0401 Effects of a 4-week Vinyasa Yoga Intervention on Sleep and Cardiovascular Health in Adults with Insomnia Symptoms

Abstract Introduction Insomnia is associated with an increased risk for cardiovascular disease. Yoga may have the potential to improve both sleep and cardiovascular health. However, there is limited evidence of how vinyasa yoga (VY), a form of yoga that links breath with movement and exhibits a greater energy expenditure than most other styles, impacts sleep and cardiovascular function. The purpose was to examine the effects of a 4-week VY intervention on sleep and cardiovascular health in adults with insomnia symptoms. Methods 33 insufficiently active adults (84.8% female; 78.8% White; age=34.9±10.6 y; body mass index=28.9 kg/m2) with at least mild insomnia symptoms (Insomnia Severity Index [ISI]≥10) were randomized to a 4-week VY intervention (n=17) or non-active control (CON; n=16). VY practiced 3x/week following pre-recorded 60-minute videos and CON maintained their current lifestyle. Resting daytime measures of blood pressure, heart rate (HR) and heart rate variability (HRV) were obtained at baseline and post-intervention. Sleep was measured using the ISI, 7 nights of actigraphy, and a sleep diary. On one night during the sleep assessment, participants wore a chest HR monitor overnight to assess HRV. HRV was standardized for sleep duration, with root mean square of successive differences (RMSSD) the primary HRV outcome. Analyses compared changes in daytime cardiovascular health, sleep, and nocturnal HRV from pre- to post-intervention between groups using linear mixed models and Cohen’s d effect sizes. Results The change in ISI score from baseline to post-intervention did not differ between VY (15.18±0.96 to 9.93±1.00) and CON (16.63±0.98 to 13.87±0.98) (p=0.11) despite a medium-sized between-group effect size (d=-0.70) favoring VY. Among highly adherent participants, VY reduced ISI scores to a greater extent than CON (p=0.002). Changes in nocturnal RMSSD HRV and daytime resting cardiovascular measures were not statistically significant between groups (each p≥0.30). However, daytime resting HR decreased for VY (72.41±2.92 to 69.50±2.60 bpm) and increased for CON (70.47±2.54 to 72.93±2.60 bpm) (p=0.047). Conclusion Insomnia symptom reductions may be most apparent among those who consistently practice VY. VY had minimal impact on acute indications of cardiovascular health, suggesting changes may not occur with an intervention that is relatively short duration and/or low frequency. Support (if any)