The Physiological Effects Of A Mindfulness-based Exercise Program On The Stress-levels Of College-age Females

A Mindfulness-Based Exercise Program (MBEP) includes techniques from the traditional Mindfulness-Based Stress Reduction (MBSR) program and incorporates exercise as a mindfulness technique. The goal of this intervention is to teach individuals how to cope with stressors since high stress levels are associated with disease. During acute stress, the autonomic and neuroendocrine systems play key roles in the stress response. Heart rate variability provides insight into the autonomic nervous system (ANS) and cardiac autonomic modulation. The cortisol response provides insight into the hypothalamic-pituitary-adrenal axis.

Purpose: To quantify the physiological stress response to a standardized stressor (Trier Social Stress Protocol [TSSP]) following an 8-week MBEP. The variables of interest were HRV and cortisol. Additionally, subjective stress measures were collected pre-post intervention to measure perceived stress.

Methods: Participants were matched for resting levels of cortisol and HRV and randomly assigned to an intervention group (MBEP) or a control (CTL) group. The MBEP group (n=10), ages 23±6, met 2 times a week for 1 hr each session for 8 weeks. The CTRL (n = 8) group, ages 26±5 yrs, did not participate in any formal training program. The testing protocol for the measurement of cortisol and HRV following the intervention was as follows: needle insertion and IV line established for 30 min; 20 min baseline; 20 min stressor; 20 min recovery 1; 20 min recovery 2; 20 min recovery 3. Two separate 2 × 5 repeated measures ANOVA's were used to analyze HRV and cortisol. Separate 2 × 2 repeated measures ANOVA's were used to analyze subjective levels of stress pre-post intervention.

Results: No significant differences were found between groups for HRV and cortisol; however trends were noted. Only the Spielberger's State Anxiety Inventory (SSAI) showed a significant difference in the pre- post-test score between groups (40±7 to 32±8 vs. 43±10 to 45±12, p=0.016).

Conclusion: A larger sample size is needed to increase the power of the test statistic in order to examine the trends that were noted in the biomarkers of stress. This study was supported by a grant from the University Medical Center Foundation and the Center for Women's Health and Gender Based Medicine, Texas Tech University Health Science Center.