Abstract
Objective:
Despite evidence of spirituality's protective benefits against psychological and physiological sequelae of stress, research has yet to provide empirical support for biological mechanisms of spiritually integrated interventions, thus limiting implementation in evidence-based Integrative Medicine approaches to illness. This study aims to provide evidence of physiological improvements in stress reactivity and recovery across the delivery of a spiritual–mind–body (SMB) intervention.
Methods:
This study examines heart rate variability (HRV) and self-report data collected before and after the delivery of a targeted preventive 8-week SMB wellness intervention (Awakened Awareness for Adolescents [AA-A]) to a nonclinically referred sample of emerging-adult undergraduates of a highly rigorous urban university. Participants (N = 68; mean age = 19) completed HRV collection across 5-min rest, stress, and recovery phases before and after delivering AA-A. Participants also completed a battery of validated self-report wellness and mental health measures, including the Patient Health Questionnaire (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), PTSD Civilian Checklist (PCL-C), Spiritual Transformation Scale (STS), and the Difficulties in Emotion Regulation Scale (DERS).
Results:
Significant improvements in high-frequency HRV, low-frequency HRV, and the high-low-frequency ratio were observed across recovery periods. Post-intervention recovery HRV was associated with changes in PTSD symptoms, spiritual decline, and emotion regulation. Significant regression models supported associations between improvements in postgroup HRV and improvements in emotion regulation and spiritual decline.
Conclusions:
These findings suggest that AA-A may support a spiritual and psychological recovery process that promotes psychophysiological resilience from stress in emerging adult college students. Assessing spiritual functioning and applying spiritually integrated interventions may support healing across spiritual, psychological, and physical domains. This line of inquiry warrants further investigation to fully understand the role of spiritual and psychological recovery in physiological resilience and recovery from stress.
Background
Integrative medicine (IM) models are beginning to recognize that mind–body healing can be envisioned as the alignment of the body with the spirit.1–3 Here, spirituality is conceptualized based upon previous research as fostering transcendent awareness, a form of perception that carries an inner sense of a consistent, bidirectional relationship with a Higher Power/Transcendent to inform one's daily meaning and purpose in a perceived sacred world. 4 Within IM, spirituality has been included as one path to alleviate emotional suffering in the face of physical illness. 3 Spiritual well-being has also been found to contribute to physical well-being. For example, multiple longitudinal studies show that highly spiritual individuals experience less cardiovascular disease, live longer, and survive congestive heart failure longer than less spiritual individuals.5–7 However, spiritually integrated interventions have not typically been incorporated into the IM cannon of integrative approaches to healing from physical ailments, partly due to reliance on self-report data and lack of experimental and multimodal assessment of stress regulation that provides rigor to other well-tested evidence-based IM interventions.8–10 Thus, additional research on biopsychological mechanisms between spiritually integrated interventions and health is needed.
Proposed biological mechanisms of mind–body interventions to improve stress regulation within the umbrella of IM (i.e., biofeedback, Tai Chi, and yoga) include improvements in sympathetic nervous system reactivity and recovery and balance of sympathovagal response.8–11 Heart rate variability (HRV) has been utilized as a peripheral measure of this autonomic nervous system activity. It is linked with psychological processes that promote mental health, such as emotion regulation, mindfulness, and psychological flexibility.12–14
Within mind–body intervention research, change in HRV has been linked to change in primary psychological outcomes, 15 providing proof-of-concept that mind–body interventions can promote change in physiological biomarkers associated with stress. Further, there is evidence that this relationship is bi-directional, with change in psychophysiology encouraging change in psychological well-being and vice versa. Thus, psychophysiological data have been used as secondary or primary outcomes in treatment development research.16–19
The physiology undergirding mind–body well-being may be more adequately explained by conceptualizing a spiritual–mind–body (SMB) connection, as spiritual individuals are more likely to engage with IM than nonspiritual individuals.20,21 A recent systematic review of experimental studies shows that spiritual practices such as prayer promote healthy neurocognitive and physiological functioning. 22 The bi-directional nature of this relationship is supported by biofeedback studies showing that spiritual experience induces optimal HRV, and optimal HRV induces self-report of transcendence and interconnectedness.23,24 It has been suggested that SMB interventions may capitalize on the understudied phenomenon of spiritual experience promoting sympathovagal balance and autonomic regulation, 25 explaining the prospective link between spirituality and cardiovascular health. However, this has yet to be tested using an ecologically valid stress induction in a prepost design of an SMB intervention.
Given reports over the past 5 years of alarming rates of psychopathology and stress-related illness in undergraduates aged 18–25,26–28 it is imperative to identify targeted interventions to improve subjective well-being and signals of stress regulation to increase resilience and reduce downstream effects of poor functioning and health. The current data come from a larger study that demonstrated significant improvements in the level of posttraumatic stress (PTS) symptoms, depressive symptoms, and measures of psychological and spiritual well-being across the delivery of Awakened Awareness for Adolescents (AA-A). 29 Our findings at the initial assessment of AA-A indicate an elevated level of Spiritual Decline, a weakening of spiritual association with world view, goals, sense of self, and relationships, among college students with a lifetime report of two or more traumatic events. 30
AA-A is an SMB intervention consisting of 8 weekly 90-min sessions that scaffold enhanced spiritual perception alongside widely accepted contemplative, meta-cognitive, and relational techniques. AA-A engenders a perceptual shift from a narrow “achievement awareness” that values external accomplishments and goals to the development and cultivation of an expansive “awakened awareness,” a spiritual perspective of the inherent connection to one's higher self and Higher Power/Transcendent. Fundamental to AA-A are practices and skills such as (1) guided meditation, (2) guided spiritual visualization, (3) peer group and dyadic sharing exercises, and (4) self-reflection and development of a spiritual dialectical stance, that is, coping alongside a perception of a higher self, Higher Power/ultimate life force (within or outside of a faith tradition). Group sessions are guided by two group leaders working within a progressive framework of (1) grounding meditation practice; (2) written reflection about the meditation practice and the previous week's material; (3) didactic on weekly content; (4) experiential contemplative practice related to didactic; (5) dyad sharing (6) leader guided group reflection (7) closing meditation.
To provide experimental evidence that spiritual and physiological well-being are inextricably linked and to examine SMB wellness interventions at the level of rigor as IM approaches with psychophysiological outcomes, we investigate changes in HRV using an experimental stress-induction task among emerging adult undergraduates completing the AA-A intervention and link outcomes in HRV with changes in clinical, psychological, and spiritual well-being. We hypothesize that (1) psychophysiological stress response will improve across the delivery of an 8-week SMB wellness intervention; (2) outcomes in psychophysiological data will be associated with a change in clinical, psychological, and spiritual well-being self-report.
Methods
Participants and procedures
The open trial was conducted in residential hall lounges on two undergraduate sister campuses as part of a larger study examining feasibility, acceptability, and changes in clinical, psychological, and spiritual well-being characteristics across the AA-A intervention. This intervention and participant data are described elsewhere. 29 Participants (total N = 77) were enrolled students between 18 and 25 years of age, recruited through tabling and flyering throughout the residential halls at the two undergraduate campuses. Exclusionary criteria included previous participation in the AA-A intervention. Respondents were assessed before and after the delivery of AA-A and compensated with Amazon gift cards based on the number of assessments completed. The Institutional Review Board (IRB) of Teachers College, Columbia University, approved this study and related protocols.
At pregroup assessment (T1), participants completed informed consent, a stress induction exercise alongside collection of HRV, and a digital survey including self-report measures of clinical, psychological, and spiritual well-being. The participants then attended 8-weekly, 90-min group sessions of AA-A. Participants completed postgroup data collection (T2) the week after the final (8th) group session. Nine individuals had HRV data lost due to technological problems (e.g., data did not transfer; the device dropped too many data points to consider data reliable). Thus, 68 AA-A participants' data were examined in this study.
Measures
Clinical measures
Anxiety symptoms were assessed using the Generalized Anxiety Disorder-7 (GAD-7) questionnaire. 31 This well-validated 7-item measure assesses clinical symptoms of general anxiety over the past 2 weeks. Items are anchored on a Likert scale from not at all (0) to nearly every day (3). Symptoms of depression were assessed using the Patient Health Questionnaire (PHQ-9). 32 The PHQ-9 is a 9-item scale that reflects the severity of depressive symptoms over the past 2 weeks. Items are anchored on a Likert scale from not at all (0) to nearly every day (3). The PHQ-9 has evidence of high internal consistency (Cronbach's α = 0.86–0.89). PTS symptoms were assessed using the 17-item PTSD Civilian Checklist (PCL-C). 33 A total symptom severity score (range = 17–85) can be obtained by summing the scores from all items, with response options ranging from not at all (1) to extremely (5).
Affective and cognitive measures
Difficulties in Emotion Regulation Scale (DERS) 34 is a well-validated, 36-item self-report measure for assessing emotion regulation problems among adolescents and adults and has high internal consistency (α = 0.93). Higher scores indicate greater difficulties with emotion regulation. Freiburg Mindfulness Scale (FMS) 35 is a validated 14-item self-report measure for assessing trait mindfulness. The FMS has high internal consistency (α = 0.93). Scores range from 14 to 75, with higher scores indicating greater mindfulness.
Spiritual well-being measures
The Spiritual Transformation Scale (STS) 36 was developed to assess changes in spirituality as a response to life events, such as illness. The scale includes Spiritual Growth and Spiritual Decline subscales and was adapted to reflect nonillness-related changes from the beginning of AA-A. The STS showed high internal consistency within this sample (α = 0.96). Higher scores on the subscales indicate higher levels of each construct. For example, high scores on the Spiritual Decline subscale indicate greater distress related to preexisting spiritual beliefs (e.g., “I feel I've lost some important spiritual meaning that I had before.”) The Spirituality Scale 37 is well validated and assesses the human spiritual dimension. Higher scores on the 23-item scale represent higher levels of spirituality.
Heart rate variability
Heart rate data were collected in a group setting using the emWave Pro handheld device and analyzed using Kubios HRV version 3.1. 38 Participants wore an emWave Pro sensor attached to their earlobe throughout the rest, stress, and recovery phases of the experimental task. The emWave Pro has been used in other research studies examining intervention outcomes.39–41 Measures of HRV are divided into time and frequency domains. Common frequency domain parameters include high-frequency (HF) band power (HF; ms 2 or normalized units), low-frequency (LF) band power (LF; ms 2 or normalized units), the ratio between HF and LF band powers (LF/HF), and very low-frequency (VLF) band power (VLF; ms 2 ). These have been included to assess common parasympathetic and sympathetic activity metrics related to stress induction.
Stress induction task
Stroop tasks are one type of cognitive task administered as a valid proxy of stress in several experimental settings.42–45 Between 5-min periods of rest and recovery HRV, participants completed an online Stroop task, requiring them to select the color of the word shown using keys corresponding to red, green, blue, and yellow. Each item response period was time-limited, and a red “X” would flash if a participant selected the wrong key in response to an item.
Data analysis
Psychophysiological data preparation
HRV data from rest, stress, and recovery phases were collected continuously to minimize loss of data due to starting and stopping of the emWave HRV monitor. Thus, recordings were between 15 and 24 min, including preparation, handling of technical issues with equipment and transitions between phases of the task. Trained research assistants documented the timestamp of the beginning and end of each phase (rest, stress, recovery) for each participant so that the HRV data file could be split into accurate 5-min segments that represented the same 5-min segments across participants. HRV data were detrended in Kubios 3.1 using a smoothness priors procedure. Frequency domain analyses utilized Welch's periodogram (Fast Fourier transformation) procedure. All analyses were conducted using SPSS v.26. 46
Baseline-to-post analyses
HRV intervals of 5-min segments were selected from rest, stress, and recovery phases at baseline and postgroup time points. Extracted frequency parameters were compared between pre- and post-intervention phases, using paired samples t-tests. Effect sizes (Cohen's d) were calculated and reported; significance was set at p < 0.05.
Associations between self-report and HRV
Change scores for self-report measures between T1 and T2 were calculated and correlated with T2 parameters of HRV that significantly changed across time. Assumptions of normality, linearity, multicollinearity, and homoscedasticity were examined. Significant correlates of HRV parameters were then entered as predictors into individual regression models using T2 HRV parameters as the outcome. Age, gender, change in mean heart rate from T1 to T2 recovery period, and the respective T1 HRV parameter were controlled for as per recommendations in the field. 47
Results
Study population
Descriptive demographic data are summarized in Table 1. Over half of participants (54.4%) identified with a minority racial/ethnic group and 41% of participants identifying as nonbinary and/or nonheterosexual. Study participants identified as members of a variety of religious groups, with the majority of participants not affiliating with any religious group (51.5%). Most participants (75%) reported elevation in symptoms of depression, anxiety, and/or PTS.
Baseline Sample Characteristics
Depression symptoms were measured using the Patient Health Questionnaire-9.
Anxiety symptoms were measured using the Generalized Anxiety Disorder-7.
Symptoms of PTS were measured using the PTSD Civilian Checklist.
PTS, posttraumatic stress.
Changes in physiological response to stress
Changes in frequency domains in the 5-min resting, stress, and recovery intervals from T1 to T2 are shown in Table 2. No significant changes were found in rest and stress HRV across time points. Across recovery phases, there were significant decreases in LF-HRV (n.u.), (p = 0.02), and LF/HF Ratio (p = 0.04) and increases in HF-HRV (n.u.), (p = 0.02).
Comparison of Heart Rate Variability at Pre-intervention (T1) and Post-intervention (T2)
Sample n = 68. Two-tailed paired samples t-tests were used to examine changes in frequency domain parameters in 5-min segments of a resting period at T1 and T2.
Very low-frequency HRV.
Low-frequency HRV in normalized units (n.u.).
High-frequency HRV in normalized units (n.u.)
HF, high-frequency; HRV, heart rate variability; LF, low-frequency; VLF, very low-frequency.
Relationships between changes in self-report and HRV
Associations between the HRV parameters at T2 recovery period and self-report variables indicated significance between LF-HRV, HF-HRV, and LF/HF ratio and emotion regulation, symptoms of PTS and Spiritual Decline. Results of the regression models (Table 3) indicated that there was a collective significant effect between changes in Spiritual Decline and LF/HF ratio at T2 in univariate models (p = 0.03) and near significance in the models using LF-HRV and HF-HRV as outcomes (LF-HRV: p = 0.05, HF-HRV: p = 0.05). The individual predictors were examined further and indicated that Spiritual Decline (LF-HRV: p = 0.02; HF-HRV: p = 0.02; LF/HF ratio: p < 0.01) was the only significant predictor in all three models.
Univariate Regression Analysis Summary for Change in Self-Report Variables Predicting T2 Heart Rate Variability
For each of the univariate models, the outcome measure is the respective HRV variable during the 5-min T2 recovery phase, and the primary predictor is the change in continuous variable from T1 to T2. Change in mean heartrate from T1 to T2 recovery, age, gender, and T1 HRV parameter is controlled. Bolded values indicate significance at p < 0.05 for individual predictor.
Changes in the total sum of the DERS were predictive of the T2 LF/HF ratio (p = 0.046). When examined further, the DERS was the only significant predictor in the respective univariate models (p = 0.03). None of the models with changes in PTS symptoms as a predictor were significant.
Discussion
The findings from this study evidence (1) improvements in HRV during recovery from stress following the delivery of the AA-A intervention, and (2) HRV outcomes were predicted by improvements in emotion regulation and, for the first time in the literature, reversal of Spiritual Decline. Null findings were reported across resting and stress reactivity periods. As noted in prior studies on this sample,29,30 participant demographics were representative of the larger population at the university with respect to racial and ethnic makeup. Gender and sexual minorities were overrepresented, which mirrors overrepresentation of members of these groups in rising rates of psychopathology among emerging-adult populations. 48
Changes in HRV across AA-A
The pattern of improvements observed within this sample across recovery periods (increased HF-HRV, decreased LF-HRV, and decreased LF/HF ratio) maps to changes observed within the frequency domain parameters across in vivo responses to prayer,49,50 and has been observed in nonexperimental studies of mind–body interventions.51,52 These changes, supporting Hypothesis 1, provide further evidence that parasympathetic dominance contributing to sympathovagal balance may reflect a biological substrate of spiritual well-being in the context of an acute stressor. These physiological findings may represent recovery from stress linked to spiritual recovery from negative life events.
Psychological and spiritual predictors of T2 HRV
Changes in self-reported psychological and spiritual well-being were associated with T2 HRV, supporting Hypothesis 2. In predictive models, decreases in difficulties with emotion regulation were associated with decreases in the LF/HF ratio, an index of sympathovagal balance. This relationship mirrors a longstanding theory that HRV is a physiological index of an individual's self-regulating capacity that assists with recovery from stress.12,53,54 As reversal of Spiritual Decline and DERS were significantly correlated (r = 0.51), research is warranted on the relationship between changes in spiritual well-being and shifts in self-regulation and perceptual processes such as emotion regulation and self-compassion.
There was evidence that improvements in Spiritual Decline were associated with lower LF-HRV and LF/HF ratio and higher HF-HRV. That the mean score on this measure at T1 indicated elevated levels of spiritual questioning and distress after negative life events and that 46% of the participants identify spirituality or religion as highly to moderately important suggest that many participants were grappling with a spiritual view of the world and spiritual identity that preexisted AA-A.
While there were no associations between HRV and the previously reported significant changes in spirituality and spiritual growth, 29 it is compelling that, within this sample, there was a process of spiritual recovery (i.e., improvement in spiritual struggle) which held promise for physiological improvements in the recovery from stress; this is the first such finding of this relationship and may be developmentally significant to the psychological and physiological sequelae from stress. It is reported that the magnitude of the protective effect of spirituality against the development of psychopathology is 50% greater among adolescents than the effect among adults. 55 Further, the risk for cardiovascular disease and related mortality is predicted by earlier stress reactivity and recovery,56,57 as evidenced by HRV. Thus, emerging adulthood may be a spiritual and physiological critical period, and part of this developmentally enhanced protective effect may be conferred via changes in physiological responses to stress.
Implications for IM
Interventions to improve HRV may offset the risk of mortality and morbidity associated with a stress-related illness.58,59 By supporting healthy spiritual development that mitigates the effects of stress, SMB wellness interventions may promote behaviors that underscore optimal physical and psychological functioning. This study, the first of its kind to show a link between spiritual recovery and improvements in HRV across an 8-week SMB wellness intervention among undergraduates, indicates that (1) Spiritual Decline may impact psychophysiological functioning among emerging adults, and (2) SMB wellness interventions may mitigate both spiritual and thereby physiological markers of recovery from stress. Thus, SMB wellness interventions may offer a spiritually and physiologically stressed subset of the population targeted to prevent long-term autonomic dysregulation via offsetting Spiritual Decline.
The association between Spiritual Decline and cardiovascular disease and functioning aligns with other research showing spiritual struggle to inform multiple domains of health included in holistic models, including IM. 27,36–39 Given the implications of Spiritual Decline, IM practitioners should assess spiritual functioning and utilize spiritually integrated interventions when appropriate to support healing across spiritual, psychological, and physical domains. Brief assessment of present and past spiritual beliefs has been shown to successfully screen for spiritual struggle or decline. 60 However, the use of these in IM as well as evidence-based spiritually integrated interventions are understudied, thus representing a gap in the IM literature that should be explored in future research,
Limitations
First, HRV monitors led to a greater percentage of data loss than would have been experienced by digital survey completion alone. Second, this sample is relatively small and does not allow more sophisticated modeling to examine the relationship among constructs. The stress induction task was only administered pre- and post-intervention, so the longer-term physiological implications are unknown. Finally, this study was an open trial and thus did not include a control comparison or randomization. Despite these limitations, these preliminary data provide proof of concept that across the delivery of an SMB wellness intervention among emerging adults, there exists an association between spiritual and psychophysiological recovery from stress.
Conclusions
Previous studies suggest that spiritual experience may induce a systemwide physiological process that promotes sympathovagal balance and manifests as enhanced awareness and interconnectedness with others, nature, and a Higher Power/Transcendent.24,25 In this study, we observed evidence of this relationship in the association between reversal or recovery from Spiritual Decline and psychophysiological recovery from stress. Notably, within this sample, improvements of a spiritual struggle, examined alongside common mechanisms of contemplative interventions, were connected with psychophysiological stress response and emotion regulation, a common mechanism of change in IM interventions. To our knowledge, these are the first data to identify changes in physiological recovery that occur hand-in-hand with recovery from spiritual injury across the delivery of a targeted preventative SMB wellness intervention.
These data are relevant in the context of the study of stress sequelae, including mental and medical illness. This line of inquiry deserves further investigation to fully understand the role of spiritual recovery in physiological resilience and recovery from stress and support the inclusion of SMB wellness interventions among other evidence-based interventions used in IM. To facilitate this, a multi-site study examining implementation of AA on college campus is underway.
Footnotes
Authors' Contributions
All persons who meet authorship criteria are listed as authors, and all authors certify that they have participated sufficiently in the work to take public responsibility for the content, including participation in the concept, design, analysis, writing, or revision of the manuscript. Conception and Design of the study: L.M., M.R.A., S.C.S. Acquisition of Data: M.R.A., S.C.S., E.J.M., A.C. Analysis and Interpretation of Data: M.R.A., S.C.S., L.M.. Drafting of Manuscript: M.R.A., S.C.S., L.M. Revising of Manuscript: M.R.A., S.C.S., L.M., E.J.M., A.C.
Disclaimer
Each author certifies that this material or similar material has not been and will not be submitted to or published in any other publication before its appearance in Integrative Medicine Reports.
Author Disclosure Statement
No competing financial interests exist.
Funding Information
This study was supported through funding from the Living Peace Foundation.
