Effect of an office worksite-based yoga program on heart rate variability : a randomized controlled trial

![CDATA[Chronic work-related stress is an independent risk factor for cardiometabolic diseases and associated mortality, particularly when compounded by a sedentary work environment. PURPOSE: To determine if an office worksite-based yoga program could improve physiological stress, evaluated via heart rate variability (HRV), and physical and psychological health outcomes. METHODS: Thirty-seven healthy adults employed in university-based office positions were randomized upon the completion of baseline testing to an experimental or control group. The experimental group completed a 10-week yoga program, prescribed three sessions per week during lunch hour (50 min per session). An experienced instructor led the sessions, which involved asanas (postures), vinyasa (exercises), pranayama (breathing exercise) and meditation. The primary outcome was the high frequency (HF) power component of HRV. Secondary outcomes included additional HRV parameters (i.e. low frequency (LF) and total power, and LF:HF), musculoskeletal fitness (i.e. push-up, side-bridge, and sit & reach tests) and psychological indices (i.e state and trait anxiety, quality of life and job satisfaction). RESULTS: Thirty-four participants, 17 per group, completed the study and were included in per protocol analyses. Measures of HRV all failed to change in the experimental group versus the control group, except that the experimental group significantly increased LF:HF versus control (p=0.04), contrary to our hypothesis. Flexibility, evaluated via sit & reach test increased in the experimental group versus the control group (p<0.001). No other adaptations were noted. Post hoc analysis comparing participants who completed ≥70% of yoga sessions (n=11) to control (n=17) yielded the same findings, except that the high adherers also reduced state anxiety (p=0.04) and tended to reduce HF power (p=0.07) and increase push ups (p=0.11). CONCLUSIONS: A 10-week yoga intervention delivered at the office worksite during lunch hour did not improve HF power or other HRV parameters. However, improvements in flexibility, state anxiety and musculoskeletal fitness were noted with high adherence. Future investigations should involve more frequent and longer durations of yoga training, and cohorts who suffer from high work-related stress.]]