deliver evidence-based techniques for stress reduction, such as heart rate variability biofeedback (HRVB) training, hold promise as convenient, accessible, and effective stress-reducing tools. Numerous mobile health apps that may potentially aid in stress recovery are available, but very few have demonstrated that they can influence health-related physiological stress parameters (eg, salivary biomarkers of stress). The ability to recover swiftly from stress and reduce physiological arousal is particularly important for long-term health, and thus, it is imperative that evidence is provided to demonstrate the effectiveness of stress-reducing mobile health apps in this context. Objective: The purpose of this research was to investigate the physiological and psychological effects of using a smartphone app for HRVB training following a stressful experience. The efficacy of the gamified Breather component of the Happify mobile health app was examined in an experimental setting. Methods: In this study, participants (N=140) underwent a laboratory stressor and were randomly assigned to recover in one of three ways: with no phone present, with a phone present, with the HRBV game. Those in the no phone condition had no access to their phone. Those in the phone present condition had their phone but did not use it. Those in the HRVB game condition used the serious game Breather on the Happify app. Stress recovery was assessed via repeated measures of salivary alpha amylase, cortisol, and self-reported acute stress (on a 1-100 scale). Results: Participants in the HRVB game condition had significantly lower levels of salivary alpha amylase during recovery than participants in the other conditions (F =3.78, P=.03). There were no significant differences among the conditions during 2,133 recovery for salivary cortisol levels or self-reported stress. Conclusions: These results show that engaging in a brief HRVB training session on a smartphone reduces levels of salivary alpha amylase following a stressful experience, providing preliminary evidence for the effectiveness of Breather in improving physiological stress recovery. Given the known ties between stress recovery and future well-being, this study provides a possible mechanism by which gamified biofeedback apps may lead to better health. (JMIR Serious Games 2019;7(4):e15974) doi: 10.2196/15974 KEYWORDS heart rate variability biofeedback; stress recovery; salivary alpha amylase; smartphone; mHealth http://games.jmir.org/2019/4/e15974/ JMIR Serious Games 2019 | vol. 7 | iss. 4 | e15974 | p. 1 (page number not for citation purposes) XSL FO RenderX JMIR SERIOUS GAMES Hunter et al beneficial for stress recovery. In fact, when looked at more Introduction broadly, greater use of smartphones is associated with higher levels of physiological stress [21]. Therefore, if we hope to Background highlight the most effective ways to use a phone to reduce stress, Although smartphones are often criticized for contributing to it may be important to go beyond natural phone use habits and, ill-being [1-4], these devices hold great potential for improving instead, provide structured apps that are specifically designed one’s well-being if utilized properly in specific contexts. for stress reduction. Smartphones may be particularly useful as tools that provide One promising way to use a smartphone to aid in stress reduction gamified apps to deliver stress-buffering interventions. Stress is by engaging with a mobile health (mHealth) app. mHealth is prevalent in many peoples’ lives, and its accumulated effects apps can utilize technological capabilities (eg, phone sensors, can lead to various undesirable physical and mental health interactive displays) and draw on the ubiquity of smartphones outcomes, such as an increased risk for mortality [5]. Many of in everyday life to deliver functional and convenient these negative outcomes are due to prolonged activation of one’s interventions [22]. By combining evidence-based stress systems [6]. However, if individuals employ strategies stress-reduction techniques with an engaging and ever-present that promote more efficient recovery from stressors, some of medium, mHealth apps hold great promise for mitigating the the negative long-term impacts may be mitigated. negative effects of stress. Why do smartphones present a promising opportunity for Happify is an mHealth app that provides gamified activities altering stress recovery? Psychologists have developed a variety aimed at improving well-being and reducing stress [23]. Happify of evidence-backed strategies that aid in stress reduction [7], is representative of multiple aspects of other mHealth apps such as biofeedback training, which directs individuals to because it employs various smartphone technological monitor and attempt to alter their physiological arousal pattern capabilities (eg, sensors, visual and audio components, engaging [8]. Smartphones are ideally situated to be used as a tool for interface) and incorporates empirically validated strategies to biofeedback training and to combat the negative effects of stress deliver training in a self-contained package. Within the Happify because they are popular, conveniently accessible, and have an suite of activities, the Breather function delivers heart rate array of technological capabilities [9]. Since these devices are variability biofeedback (HRVB) training (Multimedia Appendix nearly omnipresent in daily life, they can deliver interventions 1). HRVB is a particularly effective stress-reducing activity that and assistance wherever and whenever needed. targets changes in heart rate variability (HRV) by regulating Smartphones provide a range of possibilities for helping breathing and bringing awareness to physiological function individuals recover from a stressful experience and may even [24]. HRV is an index of beat-to-beat changes in heart rate and do so when not actively used. Even when merely present, is an indicator of parasympathetic nervous system activity [25]. smartphones serve as symbols that can cause cognitive When undergoing a stressor, the typical response is for our distraction [10] or activate representations of social connections sympathetic nervous system to activate and parasympathetic [11]. Distraction induced by smartphones has generally been activity to decline (indicating low HRV). However, an adaptive viewed as detrimental [12]; however, such distraction can be response to a stressor would be for an individual to exhibit beneficial when faced with a stressor, because it can draw higher HRV. This is because greater fluctuations in heart rhythm attention away from the negative stimuli at hand and help (higher HRV) indicate greater adaptability to physiological circumvent rumination [13]. In addition, symbolic needs than fewer fluctuations (lower HRV) [24]. When HRV representations of social connections can elicit perceptions of is higher, it is a sign that our cardiovascular system (and multiple social support [14], which, when perceived passively, is the associated systems) is responding appropriately to environmental most effective form of support for stress alleviation [15]. By demands (eg, a stressor). Thus, using HRVB to increase HRV providing distraction and perceived social support, the mere may be helpful when recovering from a stressor because it presence of a smartphone may aid in stress recovery by serving activates our parasympathetic nervous system and allows us to as a “digital security blanket” in instances of social stress [16]. more quickly reduce physiological arousal. It is also important Thus, it is important to investigate more fully how merely having to note that high HRV is considered a protective factor against a smartphone in one’s presence may aid in stress alleviation. cardiovascular disease and is generally associated with good health and well-being [26]. Additionally, low HRV has Research has demonstrated that actually using one’s smartphone numerous negative implications for long-term health outcomes, can be beneficial or detrimental for stress recovery, depending such as increased risk for mortality and morbidity [27,28]. on how and when the device is used. For example, research has HRVB training has been successfully utilized in a variety of shown that using social media sites such as Facebook can acute stress settings and is well-validated technique for reducing provide social resources that sometimes help buffer acute stress stress [29,30]. The goal of undergoing a 5-minute guided session [17], but at other times, fail to do so [18]. In some instances, on Breather is for the user to increase HRV and recover social support gleaned via text message can reduce effectively from a stressful experience. cardiovascular responses to stress [19]. However, sending and receiving text messages can also increase physiological Delivering HRVB through a smartphone app provides many indicators of stress such as heart rate, respiration, and skin advantages over traditional training. Breather overcomes barriers conductance [20]. These mixed findings concerning how phone of nondigital HRVB interventions (eg, bulky and expensive use influences stress underscore the fact that the ways in which equipment, lengthy sessions) because it is quick to administer, we commonly interact with our devices are not universally is portable and readily accessible, and has all the hardware and http://games.jmir.org/2019/4/e15974/ JMIR Serious Games 2019 | vol. 7 | iss. 4 | e15974 | p. 2 (page number not for citation purposes) XSL FO RenderX JMIR SERIOUS GAMES Hunter et al software integrated into a single device. Breather has taken (Figure 1B). The meter directs the individual to breathe in for advantage of mobile technology affordances to package an 4 seconds and then breathe out for 6 seconds. This 10-second HRVB product in ways that should allow it to be used across a breathing cycle is ideal for creating a resonant frequency (ie, variety of stressful contexts. breathing and heart rate align) that should maximize HRV [32]. Users of Breather generate HRV observations by placing their After calibration is complete, the interface changes into a index finger over the camera of their smartphone (Figure 1A). calming nature scene (eg, underwater coral bed, tropical beach, The light from the camera can be used to monitor blood volume mountaintops). The user then travels through the natural changes within the finger. This process (ie, environment while he/she continues to breathe along with the photoplethysmography) relies on measuring changes in light meter (Figure 2A). As they breathe deeply and regularly, their absorption on the skin of the finger. Algorithms programmed HRV increases and the scene becomes more complex and by Happify software engineers then transform those data into beautiful (eg, coral polyps bloom, flowers grow; Figure 2B). a simple signal that is visible to the user. The accuracy of this By visually monitoring the changes in the scene, individuals technology for determining HRV has been recently validated are undergoing HRVB; this process is analogous to how in a series of experiments that compared simultaneously individuals monitor electrocardiogram signals in more traditional obtained HRV metrics from Happify Breather and traditional “nongamified” HRVB trainings. The app is designed to increase electrocardiogram techniques using electrodes [31]. HRV and reduce stress if the users adhere to the directions properly for a 5-minute session. After calibrating the heart rate of the individual, a circular meter directs the individual to follow the breathing patterns on screen Figure 1. On-screen instructions for obtaining heart rate variability measurement and calibrating breathing guidance. Figure 2. Example of how the full display unfolds when an individual is using Breather. multimodal approach that combines subjective and objective Assessment of Stress assessments [34]. In this paper, we used a multimethodological approach to One of the most effective, reliable, and efficient ways to capture determine the effects of smartphones on stress recovery. Stress physiological measurements of stress is to analyze salivary can be assessed in a variety of ways, and each method provides biomarkers. Salivary cortisol is a downstream output of unique insight into the complex dynamics of how stress impacts hypothalamic-pituitary-adrenal axis system activation and is our bodies and brains. One of the most common ways to assess one of the most widely used and reliable measures of stress is to ask individuals to subjectively rate their stress level. physiological stress [35]. Higher levels of salivary cortisol Although self-report is advantageous for assessing perceived indicate greater physiological stress. Another emerging indicator stress, there are problems of bias (eg, self-presentation concerns) of physiological stress is salivary alpha amylase (sAA), which that limit the accuracy and generalizability of these assessments is an indicator of autonomic nervous system activity and is most [33]. Due to its complexity, the most appropriate and strongly tied with sympathetic nervous system activity, the comprehensive manner in which stress is assessed is a system responsible for the “fight-or-flight” response [36]. When http://games.jmir.org/2019/4/e15974/ JMIR Serious Games 2019 | vol. 7 | iss. 4 | e15974 | p. 3 (page number not for citation purposes) XSL FO RenderX JMIR SERIOUS GAMES Hunter et al physiologically aroused, sAA is released via the salivary glands were not fluent in English, or did not have an iPhone. All and indicates an immediate stress response. In some cases, sAA participants were University of California, Irvine, students and is more strongly tied to stress and anxiety than cortisol [37,38], consented to participate. Data collection took place from July and sAA (but not cortisol) has also been shown to be influenced 2018 through February 2019. by smartphones while recovering from a stressor [16]. Thus, Procedures sAA is considered our primary outcome of interest. These Participants underwent an approximately 90-minute laboratory salivary assessments of hypothalamic-pituitary-adrenal and session. All participant phones were confiscated at the beginning autonomic nervous system activities combined with self-report of the study under the pretext of measuring the external physical give researchers a comprehensive understanding of physiological properties of the phone, which allowed the experimenter to later responses to stress. manipulate the phone conditions without arousing suspicion This Study and ensure that all participants experienced similar This study investigated the effectiveness of using an HRVB circumstances of having their phone taken away. For participants smartphone app to aid in stress recovery. In order to account randomly assigned to the HRVB game condition, the Happify for the potential stress-buffering effects of simply having a app was installed on their phone and the experimenter guided phone [16], we included a condition in which individuals had them through the calibration settings of the Breather function a phone in their presence. Thus, use of the HRVB app was while carefully concealing any indication that the purpose of compared to two control conditions, one in which no phone was using Breather was to reduce stress. Participants in the other present and one in which individuals had their smartphones conditions filled out surveys during this time. After participants present when recovering from a stressor. completed a series of questionnaires and acclimated to the laboratory environment (approximately 25 minutes), the To examine how these different types of smartphone interactions experimenter returned to the laboratory room and collected a influence stress recovery, a laboratory experiment was baseline saliva sample. Participants were instructed in the conducted in which participants underwent a standardized passive drool technique of collecting their own saliva sample. stressor, used their phone in a particular way depending on their assigned condition, and were assessed on a range of Participants then underwent a shortened version of the Trier psychological and physiological stress indicators. We Social Stress Task (TSST) [40,41] to induce psychological and hypothesized that those in the HRVB game condition would physiological stress. The TSST consists of participants recover from the stressor more effectively than those who had undergoing a public speaking task and arithmetic task in front their phones present or had no phone at all. of a panel of critically evaluative judges. The TSST has been shown to be a valid and reliable instrument for inducing This study is one of the first empirical investigations to assess physiological and psychological stress responses [42]. the effects of smartphone app usage on salivary biomarkers of Immediately after the conclusion of the TSST, participants physiological stress [39]. To our knowledge, it is also the first collected another saliva sample and self-reported their feelings to examine the stress-buffering effects of an HRVB intervention of stress. For the next 5 minutes, participants were left alone in delivered via a smartphone without any external equipment. In the room and interacted with their phone in a particular way addition, since simply having a phone in your presence has been depending on condition. Those in the no phone condition did shown to aid in stress recovery, the inclusion of separate not have their phone returned and were told to sit quietly for experimental conditions for a HRVB game and mere phone the next 5 minutes while the next portion of the study was presence enabled us to differentiate their effects on stress. The prepared. Those in the phone present condition were given their results of this study will help our understanding of why phone but told “please do not use your phone for the remainder smartphones might be helpful in times of stress, which may of the study.” Those in HRVB game condition were told to open inform future recommendations about the most effective way the Happify app, navigate to Breather, and “follow the to use a smartphone following a stressful experience. instructions on the app.” After the 5-minute phone manipulation period, the researcher returned to the room and instructed the Methods participant to continue answering a series of questionnaires. Twenty minutes after completion of the TSST, a third saliva Participants sample was collected. Forty minutes after the completion of the The study was approved by the University of California, Irvine TSST, a fourth saliva sample was collected. At the conclusion Institutional Review Board, and participants were recruited via of the study, the researcher and both judges debriefed the the University of California, Irvine undergraduate psychology participant. subject pool. These data were drawn from a larger project that Measures included additional research questions outside the scope of this study. For this particular study, a total of 140 participants were Demographics and Covariates examined (mean age 20.28, SD 2.68; 77.1% female; 45.7% Demographic information and potential covariates, including Asian; 27.9% Hispanic/Latino; 15.7% Caucasian; 6.4% African age, sex, ethnicity, socioeconomic status, perceived American). Participants were screened for eligibility and psychological stress, measures of daily phone use, time since excluded from participation if they were diagnosed with a waking, use of hormonal contraceptives, and caffeine intake, cardiovascular disease, were regularly taking mood altering or were collected via self-report. cardiovascular altering medication, regularly smoked cigarettes, http://games.jmir.org/2019/4/e15974/ JMIR Serious Games 2019 | vol. 7 | iss. 4 | e15974 | p. 4 (page number not for citation purposes) XSL FO RenderX JMIR SERIOUS GAMES Hunter et al were therefore controlled for in cortisol analyses. Baseline sAA Self-Reported Stress was associated with sAA recovery and was therefore controlled Participants were asked to indicate, “How stressed do you feel for in sAA analyses. Baseline self-reported stress was associated right now?” on a visual analog scale from 1-100. This simple with self-reported stress recovery and was therefore controlled one-item scale has been shown to be valid and reliable for for in self-reported stress analyses. assessing perceptions of acute stress [43]. Self-reported stress was assessed at three time points (baseline, post-TSST, +20 Independent sample t tests were used to conduct manipulation minutes recovery). checks and ensure that exposure to the TSST reliably increased self-reported stress, sAA, and cortisol from baseline (time 1) Physiological Stress to post-TSST stress (time 2). Repeated-measures mixed analysis Salivary cortisol and sAA were both collected to provide a broad of covariance was used to analyze the effect of condition on assessment of the physiological stress response. Since these each dependent variable. Since the phone manipulation occurred salivary biomarkers indicate activity of different physiological after the TSST, analyses focused on differences in recovery and stress systems and have different secretion times, the inclusion therefore used time (post-TSST stress at time 2 and +20 minute of both gives us a more comprehensive understanding of stress recovery at time 3) as the within-subject factor. Condition was effects. Salivary cortisol and sAA were collected using a passive included as a between-subject factor, and appropriate covariates drool technique with polypropylene cryovial salivettes at four were controlled for depending on the outcome of interest. time points. The first three samples were assayed for sAA, and Baseline values were controlled for to provide a more the last three samples were assayed for cortisol to accommodate conservative and unbiased estimate of between-subject for the differing secretion times of each analyte (ie, an differences in composite recovery values [44]. Post-hoc approximately 20-minute lag time for salivary cortisol secretion comparisons were conducted to examine specific pairwise into saliva compared to immediate secretion of sAA) and ensure differences when a significant effect of condition was found. that the collection timing aligned to capture measures of baseline, post-TSST, and +20 minute recovery time points. Results Experimental sessions were conducted in the afternoon (between 1 PM to 6 PM) to account for the diurnal rhythm of sAA and Manipulation Checks cortisol. Analysis of sAA from baseline (mean 85.31, SD 59.40) to Salivettes were stored at –80°C until batch analysis at the end post-TSST (mean 128.58, SD 88.53) revealed that participants of data collection at the laboratory of the Institute for displayed significant increases in sAA following the TSST Interdisciplinary Salivary Bioscience Research (University of (t =–4.78, P<.001). In addition, analysis of cortisol from California Irvine, Irvine, California). Before assaying, the baseline (mean 0.21, SD 0.11) to post-TSST (mean 0.34, SD samples were thawed for an hour to return them to room 0.24) showed that participants displayed significant increases temperature. For cortisol, all samples were assayed in duplicate in cortisol following the TSST, (t =-5.99, P<.001). Finally, by using an expanded-range high-sensitivity salivary cortisol analysis of self-reported stress from baseline (mean 22.73, SD enzyme immunoassay kit (Salimetrics, LLC, State College, 21.48) to post-TSST (mean 47.31, SD 29.37) demonstrated that Pennsylvania). The assay range of sensitivity was 0.007 to 3.0 participants displayed significant increases in self-reported stress µg/dL, and the average intraassay coefficient of variation was following the TSST (t =–7.96, P<.001). These results indicate 5.5%. For sAA, samples were tested in duplicate using a that TSST reliably increased psychological and physiological commercially available kinetic enzyme reaction assay kit stress. (Salimetrics, LLC). The assay range of sensitivity was 0.4-400 Differences in Salivary Alpha Amylase Recovery U/mL, and the average intraassay coefficient of variation was 3.3.%. Between Conditions Between-subject comparisons indicated that there was a Analytic Strategy significant main effect of condition on sAA recovery All dependent variables (self-reported stress, sAA, and cortisol) (F =3.78, P=.03; no phone: mean 10.078, SE 0.271; phone 2,133 were checked for skewness and kurtosis and transformed present: mean 10.007, SE 0.280; HRVB game: mean 9.132, SE accordingly. No transformation was performed for values of 0.266). Post-hoc comparisons revealed that those in the HRVB self-reported stress. Values of sAA were moderately skewed, game condition displayed significantly less sAA during recovery and a square root transformation was used to transform the than those in the no phone condition (t =2.48, P=.02) and the values to approximate a normal distribution. Values of cortisol phone present condition (t =2.26, P=.03). The no phone and were moderately skewed, and a logarithmic transformation was phone present conditions did not differ (t =–0.19, P=.85; used to transform the values to approximate a normal distribution. Outlying values above or below three SDs from Multimedia Appendix 2). Within-subject analyses revealed that the mean were removed. No outliers were removed for there was no significant main effect of time for sAA recovery self-reported stress, three outliers (2.1%) were removed for (F =.003, P=.96) and no significant interaction between time 1,133 sAA, and six outliers (2.8%) were removed for cortisol. and condition (F =0.081, P=.92). 2,133 Models controlled for covariates that were significantly associated with the dependent variable. Sex, time since waking, and baseline cortisol were associated with cortisol recovery and http://games.jmir.org/2019/4/e15974/ JMIR Serious Games 2019 | vol. 7 | iss. 4 | e15974 | p. 5 (page number not for citation purposes) XSL FO RenderX JMIR SERIOUS GAMES Hunter et al [52]. It should be noted that no mechanisms can be determined Differences in Cortisol Recovery Between Conditions for the lack of cortisol and self-reported stress, as we did not Although the cortisol levels declined during recovery for all find significant effects on these measures. Future studies should conditions, there was no main effect of condition on cortisol further investigate the mechanisms for why HRVB delivered recovery (F =1.19, P=.31). 2,126 via a smartphone influences stress recovery. Differences in Self-Reported Stress Recovery Between Interestingly, those who had their phones present during stress Conditions recovery did not glean any additional stress-buffering benefits Although self-reported stress declined during recovery for all beyond those with no phone. Previous work has demonstrated conditions, there was no main effect of condition on that having a phone present, but not using it, leads to steep self-reported stress recovery (F =1.42, P=.24). declines in sAA during physiological recovery from a stressor 2,133 [16]. We failed to replicate this outcome. In the study by Hunter et al [16], participants had their phones with them while Discussion undergoing the stressor. In this study, participants only had their Principal Findings phones immediately after the study. This difference in timing implies that it may be helpful to have a phone present while In this study, we examined the effect of using or having a experiencing a stressor, but it provides little to no benefit when smartphone on psychological and physiological stress reduction present during recovery. In addition, a phone may serve as a during recovery. We found that those who used an HRVB “digital security blanket” in mildly stressful situations like social training app exhibited the lowest levels of sAA during recovery. exclusion but may not exert similarly beneficial effects under Specifically, those in the HRVB game condition released less more potent stressors such as the TSST. sAA during recovery than those who had their phones present or had no phone at all. These results indicate that engaging in Limitations a brief 5-minute HRVB training session on a smartphone can There are several limitations that limit the generalizability of effectively reduce stress-related sympathetic activity, as assessed these results. First, our sample is not representative of the by levels of sAA. Although the magnitude of the effect for the population at large. The majority of our participants were change in sAA was only small to medium (η =0.05) [45], it healthy young Asian women, all of whom were iPhone users was similar to previous studies [16,46]. The sAA findings are and college educated. Since we drew our sample from a particularly important because high levels of sAA are associated university population, our participants were likely wealthier, with a range of deleterious health-related outcomes such as younger, more dependent on their phone, and more educated asthma, frequency of illness, and chronic fatigue [47-49]; than the average person. Thus, these conclusions cannot be therefore, lower levels of sAA are desirable from a health extrapolated to all populations. perspective. Our findings provide health-related information In addition, the effectiveness of Breather for influencing sAA about the use of mHealth interventions on a smartphone. Since recovery compared to the other conditions may have been delayed physiological recovery can be predictive of risk for statistically limited by differences in baseline values. Those in long-term health issues [50], we can infer that using a serious the HRVB game condition had significantly lower levels of sAA game such as Breather when recovering from a stressful at baseline. These differences may have been due to a experience may provide long-term health benefits. methodological inconsistency, as the individuals in the HRVB Our study design did not allow us to conclusively determine game condition had a slightly different experience during the the mechanisms responsible for the stress-buffering effect, but baseline period before undergoing the TSST; they spent there are several possibilities for why Breather effectively aided approximately 2 minutes receiving training on the HRVB app. in stress recovery. The most obvious explanation is that Per methodological recommendations, these baseline values undergoing HRVB training increases parasympathetic activity, were controlled for to provide a more conservative and unbiased which is typically inversely related to sympathetic indicators estimate of between-subject differences in recovery [43]. such as sAA. Thus, the low levels of sAA for those in the HRVB Without the inclusion of baseline sAA as a covariate in the game condition may be indicative of direct physiological models, there would have been greater statistical differences alterations induced by the use of Breather. In addition, between HRVB game use and the other conditions. Although psychological factors may have played a role in explaining sAA this statistical decision does limit the magnitude of our sAA recovery. The simple distraction induced by diverting cognitive recovery findings, these differences in baseline raise an attention away from ruminating thoughts about the stressor may interesting point about the ways in which Breather influences have positively contributed to the effects. Furthermore, reactions to a stressor. If, indeed, the brief training period parasympathetic activity has been associated with increases in reduced baseline sAA and sAA reactivity to the stressor, then positive valence and low arousal emotions such as calmn [24], using an HRVB serious game like Breather could possibly be which suggests that feelings of calm may have also played a an effective method for buffering stress reactivity as well as role in stress recovery. Finally, it is possible that the ability to recovery and may be an advisable activity to engage in prior to monitor stress responses via the visual interface of Breather a major stressor. Before any recommendations can be made, increased perceptions of control, which subsequently alleviated future studies should explore the optimal timing for HRVB feelings of stress. This is due to the fact that acute stress is often implementation and determine whether it is most effective induced by a perceived lack of control [51], and when that before or after a stressor. perceived control is increased, it can inhibit autonomic arousal http://games.jmir.org/2019/4/e15974/ JMIR Serious Games 2019 | vol. 7 | iss. 4 | e15974 | p. 6 (page number not for citation purposes) XSL FO RenderX JMIR SERIOUS GAMES Hunter et al Additionally, the effectiveness of Breather may have been importance of assessing both when contemplating health hindered by the way in which the participant interacted with relevance of stress or psychological outcomes [54]. Additionally, the app and understood the directions. During this training there is substantial variation based on individual factors, such period, information about the purpose of using this app (eg, this as demographics, in the association of subjective and objective activity makes you more relaxed and less stressed) was hidden measures of stress [55]. Furthermore, studies examining the from the participant in order to reduce demand characteristics convergence of self-report and physiological measures of stress and maintain internal validity across conditions. However, the have found that the assessments are highly correlated during success of biofeedback training hinges on the individuals’ the TSST, but not before or after [42]. Thus, it is not surprising perception that they are actively controlling their physiological that sAA was the only metric that yielded significant results. functions in an effort to reduce stress [8]. Without this The significant sAA finding provides valuable information understanding about the purpose of the activity, the biofeedback about how a HRVB training game via an mHealth app may aid exercise was likely less effective for the participants. In these in stress recovery; however, future studies should consider a ways, methodological constraints may have led to a more wider range of health-related outcomes. conservative effect of Breather compared to the other conditions. Finally, it should be acknowledged that the scope of this study Furthermore, user error issues that occurred within the app may did not allow us to conclusively determine whether using the have limited the effectiveness of Breather. The program requires HRVB app was more or less effective than performing other the user’s finger to be placed very precisely on the light sensor actions on one’s phone. Although past research is mixed on to monitor heart rate change. It is sometimes difficult to maintain how phone use influences stress recovery [17,18], there is great this position, and warnings pop up on the screen each time a potential for future researchers to explore how unstructured finger is placed incorrectly. Based on participant feedback, these phone use (eg, listening to music, browsing social media) could warnings made individuals feel as if they were performing impact physiological and psychological stress. Given the wide poorly, which may have induced further stress rather than variety of potential ways in which people can use their phones, alleviate it. To investigate whether user error played a role, future studies should further investigate the effects of various adherence to finger placement was assessed using metrics types of phone interactions on stress recovery. provided from the app’s database. Data showed that users had Conclusions and Implications their fingers placed correctly for approximately 96% of the time; Based on these results, one can conclude that completing HRVB however, that still means that for 4% of the session, they were training on an app such as Happify may be a practical and getting warnings telling them, “please place your finger on the effective strategy for reducing acute physiological stress. It is sensor.” This may have been bothersome and unduly reduced often not feasible to use a smartphone to buffer stress while the effectiveness of Breather, which is important to consider in undergoing a stressor, but it is practical and ecologically valid future efficacy tests and real-life applications. to use a phone immediately after one has experienced a stressful When considering a more comprehensive assessment of stress, experience. Our smartphones are conveniently with us at most conclusions from this study must be tempered by the lack of times, and thus, we have this effective stress-reducing tool at significant group differences for salivary cortisol and our disposal anytime and anywhere we need it. To further self-reported stress. Based on these discrepancies, we can only examine how smartphones can aid in stress recovery, future conclude that the HRVB game had a targeted effect on research should investigate the mechanisms underlying how a autonomic nervous system recovery as opposed to a general gamified stress-reducing app may buffer stress and how it effect on all types of biological and psychological stress compares to other ways of using a phone. This will inform future recovery. These inconsistencies in stress outcomes may be due interventions and provide recommendations for the development to a variety of reasons. First, cortisol and sAA represent activity of other stress-buffering tools that can be delivered through in different arms of the stress system and are not correlated at smartphone apps. a 1:1 level [36,53]. Numerous studies have discovered Results such as these are beginning to change the narrative about significant sAA results, but not cortisol, during stress recovery the effect of smartphones on our well-being. Although it is [37,38]. The one study that examined both biomarkers in the important to recognize the deleterious effects of these devices context of phone usage only found significant sAA effects [16]. on our lives, it may be even more critical to recognize the Our findings indicate that the HRVB training had a more robust positive potential of smartphones and begin to develop and use impact on autonomic nervous system activity (indicated by sAA technology in ways that augment well-being. Instead of simply measures), which makes sense because HRVB training hoping that individuals use technology in a beneficial manner, specifically targets fluctuations in cardiovascular activity that it is imperative that the hardware and software are designed in is intricately tied to autonomic activity [36]. In addition, the a way that facilitates positive behavior, thoughts, and intervention period was short (about 5 minutes), which may not interactions. Designing tools that take advantage of the have been enough time to impact cortisol, often viewed as a technological affordances and ubiquity of smartphones to put chronic stress marker with a delayed release [53]. The stress-reducing tools in the palm of one’s hand is a promising discrepancy between self-reported and physiological stress is strategy for finding ways for smartphones to maximize quite common in studies that assess both constructs [17,34,42] well-being. and one of the reasons many researchers argue for the http://games.jmir.org/2019/4/e15974/ JMIR Serious Games 2019 | vol. 7 | iss. 4 | e15974 | p. 7 (page number not for citation purposes) XSL FO RenderX JMIR SERIOUS GAMES Hunter et al Acknowledgments This project was funded by Happify Health. Conflicts of Interest ACP and ALW are full-time employees of Happify Health. However, all study design decisions, data collection, and analyses were performed by JFH, MSO, and SDP at the University of California, Irvine. Multimedia Appendix 1 A brief demo video of Breather on the Happify app. [MP4 File (MP4 Video), 157169 KB-Multimedia Appendix 1] Multimedia Appendix 2 Levels of salivary alpha amylase during recovery by experimental conditions. [PNG File , 27 KB-Multimedia Appendix 2] References 1. Ralph BCW, Thomson DR, Cheyne JA, Smilek D. Media multitasking and failures of attention in everyday life. Psychol Res 2014 Sep;78(5):661-669. [doi: 10.1007/s00426-013-0523-7] [Medline: 24178629] 2. Roberts JA, Yaya LHP, Manolis C. The invisible addiction: cell-phone activities and addiction among male and female college students. J Behav Addict 2014 Dec;3(4):254-265 [FREE Full text] [doi: 10.1556/JBA.3.2014.015] [Medline: 25595966] 3. Rosen LD, Lim AF, Felt J, Carrier LM, Cheever NA, Lara-Ruiz JM, et al. Media and technology use predicts ill-being among children, preteens and teenagers independent of the negative health impacts of exercise and eating habits. Comput Human Behav 2014 Jun;35:364-375 [FREE Full text] [doi: 10.1016/j.chb.2014.01.036] [Medline: 25717216] 4. Twenge JM, Joiner TE, Rogers ML, Martin GN. Increases in Depressive Symptoms, Suicide-Related Outcomes, and Suicide Rates Among U.S. Adolescents After 2010 and Links to Increased New Media Screen Time. Clinical Psychological Science 2017 Nov 14;6(1):3-17. [doi: 10.1177/2167702617723376] 5. McEwen BS, Gianaros PJ. Stress- and allostasis-induced brain plasticity. Annu Rev Med 2011;62:431-445 [FREE Full text] [doi: 10.1146/annurev-med-052209-100430] [Medline: 20707675] 6. McEwen BS. Stress, adaptation, and disease. Allostasis and allostatic load. Ann N Y Acad Sci 1998 May 01;840:33-44. [doi: 10.1111/j.1749-6632.1998.tb09546.x] [Medline: 9629234] 7. Goldenberg DL, Kaplan KH, Nadeau MG, Brodeur C, Smith S, Schmid CH. A Controlled Study of a Stress-Reduction, Cognitive-Behavioral Treatment Program in Fibromyalgia. Journal of Musculoskeletal Pain 2010 Jan 16;2(2):53-66. [doi: 10.1300/j094v02n02_05] 8. Moss D. Heart rate variability and biofeedback. Psychophysiology Today: The Magazine for Mind-Body Medicine 2004;1:4-11. 9. Free C, Phillips G, Felix L, Galli L, Patel V, Edwards P. The effectiveness of M-health technologies for improving health and health services: a systematic review protocol. BMC Res Notes 2010;3:250 [FREE Full text] [doi: 10.1186/1756-0500-3-250] [Medline: 20925916] 10. Ward AF, Duke K, Gneezy A, Bos MW. Brain Drain: The Mere Presence of One’s Own Smartphone Reduces Available Cognitive Capacity. Journal of the Association for Consumer Research 2017 Apr;2(2):140-154. [doi: 10.1086/691462] 11. Misra S, Cheng L, Genevie J, Yuan M. The iPhone Effect. Environment and Behavior 2014 Jul;48(2):275-298. [doi: 10.1177/0013916514539755] 12. Horrey WJ, Wickens CD. Examining the impact of cell phone conversations on driving using meta-analytic techniques. Hum Factors 2006;48(1):196-205. [doi: 10.1518/001872006776412135] [Medline: 16696268] 13. Gerin W, Davidson KW, Christenfeld NJS, Goyal T, Schwartz JE. The role of angry rumination and distraction in blood pressure recovery from emotional arousal. Psychosom Med 2006;68(1):64-72. [doi: 10.1097/01.psy.0000195747.12404.aa] [Medline: 16449413] 14. Master SL, Eisenberger NI, Taylor SE, Naliboff BD, Shirinyan D, Lieberman MD. A picture's worth: partner photographs reduce experimentally induced pain. Psychol Sci 2009 Nov;20(11):1316-1318. [doi: 10.1111/j.1467-9280.2009.02444.x] [Medline: 19788531] 15. Brown SL, Nesse RM, Vinokur AD, Smith DM. Providing social support may be more beneficial than receiving it: results from a prospective study of mortality. Psychol Sci 2003 Jul;14(4):320-327. [Medline: 12807404] 16. Hunter JF, Hooker ED, Rohleder N, Pressman SD. The Use of Smartphones as a Digital Security Blanket: The Influence of Phone Use and Availability on Psychological and Physiological Responses to Social Exclusion. Psychosom Med 2018 May;80(4):345-352. [doi: 10.1097/PSY.0000000000000568] [Medline: 29521885] http://games.jmir.org/2019/4/e15974/ JMIR Serious Games 2019 | vol. 7 | iss. 4 | e15974 | p. 8 (page number not for citation purposes) XSL FO RenderX JMIR SERIOUS GAMES Hunter et al 17. Rus HM, Tiemensma J. Social media as a shield: Facebook buffers acute stress. Physiol Behav 2018 Mar 01;185:46-54. [doi: 10.1016/j.physbeh.2017.12.021] [Medline: 29273455] 18. Rus HM, Tiemensma J. Social Media under the Skin: Facebook Use after Acute Stress Impairs Cortisol Recovery. Front Psychol 2017 Sep 19;8. [doi: 10.3389/fpsyg.2017.01609] 19. Hooker ED, Campos B, Pressman SD. It just takes a text: Partner text messages can reduce cardiovascular responses to stress in females. Computers in Human Behavior 2018 Jul;84:485-492. [doi: 10.1016/j.chb.2018.02.033] 20. Lin I, Peper E. Psychophysiological patterns during cell phone text messaging: a preliminary study. Appl Psychophysiol Biofeedback 2009 Mar;34(1):53-57. [doi: 10.1007/s10484-009-9078-1] [Medline: 19199025] 21. Afifi TD, Zamanzadeh N, Harrison K, Acevedo Callejas M. WIRED: The impact of media and technology use on stress (cortisol) and inflammation (interleukin IL-6) in fast paced families. Computers in Human Behavior 2018 Apr;81:265-273. [doi: 10.1016/j.chb.2017.12.010] 22. Fiordelli M, Diviani N, Schulz PJ. Mapping mHealth research: a decade of evolution. J Med Internet Res 2013;15(5):e95 [FREE Full text] [doi: 10.2196/jmir.2430] [Medline: 23697600] 23. Parks AC, Williams AL, Tugade MM, Hokes KE, Honomichl RD, Zilca RD. Testing a scalable web and smartphone based intervention to improve depression, anxiety, and resilience: A randomized controlled trial. Intnl J Wellbeing 2018 Dec 08;8(2):22-67. [doi: 10.5502/ijw.v8i2.745] 24. Lehrer PM, Gevirtz R. Heart rate variability biofeedback: how and why does it work? Front Psychol 2014;5:756 [FREE Full text] [doi: 10.3389/fpsyg.2014.00756] [Medline: 25101026] 25. Lacey BC, Lacey JI. Two-way communication between the heart and the brain. Significance of time within the cardiac cycle. Am Psychol 1978 Feb;33(2):99-113. [Medline: 637402] 26. Karemaker J, Lie KI. Heart rate variability: a telltale of health or disease. Eur Heart J 2000 Mar 15;21(6):435-437. [doi: 10.1053/euhj.1999.1969] [Medline: 10681483] 27. Del Pozo JM, Gevirtz RN, Scher B, Guarneri E. Biofeedback treatment increases heart rate variability in patients with known coronary artery disease. Am Heart J 2004 Mar;147(3):E11. [doi: 10.1016/j.ahj.2003.08.013] [Medline: 14999213] 28. Kleiger RE, Miller J, Bigger J, Moss AJ. Decreased heart rate variability and its association with increased mortality after acute myocardial infarction. The American Journal of Cardiology 1987 Feb;59(4):256-262. [doi: 10.1016/0002-9149(87)90795-8] 29. Dillon A, Kelly M, Robertson IH, Robertson DA. Smartphone Applications Utilizing Biofeedback Can Aid Stress Reduction. Front Psychol 2016;7:832 [FREE Full text] [doi: 10.3389/fpsyg.2016.00832] [Medline: 27378963] 30. Prinsloo GE, Rauch HGL, Lambert MI, Muench F, Noakes TD, Derman WE. The effect of short duration heart rate variability (HRV) biofeedback on cognitive performance during laboratory induced cognitive stress. Appl Cognit Psychol 2010 Oct 17;25(5):792-801. [doi: 10.1002/acp.1750] 31. Stein P. Washington University in St. Louis, School of Medicine. 2018. Validation of the Happify breather biofeedback exercise to track heart rate variability using an optical sensor. URL: https://happify.com/health/results/HLS-05.pdf [accessed 2019-11-11] 32. Vaschillo E, Lehrer P, Rishe N, Konstantinov M. Heart rate variability biofeedback as a method for assessing baroreflex function: A preliminary study of resonance in the cardiovascular system. Applied Psychophysiology and Biofeedback 2002;27(1). [doi: 10.1023/A:1014587304314] 33. Robins R, Fraley R, Krueger R. The self-report method. In: Handbook Of Research Methods In Personality Psychology. New York: The Guilford Press; 2019. 34. Campbell J, Ehlert U. Acute psychosocial stress: does the emotional stress response correspond with physiological responses? Psychoneuroendocrinology 2012 Aug;37(8):1111-1134. [doi: 10.1016/j.psyneuen.2011.12.010] [Medline: 22260938] 35. Hellhammer DH, Wüst S, Kudielka BM. Salivary cortisol as a biomarker in stress research. Psychoneuroendocrinology 2009 Feb;34(2):163-171. [doi: 10.1016/j.psyneuen.2008.10.026] 36. Nater UM, Rohleder N. Salivary alpha-amylase as a non-invasive biomarker for the sympathetic nervous system: current state of research. Psychoneuroendocrinology 2009 May;34(4):486-496. [doi: 10.1016/j.psyneuen.2009.01.014] [Medline: 19249160] 37. Payne LA, Hibel LC, Granger DA, Tsao JCI, Zeltzer LK. Relationship of Salivary Alpha Amylase and Cortisol to Social Anxiety in Healthy Children Undergoing Laboratory Pain Tasks. J Child Adolesc Behav 2014;2 [FREE Full text] [doi: 10.4172/jcalb.1000129] [Medline: 25525630] 38. van Veen JF, van Vliet IM, Derijk RH, van Pelt J, Mertens B, Zitman FG. Elevated alpha-amylase but not cortisol in generalized social anxiety disorder. Psychoneuroendocrinology 2008 Nov;33(10):1313-1321. [doi: 10.1016/j.psyneuen.2008.07.004] [Medline: 18757137] 39. Winslow BD, Chadderdon GL, Dechmerowski SJ, Jones DL, Kalkstein S, Greene JL, et al. Development and Clinical Evaluation of an mHealth Application for Stress Management. Front Psychiatry 2016 Jul;7:130 [FREE Full text] [doi: 10.3389/fpsyt.2016.00130] [Medline: 27507949] 40. Kirschbaum C, Pirke KM, Hellhammer DH. The 'Trier Social Stress Test'--a tool for investigating psychobiological stress responses in a laboratory setting. Neuropsychobiology 1993;28(1-2):76-81. [doi: 10.1159/000119004] [Medline: 8255414] http://games.jmir.org/2019/4/e15974/ JMIR Serious Games 2019 | vol. 7 | iss. 4 | e15974 | p. 9 (page number not for citation purposes) XSL FO RenderX JMIR SERIOUS GAMES Hunter et al 41. Allen AP, Kennedy PJ, Dockray S, Cryan JF, Dinan TG, Clarke G. The Trier Social Stress Test: Principles and practice. Neurobiol Stress 2017 Feb;6:113-126 [FREE Full text] [doi: 10.1016/j.ynstr.2016.11.001] [Medline: 28229114] 42. Hellhammer J, Schubert M. The physiological response to Trier Social Stress Test relates to subjective measures of stress during but not before or after the test. Psychoneuroendocrinology 2012 Jan;37(1):119-124. [doi: 10.1016/j.psyneuen.2011.05.012] [Medline: 21689890] 43. Lesage F, Berjot S, Deschamps F. Clinical stress assessment using a visual analogue scale. Occup Med (Lond) 2012 Dec;62(8):600-605 [FREE Full text] [doi: 10.1093/occmed/kqs140] [Medline: 22965867] 44. Overall JE, Doyle SR. Implications of chance baseline differences in repeated measurement designs. J Biopharm Stat 1994 Jul;4(2):199-216. [doi: 10.1080/10543409408835083] [Medline: 7951275] 45. Richardson JT. Eta squared and partial eta squared as measures of effect size in educational research. Educational Research Review 2011 Jan;6(2):135-147. [doi: 10.1016/j.edurev.2010.12.001] 46. Stroud LR, Foster E, Papandonatos GD, Handwerger K, Granger DA, Kivlighan KT, et al. Stress response and the adolescent transition: performance versus peer rejection stressors. Dev Psychopathol 2009;21(1):47-68 [FREE Full text] [doi: 10.1017/S0954579409000042] [Medline: 19144222] 47. Granger DA, Kivlighan KT, Blair C, El-Sheikh M, Mize J, Lisonbee JA, et al. Integrating the measurement of salivary α-amylase into studies of child health, development, and social relationships. Journal of Social and Personal Relationships 2016 Jun 29;23(2):267-290. [doi: 10.1177/0265407506062479] 48. Granger DA, Kivlighan KT, el-Sheikh M, Gordis EB, Stroud LR. Salivary alpha-amylase in biobehavioral research: recent developments and applications. Ann N Y Acad Sci 2007 Mar;1098:122-144. [doi: 10.1196/annals.1384.008] [Medline: 17332070] 49. Wolf JM, Nicholls E, Chen E. Chronic stress, salivary cortisol, and alpha-amylase in children with asthma and healthy children. Biol Psychol 2008 Apr;78(1):20-28. [doi: 10.1016/j.biopsycho.2007.12.004] [Medline: 18243483] 50. Stewart JC, France CR. Cardiovascular recovery from stress predicts longitudinal changes in blood pressure. Biol Psychol 2001 Nov;58(2):105-120. [doi: 10.1016/s0301-0511(01)00105-3] [Medline: 11600240] 51. Eysenck M. Anxiety: The cognitive perspective. London, UK: Psychology Press; 2013. 52. Leotti LA, Iyengar SS, Ochsner KN. Born to choose: the origins and value of the need for control. Trends Cogn Sci 2010 Oct;14(10):457-463 [FREE Full text] [doi: 10.1016/j.tics.2010.08.001] [Medline: 20817592] 53. Engert V, Vogel S, Efanov SI, Duchesne A, Corbo V, Ali N, et al. Investigation into the cross-correlation of salivary cortisol and alpha-amylase responses to psychological stress. Psychoneuroendocrinology 2011 Oct;36(9):1294-1302. [doi: 10.1016/j.psyneuen.2011.02.018] [Medline: 21470780] 54. Diener E, Pressman SD, Hunter J, Delgadillo-Chase D. If, Why, and When Subjective Well-Being Influences Health, and Future Needed Research. Appl Psychol Health Well-Being 2017 Jul 14;9(2):133-167. [doi: 10.1111/aphw.12090] 55. Föhr T, Tolvanen A, Myllymäki T, Järvelä-Reijonen E, Rantala S, Korpela R, et al. Subjective stress, objective heart rate variability-based stress, and recovery on workdays among overweight and psychologically distressed individuals: a cross-sectional study. J Occup Med Toxicol 2015;10:39 [FREE Full text] [doi: 10.1186/s12995-015-0081-6] [Medline: 26504485] Abbreviations HRV: heart rate variability HRVB: heart rate variability biofeedback mHealth: mobile health mHealth: mobile health sAA: salivary alpha amylase TSST: Trier Social Stress Task Edited by G Eysenbach; submitted 23.08.19; peer-reviewed by K Stasiak, D Banks, R Ciptaningtyas; comments to author 17.09.19; revised version received 10.10.19; accepted 31.10.19; published 26.11.19 Please cite as: Hunter JF, Olah MS, Williams AL, Parks AC, Pressman SD JMIR Serious Games 2019;7(4):e15974 URL: http://games.jmir.org/2019/4/e15974/ doi: 10.2196/15974 PMID: 31769761 http://games.jmir.org/2019/4/e15974/ JMIR Serious Games 2019 | vol. 7 | iss. 4 | e15974 | p. 10 (page number not for citation purposes) XSL FO RenderX JMIR SERIOUS GAMES Hunter et al ©John F Hunter, Meryl S Olah, Allison L Williams, Acacia C Parks, Sarah D Pressman. Originally published in JMIR Serious Games (http://games.jmir.org), 26.11.2019. This is an open-access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in JMIR Serious Games, is properly cited. The complete bibliographic information, a link to the original publication on http://games.jmir.org, as well as this copyright and license information must be included. http://games.jmir.org/2019/4/e15974/ JMIR Serious Games 2019 | vol. 7 | iss. 4 | e15974 | p. 11 (page number not for citation purposes) XSL FO RenderX

Journal

JMIR Serious Games – JMIR Publications

Published: Nov 26, 2019

Keywords: heart rate variability biofeedback; stress recovery; salivary alpha amylase; smartphone; mHealth

There are no references for this article.