A pilot study of trauma-sensitive yoga and Breathe2Relax among service members in an intensive outpatient program

ABSTRACT

Emerging research indicates that yoga is a promising adjunct to psychological trauma treatment. The current pilot study examined the associations between psychophysiological stress, diaphragmatic breathing (DB), and a trauma-sensitive yoga (TSY) regimen developed specifically for trauma-exposed service members in alignment with recent calls for precision in reporting therapeutic yoga protocols. Participants were 31 service members enrolled in a trauma-focused intensive outpatient program (IOP). Service members participated in a brief diaphragmatic breathing (DB) session using the Breathe2Relax (B2R) app followed by the TSY session. Heart rate (HR) and perceived stress were measured at baseline and after both the DB practice and the TSY session. We assessed Yoga and DB expectancies at baseline and post TSY. Participants also rated the acceptability and usability of the B2R app. Results of linear mixed effects regression models showed decreases in HR and perceived stress, compared to baseline, following DB (HR, b = −8.68, CI 95% = −13.34, −4.02; perceived stress, b = −1.77, CI 95% = −2.35, −1.18) and TSY (HR, b = −12.44, CI 95% = −17.15, −7.73; perceived stress b = −3.69, CI 95% = −4.29, −3.08). Higher levels of expectancies, compared to lower levels, related to stronger decreases in HR and perceived stress, particularly after TSY. Overall, participants rated the B2R usability as high; virtually all participants reported that “most would learn to use the app quickly,” and 76.6% reported that they would use it frequently.

What is the public significance of this article?—There is growing literature on the potential value of supplementing evidence-based trauma treatments with mind-body practices such as yoga and diaphragmatic breathing. Although many military intensive outpatient programs (IOPs) currently provide such adjuncts, very little research has examined their utility in producing the intended effect of psychophysiological stress reduction in this difficult to access population. The current pilot reports the results of a science-based and replicable certified trauma sensitive yoga regimen that demonstrated utility in lowering indices of psychophysiological stress among military IOP patients. The pilot also provides much needed data supporting the acceptability and usability of the Breathe2Relax app and evaluates its utility in reducing psychophysiological stress in this vulnerable population.

Introduction

Mind-body practices such as yoga are increasingly used for health promotion and emotion regulation among groups at risk for posttraumatic stress disorder (O’Shea et al., 2022; Sullivan et al., 2018; Taylor et al., 2020). Emerging empirical evidence demonstrates the potential utility of such practices for the management of stress and hyperarousal associated with psychological trauma (Burnett-Zeigler et al., 2016; O’Shea et al., 2022; Tarsha et al., 2020). Service members are at elevated risk for exposure to a range of traumatic events by virtue of the occupational and warzone hazards associated with military life (Reger et al., 2019). Consequently, some service members may develop behavioral health (BH) problems that require varied types and levels of treatment. Trauma-oriented intensive outpatient programs (IOPs) provide a more focused and multi-faceted approach to the treatment of psychological trauma compared to traditional outpatient psychotherapy (Ford et al., 2005). Such programs typically comprise a series of evidence-based psychotherapeutic practices that target complex treatment needs (e.g., Zalta et al., 2020). IOPs frequently incorporate mind-body exercises such as yoga into their programs to promote emotion regulation, stress reduction, and deeper engagement in evidence-based trauma therapies (Aideyan et al., 2020; Ford et al., 2005; Held et al., 2020; Zaleski et al., 2016; Zalta et al., 2020; see O’Shea et al., 2022 for a review).

Mind-body practices for stress management

Mind-body medicine refers to therapy approaches that focus on engaging complementary pathways between the mind and body to promote healing (Cristea et al., 2021; Cramer et al., 2018; Lang et al., 2021; Taylor et al., 2010). It is theorized that mind-body practices such as yoga activate pathways associated with health and well-being via bidirectional brain and body communication involving an integration of top-down (i.e., cognitive processing that occurs in the cortex) and bottom-up (i.e., physiological activation that influences neural and mental activities via pathways to the brainstem and cortex) processes (Taylor et al., 2010). Consistent with this conceptualization, a recent review suggests that yoga practices confer mental health benefits via complex psychological, physiological, and neurobiological processes that interact to promote reduced stress reactivity (Pascoe et al., 2021).

There are many styles of yoga (e.g., Raja, Bhakti, Kundalini, Mantra; see Belling, 2001). The focus of the current pilot was Hatha Yoga. Hatha Yoga practice pairs top-down processes such as focused attention and intention setting with bottom-up processes activated by slow breathing and sequenced body postures (Belling, 2001; Pascoe et al., 2021; Taylor et al., 2010). The crux of Hatha Yoga is the synchronization of the breath, or prana, with various poses, or asanas (Belling, 2001; Desikachar, 1995). The combination of mindful yogic movements coordinated with the breath has mood enhancing properties (Pascoe & Bauer, 2015). Diaphragmatic breathing (DB), a core component of Hatha Yoga, involves the use of slow and controlled breathing to facilitate relaxation and stress reduction by centering on the expansion of the lower abdomen to allow full and complete inhalation/exhalation (Aideyan et al., 2020; Hopper et al., 2019; Ma et al., 2017; Sovik, 2023). DB is generally an easily acquired skill; however, proper form is essential to derive maximum benefit (Aideyan et al., 2020; American Lung Association, 2023; Sovik, 2023). Some individuals may find DB somewhat difficult (e.g., those who habitually engage in chest breathing, which is more effortful and associated with the stress response), thus beginning a Hatha Yoga (hereafter denoted as “yoga”) session with DB instruction and a few minutes of practice may be helpful (Sovik, 2023). Combining different types of mind-body exercises is common in focused BH programs (e.g., Steele et al., 2018, University of Washington Health [UWHealth], 2023).

Physiological and psychological factors

Psychophysiological relaxation plays a vital role in the transformation of mind-body practices into useful techniques for stress reduction (Busch et al., 2012). An intended effect of yogic practices is a physiologic response that includes more efficient carbon dioxide and oxygen exchange, lowered HR and blood pressure and reductions in perceived stress (Jerath et al., 2006; Telles et al., 2004). Previous research suggests that yoga attenuates stress through the restoration of the body’s autonomic balance by lowering HR, respiration, and other physiological processes, which in turn suppresses the release of stress hormones such as cortisol and epinephrine (Gothe et al., 2016). With regular practice, yoga appears to engender physiological and neurobiological benefits including increased vagal tone, changes in brain structure and function, and overall increased capacity to manage stress (Pascoe et al., 2021). Porges’s (2007, 2009, 2011) polyvagal theory (PVT) provides a compelling neurophysiological explanatory framework for conceptualizing the mitigating influence of mind-body practices such as yoga on autonomic processes associated with traumatic exposures and other serious problems (Kolacz et al., 2019; Porges, 2007, 2011; Sullivan et al., 2018). Briefly, PVT posits that phylogenetic processes associated with the development of the mammalian autonomic nervous system produced neurophysiological substrates associated with distinct behavior responses and coping strategies (Porges, 2009). A key tenet of PVT is that physiological state influences the types of behavioral and psychological coping strategies that can be accessed at any given time.¹

There is some evidence that expectancies – the tendency for an individual to expect a given result and consciously or unconsciously exhibit that result – influence the ability to achieve a relaxed psychophysiological state through mind-body practices (i.e., the placebo effect; Hicks et al., 2016). Mind-body practices have been described as “an effective form of intentional placebo without deception” because such practices use intention to heal (Hicks et al., 2016; Kaptchuk et al., 2010). Some research indicates that low expectancies are associated with an inhibited onset of relaxation (Delmonte, 1985; Stefanek & Hodes, 1986), whereas other research indicates mind-body practices promote relaxation independent of expectancies (Hicks et al., 2016). In brief, the extent to which expectancies may influence relaxation associated with mind-body practices is not clear.

Gaps in the literature

Yoga is becoming recognized as a therapeutic technique that is defined by professional standards of education, practice, and accreditation (Aideyan et al., 2020; International Association of Yoga Therapists [IAYT], 2023). Mind-body practices such as yoga are increasingly recommended as an adjunct to psychotherapeutic treatment to improve treatment outcomes and mitigate dropout from empirically validated therapies (Hilton et al., 2019; O’Shea et al., 2022; Pascoe et al., 2021; West et al., 2017). However, much of the literature on this topic is anecdotal (Aideyan et al., 2020). As such, the lack of research examining component aspects of integrated therapeutic programs such as IOPs limits our understanding of how mind-body adjuncts enhance therapeutic outcomes (O’Shea et al., 2022). There is also significant heterogeneity in the practice and reporting of yoga in research (Sullivan et al., 2018). As a result, there is a call for specificity about the form of practice implemented, with what guidance, and under what conditions (Aideyan et al., 2020; Taylor et al., 2020).

BH venues in the military have begun incorporating use of mind-body practices such as DB and yoga for stress management (Herman et al., 2017). For example, using single-group pretest-posttest design, Steele et al., (2018) evaluated an intensive 7-day treatment program for veterans, which consisted of evidence-based trauma therapy supplemented by yoga, equine assisted psychotherapy, and narrative writing. Results of the overall program showed significant decreases in indices of distress, however, the effects associated with each type of intervention were not captured. Moreover, research on mind-body interventions as a supplement to trauma therapy is in its infancy (O’Shea et al., 2022), and very little research has focused on military IOPs. It is very difficult to engage this population in research, in part, because IOPs have very structured programs with at-risk patients. An initial evaluation of an IOP for psychological trauma using a retrospective case-series design indicated that posttraumatic stress symptoms abated following engagement in the program’s trauma groups (Hoyt et al., 2018). We were interested in adding to this literature by conducting a preliminary examination of the extent to which trauma sensitive yoga (TSY) is associated with its intended goal of decreasing sympathetic activation and stress among this beneficiary population using methods that were non-disruptive and complementary to the IOP treatment protocol.

Current investigation

IOP patients may benefit from DB and TSY practice to promote improved autonomic and BH functioning via targeted sequences of slow body movements and breathing methods designed to induce psychophysiological relaxation. The purpose of the current investigation was to conduct a pilot study to assess the utility of DB and TSY as treatment adjuncts for stress reduction among trauma exposed IOP patients.

We developed a standardized TSY regimen to engage the ventral parasympathetic nervous system for the promotion of relaxation (Porges, 2011; Sullivan et al., 2018). The regimen was based on the principles of PVT (Porges, 2011; Sullivan et al., 2018), which have been incorporated into a TSY training program geared to the needs of trauma exposed service members and veterans, TSY for Warriors (YogaFit International, 2023). We documented the TSY regimen, its duration, and setting, with recommendations from a recent meta-analysis of therapeutic yoga that underscores the value and need to explicitly describe yoga research protocols (Taylor et al., 2020; see Table 1). Participants were service members enrolled in a trauma focused IOP. We evaluated changes in perceived stress and HR following a single DB practice session facilitated with the Breathe2Relax (B2R) app and after a TSY regimen. To examine the extent to which a placebo effect may be associated with physiological relaxation and stress perception, we assessed patient expectancies associated with these practices (Hicks et al., 2016; Kaptchuk et al., 2010). We hypothesized that DB and TSY would be related to lower levels of perceived stress and HR but did not proffer hypotheses about the influence of expectancies, given the inconsistencies in the literature (Delmonte, 1985; Hicks et al., 2016; Stefanek & Hodes, 1986).

Table 1.

Yoga sequence.

Posture Type	Description	Time in Minutes
Restorative – warm-up	Focused awareness of breath exercise (on back with block supporting hips and bent knees with feet flat on the floor observing rise and fall of breath with fingertips placed on lower abdomen)	3
Vinyasa1 – warm-up	Knee-to-chest movements on back, alternating sides (with block supporting hips)	2
Twist – warm-up	Alternating supine spinal twists	1
Vinyasa – warm-up	Rocking tuck to massage spine	1
Warm-up	Supine knee-to-chest stretches	3
Vinyasa	Seated arm and shoulder stretch flow	1
Vinyasa	Modified plank flow	1
Vinyasa	Flowing Cat-cow pose (stretches torso, and spine)	1
Balancing	Balancing table pose (lengthens spine, improves balance, coordination, focus)	4
Twist	Child’s pose with side-to-side shoulder twists	1
Vinyasa	Flowing stretch alternately bending knee and extending forward and back, flowing modified warrior 1 pose, ending with pigeon pose followed by modified slide plank	7
Standing	Half-moon pose (stretches shoulders, back, and torso)	1
Standing, balancing, forward bend	Pyramid pose (deep forward fold to stretch hips and hamstring muscles and lengthen spine)	3
Seated Forward Bend	Extension of top half of body over lower half with flexed toes to stretch back (with block beneath knees for support)	1
Twist	Seated hip cradle pose (hip opening exercise to stretch hamstring muscles)	2
Backbend	Reverse plank pose (to strengthen core and lower back)	1
Inversion	Bridge pose (lifting hips and sternum while pressing arms to floor to stretch neck, spine, and hips)	1
Restorative	Corpse pose (lying on back with arms at 30 degrees from the body, palms up)	6
Total		40

¹Vinyasa denotes breath-linked movement of pose (Gard et al., 2014).

A secondary purpose of the pilot was to evaluate the usability and acceptability of the B2R app and to assess whether it reduces psychophysiological activation in a relevant group of service members. B2R is an app designed by military psychologists and software developers at the Department of Defense’s former National Center for Telehealth and Technology. B2R is a transportable tool that is intended to complement the high operational tempo of military life and typically technology intense lifestyle of service members (see Bush et al., 2019). This interactive app provides self-guided DB instruction and educational information that can be accessed outside of treatment settings (Luxton et al., 2014). Although B2R has been included in a number of previous protocols (e.g., Hoffman et al., 2019), its acceptability and usability has not been evaluated among service members receiving specialty BH treatment.

Method

Participants

Participants were 31 service members enrolled in a trauma focused IOP at a large military base. The IOP is a daily (Monday-Friday) 4-hour treatment program delivered over four-to-six weeks (see Hoyt & Staley Shumaker, 2021; Hoyt et al., 2018). This program provides treatment for service members who have experienced psychological trauma and other serious BH problems.

The average patient age was 27.0 years (SD = 6.68), ranging from 19 to 45 years. Twelve participants (38.7%) were female and 18 (58.1%) identified as non-Hispanic white. Eleven (35.5%) were high school graduates or had received a general equivalency diploma, 11 (35.5%) completed some college, five (16.1%) earned a bachelor’s degree, two (6.5%) earned associate degrees, and the remaining two participants earned a master’s degree (3.2%) and an advanced degree (i.e., MD or Ph.D., 3.2%). Equal proportions of participants were married (n = 13, 43.3%) and never married (n = 13, 43.3%); four (13.3%) were divorced. Twenty-one participants (67.7%) had attempted DB before; all had tried yoga before.

Pilot design

We used a within-subjects pre-post design. Participants completed the measures of perceived stress and HR at three time points: at baseline, immediately following the DB exercise and immediately after completion of the TSY session. Measures of DB and TSY expectancies were assessed at baseline and following the TSY session (Figure 1). The hospital’s Institutional Review Board approved all study procedures.

Figure 1.

Sequence of procedures.

Procedures and setting

All patients enrolled in the IOP were eligible for participation via a rolling enrollment procedure. IOP patients were approached by research coordinators during down time (e.g., beginning or end of IOP therapeutic groups), who explained the purpose of the pilot and invited the patients to volunteer for participation. Each participant received an information sheet containing details about the pilot.

We conducted pilot activities in the early morning prior to other IOP activities in a quiet, secluded area of the clinic. A research assistant greeted pilot participants at the appointed time and asked them to complete a questionnaire containing demographic information including age, sex, race/ethnicity, educational attainment, and relationship status. Participants received individual instruction on how to palpate and record their HR. They completed baseline measures of perceived stress and DB and TSY expectancies.

Next, following a brief introduction and demonstration of the app by a research assistant, participants engaged in a DB practice session via the B2R app on iPads. Participants received a complimentary pair of headphones to use with the iPad during a six-minute DB practice accompanied by music and visual scenery (available on the app) selected by participants. Participants recorded their post DB measures of HR and perceived stress immediately after the B2R practice session. Following the B2R session, participants began the 40-minute TSY session. The yoga facility was characterized by diffused natural light and accompanied by relaxing music and the sound of slow ocean waves taken from the BetterSleep: Relax and Sleep Calm Sounds, Meditation, Music app (https://apps.apple.com/us/app/bettersleep-relax-and-sleep/id314498713). The setting was consistent across the pilot.

The standardized TSY sessions consisted of a variety of stationary and moving yoga positions designed to engage the ventral parasympathetic nervous system (Table 1; Porges, 2011). The TSY instructor invited the participants to engage in the sessions, encouraging them to move in a fluid, expansive manner suited to their needs and individual cadence, consistent with specialized training recommendations for this population (Yogafit International, 2023). HR, perceived stress, and the B2R app’s acceptability and usability was assessed immediately following the TSY session.

TSY choreography

The TSY sequence was choreographed in line with the principles of PVT (Porges, 2011) in collaboration with a health psychologist with expertise in Kundalini Yoga and more than 20-years’ experience (second author). Prior to the commencement of the pilot, we piloted the TSY sequence and received the endorsement of two military psychologists as well as an advanced yoga therapist. We made adjustments, as indicated, to maximize impact and uptake among the targeted group of service members.

The pilot TSY instructor (first author), a clinical psychologist with prior experience facilitating TSY groups with service members in military based IOPs as well as first responder and special needs persons, is trained and certified in TSY For Warriors (YogaFit International, 2023). The TSY for Warriors program was designed by a former Army military officer with expertise in Hatha Yoga (YogaFit, 2023). The program focuses on sensorimotor techniques to address physical and emotional symptoms at the autonomic level via coordinated sequences of slow body movements and deep breathing. YogaFit has the endorsement of the Yoga Alliance, a nonprofit organization that sets standards for an ethical and educational framework for yoga instructors to ensure high quality, safety, and accessibility (Yoga Alliance, 2023).

Measures

HR

To assess HR, service members were instructed how to palpate their carotid artery for 30 seconds (timed by the research coordinator) and to multiply the heartbeats by two to obtain the HR/minute metric. This self-assessment method has been shown to be a reliable and valid way to measure heart rate (Da Silva, 2012).

Perceived stress

Participants rated their perceived stress at baseline and following the DB and TSY practices using a standard 10-centimeter visual analogue scale (VAS) ranging from “stressed” to “relaxed.” A research assistant presented participants with a form containing a line denoting “relaxed” and “stressed” at opposite ends and asked them to indicate the level of stress they were experiencing at that time by placing a vertical line at the relevant location. VAS measurement has demonstrated construct validity in comparisons with the Perceived Stress Scale (Ezzati et al., 2014; Lesage et al., 2012).

Expectancies

We assessed expectancies associated with DB and TSY with three statements that participants were asked to rate on a 10-point scale ranging from “Definitely” to “Definitely Not:” 1) “I believe I can learn techniques to manage my stress;” 2) “Diaphragmatic breathing will be helpful in managing my stress;” and 3) “Yoga will be helpful in managing my stress.” Baseline expectancy items were moderately correlated. Thus, a single factor score was derived (using regression) from the three baseline expectancy items. The questionnaire also asked participants if they had tried DB or yoga previously (yes/no). We assessed expectancies at baseline (i.e., prior to DB) and following the TSY session. Coefficient ω of the composite score was 0.66.

Acceptability and usability of B2R

System Usability Scale 2 (SUS) is a ten-item attitudinal Likert-type scale (5 points; 1 = strongly disagree, 5 = strongly agree) that provides a global view of subjective assessments of acceptability and usability and has been used to evaluate numerous mobile apps (e.g., Hyzy et al., 2022; Kaya et al., 2019). The SUS is an industry standard that is referenced in over 500 publications (Sauro, 2011). Internal consistency reliability of the observed score for this sample was 0.92.

Statistical methods

We used linear mixed effects regression models to analyze change in HR and perceived stress after both DB and TSY. Models were estimated using restricted maximum likelihood with Kenward-Roger degrees of freedom for t-distribution values to construct 95% confidence intervals around model point estimates (Kenward & Roger, 1997). Time was specified categorically with terms for post-DB and post-TSY in reference to baseline. Random intercepts were included in the models. The baseline expectancy value was included as a covariate in the regression models for both the intercept and slope parameter estimates. All models were estimated using Stata 14 (StataCorp, 2015).

Results

Expectancies

Mean baseline expectancy scores for the three items were (I believe I can learn techniques to manage my stress: M = 8.13, SD = 1.52; Diaphragmatic breathing will be helpful in managing my stress: M = 7.20, SD = 1.89; Yoga will be helpful in managing my stress: M = 7.94, SD = 1.73). This suggests that participants had both high overall expectations that they could learn stress-reduction skills, as well as high expectations about the helpfulness of DB and yoga to manage their stress.

HR

Mean baseline heart rate was 85.19 beats per minute (SD = 18.71). We present the results of the linear mixed-effects regression models in Table 2. We excluded one participant from the analysis for having an extreme outlier at baseline (154 heartbeats per minute). Average HR was lower after both DB (d = −0.62) and TSY (d = −0.89) compared to the baseline assessment. The point estimate for HR after TSY was lower than for after DB (b = −3.77, 95% CI = −8.47, 0.94; d = −0.27); additional research is required to confirm this finding. Participants with higher baseline expectancy had higher baseline HR scores, and higher expectancy scores were associated with stronger decreases in HR, particularly for TSY (d = −0.48).

Table 2.

Mixed effects regression models analyzing changes in heart rate and perceived stress associated with DB and TSY compared to baseline.

	Heart Rate (n = 30)		Perceived Stress (n = 31)
	Estimate	95% CI	Estimate	95% CI
Intercept	82.79	78.38, 87.20	6.88	6.25, 7.52
Expectancy	6.24	0.81, 11.67	0.45	−0.34, 1.25
Slope
Post DB	−8.68	−13.34, −4.02	−1.77	−2.35, −1.18
Post DB x Expectancy	−3.12	−8.86, 2.61	−0.64	−1.37, 0.09
Post yoga	−12.44	−17.15, −7.73	−3.69	−4.29, −3.08
Post TSY x Expectancy	−6.62	−12.54, −0.69	−1.68	−2.44, −0.93

Models were estimated using restricted maximum likelihood with Kenward-Roger degrees of freedom for t-distribution values to construct 95% confidence intervals around model point estimates. DB = diaphragmatic breathing; TSY = trauma-sensitive yoga.

Perceived stress

Average perceived stress at baseline was 6.88 (SD = 1.75). This value decreased after both DB (d = −1.01) and TSY (d = −2.11), compared to baseline. Perceived stress scores post TSY were lower than post DB (b = −1.92, 95% CI = −2.52, −1.32; d = −1.10). While expectancy was not strongly associated with baseline scores, there was a stronger decrease in perceived stress scores among participants with higher expectancy values. This was particularly noteworthy after TSY (d = −1.10).

Acceptability and usability of B2R

Thirty participants completed the SUS item set. At the item level, the responses were consistent with the valence of the wording for each item. The median score was 4.4 (inter-quartile range = 0.7). This suggests that most participants found the app easy to use and were satisfied with the content, as displayed in Table 3. Most participants reported few experienced or anticipated technical problems with app usage and virtually all reported that “most would learn to use the app quickly” (i.e., reported a score of 3 or higher on the 5-point scale; Table 3). The two items that had noticeable endorsement across the response range were, “I would like to use this app frequently,” and “the functions were well integrated.”

Table 3.

B2R acceptability and usability as rated on the system usability scale.

	1 Strongly Disagree	2	3	4	5 Strongly Agree
Item	%	%	%	%	%
I would like to use this app frequently	6.7	16.7	30.0	23.3	23.3
App unnecessarily complex	63.3	13.3	16.7	3.3	3.3
App was easy	0.0	6.7	10.0	30.0	53.3
Need support of tech person	90.0	3.3	6.7	0.0	0.0
Functions well integrated	6.9	10.3	27.6	34.5	20.7
Too much inconsistency	58.6	24.1	0.0	13.8	3.5
Most would learn to use app quickly	0.0	0.0	6.9	24.1	69.0
App cumbersome to use	50.0	13.3	6.7	16.7	13.3
Confident using the app	10.0	6.7	6.7	26.7	50.0
Need to learn a lot before I could get going with the app	63.3	13.3	6.7	6.7	10.0

n = 30.

Discussion

The primary purpose of this pilot study was to examine the utility of a customized TSY routine and DB practice session in reducing psychophysiological stress among service members enrolled in a trauma focused IOP program. Our findings indicate that the TSY routine and B2R show promise as treatment adjuncts among at-risk service members in IOPs for trauma exposure. We observed significant reductions in HR and perceived stress following both the DB and TSY session compared to baseline. These results are consistent with research indicating that yoga practice is associated with reductions in perceived stress and down-regulation of sympathetic arousal (Bukar et al., 2019; Sengupta & Krajewska-Kulak, 2013). In addition, our findings add to the growing literature on the potential benefits of mind-body treatment adjuncts to BH care (O’Shea et al., 2022).

A secondary purpose of our pilot was to evaluate the acceptability and usability of the B2R app. User experience testing is essential to obtaining satisfactory user outcomes and impact (Kaya et al., 2019; Lau et al., 2020; Varghese & VandenBos, 2019). A recent review of 1009 psychosocial wellness and stress management apps found that only 2% of the apps had published peer-reviewed evidence of usability and/or efficacy; of these, the majority had just one publication (Lau et al., 2020). Our evaluation of B2R adds a key and foundational dimension that was lacking in earlier studies on this app (Hoffman et al., 2019; Luxton et al., 2014; Varghese & VandenBos, 2019) and demonstrated that all pilot participants perceived B2R to be easily learned, and 76.7% expressed an intention to use it frequently in the future. A fruitful next step would be to examine the use of the B2R over a longer period and to assess the extent to which the app facilitates regular and proper engagement in DB, relates to improvements in stress management emotion regulation and serves as a useful adjunct to trauma focused therapies.

It is interesting that service members with higher expectancies experienced higher reductions in HR and perceived stress compared to service members with average expectancies. This finding is consonant with research indicating mind-body based practices are in effect an “intentional placebo” (Hicks et al., 2016; Kaptchuk et al., 2010). It may be that those who volunteered for the pilot had previously experienced benefits from yoga and thus had high expectancies with respect to TSY. Given that those with the greatest drop in HR and perceived stress also had higher than average expectancies, this finding may represent regression to the mean. It is also conceivable that those experiencing the greatest levels of psychophysiological arousal were more strongly seeking stress relief and therefore had higher DB and TSY expectancies. Alternately, this finding could be an artifact of the small sample size.

A particular strength of our pilot is that we carefully documented the regimen, consistent with recent calls for specificity in reporting of mind-body interventions to help set the groundwork for future work in this area (Aideyan et al., 2020; Sullivan et al., 2018). The current heterogeneity of practice and insufficient detail about how, where, when, and under what conditions therapeutic yoga is practiced limits the development of testable hypotheses and clinical applications that can advance a broader understanding of the types of interventions that are most suitable for traumatized individuals and underlying mechanisms involved in therapeutic yoga practices (Sullivan et al., 2018). Our study also adds to the newly emerging literature on the supplementation of evidenced-based treatments (e.g., cognitive-behavioral therapy) with mind-body interventions (O’Shea et al., 2022).

The limitations of this pilot should also be noted. The two interventions used in this study were provided in a fixed sequence for all participants. Consequently, it is not possible to separate intervention order from the results reported here. There was also no comparator group receiving either no intervention or an alternative form of yoga. As such, it is unknown to what extent alternative approaches to yoga, including sham, would produce corresponding reductions. In addition, there may be selection bias, as the service members who volunteered for the pilot may have been individuals who view yoga in a particularly favorable light, as evidenced by the relatively high expectancy endorsement and previous experience with yoga. Finally, the measures of perceived stress and expectancy were self-reported and combining the three expectancy items only resulted in a measure of modest internal consistency reliability. To the extent that expectancy affects actual changes in perceived stress or only the way in which these self-report measures are used is unclear.

Despite these limitations, the present pilot addresses initial gaps in the current literature (Aideyan et al., 2020; Sullivan et al., 2018; Zalta et al., 2020). We successfully executed our pilot in a very difficult to reach population for whom little data exists. Using a replicable and science-based approach (Porges, 2011), we demonstrated the potential utility of controlled, slow breathing techniques and corresponding bodily movement for optimizing psychophysiological processes to promote relaxation (Aideyan et al., 2020; Russo et al., 2017) among trauma exposed IOP patients. Further evaluation within and across populations is needed, and we hope that the current pilot will stimulate further investigation in this area.

Conclusions

Overall, our results represent an initial demonstration of the utility of a TSY routine grounded in the principles of PVT (Porges, 2011) in reducing perceived stress and HR (i.e., via a six-minute DB exercise and/or 40-minute TSY session) in this population of service members. Such findings, though provisional, suggest that trauma exposed IOP patients can experience stress reduction in a relatively short period of time, which may go a long way toward reinforcing engagement in DB and TSY after program discharge. Moreover, regular practice of DB and yoga may be beneficial to the long-term development of stress management and emotion regulation skills (Held et al., 2020; O’Shea et al., 2022; Zaleski et al., 2016, ; Zalta et al., 2020).

There are also some noteworthy advantages associated with mind-body practices such as DB and TSY. Both can be practiced at home and are self-reinforcing and non-pharmacologic. Service members can incorporate these practices into their lifestyles at no cost and continue to build this skillset across the lifespan. These practices furthermore are complementary to other behaviorally based emotion regulation strategies and, with consistent use, may have the capacity to address several problem areas (e.g., stress, sleep, and over-medication) that may affect trauma-exposed individuals (e.g., Held et al., 2020; O’Shea et al., 2022; Zaleski et al., 2016; Zalta et al., 2020). As treatment adjuncts, TSY and DB may allow traumatized individuals to participate more fully in evidence-based trauma treatments by attenuating the emotion dysregulation that often interferes with treatment engagement (Held et al., 2020; O’Shea et al., 2022; Zaleski et al., 2016; Zalta et al., 2020).

Additional research on this topic is required to extend the current findings and their applicability to trauma focused IOPs and other treatment settings. For example, integration of mind-body practices into conventional medicine may prove useful to supporting recovery from psychological trauma (Russo et al., 2017). Investigation of the biological pathways and mechanisms of action is also needed to expand our understanding of stress-related disorders and diseases (Pascoe et al., 2021). The activation of such processes may support psychophysiological health, potentially preventing or interrupting related disease progression among vulnerable individuals (Russo et al., 2017).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Disclaimer

The opinions and assertions contained herein are the private views of the authors and are not to be construed as official or reflecting the views of the Department of the Army or the Department of Defense.

Data availability statement

The data used in this study are available upon request.