Effects of yoga on heart rate variability and mood in women: A randomized controlled trial

Objective: To examine the effects of an 8-week yoga program on heart rate variability and mood in generally healthy women. Design: Randomized controlled trial. Participants: Fifty-two healthy women were randomly assigned to a yoga group or a control group. Interventions: Participants in the yoga group completed an 8-week yoga program, which comprised a 60-minute session twice a week. Each session consisted of breathing exercises, yoga pose practice, and supine meditation/relaxation. The control group was instructed not to engage in any yoga practice and to maintain their usual level of physical activity during the study. Outcome measures: Participants' heart rate variability, perceived stress, depressive symptoms, and state and trait anxiety were assessed at baseline (week 0) and after the intervention (week 9). Results: No measures of heart rate variability changed significantly in either the yoga or control group after intervention. State anxiety was reduced significantly in the yoga group but not in the control group. No significant changes were noted in perceived stress, depression, or trait anxiety in either group. Conclusions: An 8-week yoga program was not sufficient to improve heart rate variability. However, such a program appears to be effective in reducing state anxiety in generally healthy women. Future research should involve longer periods of yoga training, include heart rate variability measures both at rest and during yoga practice, and enroll women with higher levels of stress and trait anxiety.