Effects of Yoga on Psychological Stress and Autonomic Regulation in Adults: A Systematic Review of Mental Health and Physiological Outcomes

This is the authors' abstract. We don't add key points for this paper.

Yoga is a multidimensional mind body practice that includes physical postures, breathing techniques, and meditation or relaxation. There is evidence that yoga can affect aspects of psychological stress and physiological or autonomic regulatory processes. However, randomized trials have used different yoga interventions, enrolled diverse populations, and measured varied outcomes, limiting synthesis of the evidence. We undertook a systematic review of published randomized controlled trials of the effects of yoga on measures of psychological stress and physiological or autonomic regulatory processes in adults. Outcomes of interest included self-reported stress, anxiety, depression, emotional symptoms, heart rate variability, blood pressure, salivary cortisol, and salivary alpha-amylase. The included randomized controlled trials of yoga interventions comprised Hatha, Kundalini, Iyengar, and integrated styles as well as breathing and relaxation techniques. Across multiple trials, yoga interventions were associated with reductions in self-reported stress, anxiety, or depressive symptoms. Results for physiological outcomes were mixed, but heart rate variability analyses suggested potential autonomic regulatory effects. Trials of blood pressure yielded mixed but mostly beneficial results. In a recent trial of Hatha yoga, momentary self-reported stress was lower after intervention, but daytime salivary cortisol and alpha-amylase were not different across groups. Overall, the evidence suggests that yoga interventions can have beneficial effects on psychological stress and physiological regulatory systems. However, the findings are limited by inconsistencies across trials in interventions and outcomes. Larger trials examining standardized interventions and including multiple psychological, autonomic, and endocrine outcome measures are needed.