Effects of Mind–Body Exercises (Tai Chi/Yoga) on Heart Rate Variability Parameters and Perceived Stress: A Systematic Review with Meta-Analysis of Randomized Controlled Trials

Abstract

Background: Heart rate variability (HRV) as an accurate, noninvasive measure of the Autonomous Nervous System (ANS) can reflect mental health (e.g., stress, depression, or anxiety). Tai Chi and Yoga (Tai Chi/Yoga), as the most widely practiced mind–body exercises, have shown positive outcomes of mental health. To date, no systematic review regarding the long-lasting effects of Tai Chi/Yoga on HRV parameters and perceived stress has been conducted. Objective: To critically evaluate the existing literature on this topic. Methods: Five electronic databases (Web of Science, PubMed, Scopus, SportDiscus and Cochrane Library) were searched from the start of the research project to July 2018. Study selection, data extraction, and study quality assessment were independently carried out by two reviewers. The potentially identified randomized controlled trials (RCT) reported the useful quantitative data that were included only for meta-analysis. Results: meta-analysis of 17 medium-to-high quality RCTs showed significantly beneficial effects on HRV parameters (normalized low-frequency, Hedge’s g = −0.39, 95% CI −0.39 to −0.56, p < 0.001, I2 = 11.62%; normalized high-frequency, Hedge’s g = 0.37, 95% CI 0.22 to −0.52, p < 0.001, I2 = 0%; low-frequency to high-frequency ratio, Hedge’s g = −0.58, 95% CI −0.81 to −0.35, p < 0.001, I2 = 53.78%) and stress level (Hedge’s g = −0.80, 95% CI −1.17 to −0.44, p < 0.001, I2 = 68.54%). Conclusions: Stress reduction may be attributed to sympathetic-vagal balance modulated by mind–body exercises. Tai Chi/Yoga could be an alternative method for stress reduction for people who live under high stress or negative emotions.

Yoga and Cardiovascular Health Trial (YACHT): a UK-based randomised mechanistic study of a yoga intervention plus usual care versus usual care alone following an acute coronary event

“…Measures of HRV may be more sensitive to subtle changes than traditional tests of autonomic function, and improvements associated with yoga training or tai chi have been observed in systematic reviews for a number of parameters50 51; however, we found little evidence for any yoga-related benefits in these parameters over 3 months.…”

The Impact of Mind-Body Exercises on Motor Function, Depressive Symptoms, and Quality of Life in Parkinson’s Disease: A Systematic Review and Meta-Analysis

“…Mind-body exercise is a low-cost, easy-to-operate, low-impact, moderate-intensity aerobic exercise that emphasizes both skeletal muscle stretching and relaxation, physical coordination training, and emphasizes on breathing and movement control. The perfect combination of body and mind can have a positive effect on the body and mind, suitable for the rehabilitation of chronic diseases [14,15], especially for non-motor symptoms (depression, stress, pain, cardiovascular disease, and high blood pressure) [16][17][18]. At present, the common forms of physical and mental exercises mainly include Health Qigong, Tai chi, and Yoga.…”

Tai Chi Training Evokes Significant Changes in Brain White Matter Network in Older Women

“…Tai-Chi (TC) is a cognitive-motor exercise, which is commonly performed at mild-to-moderate exercise intensities [20,21]. Its choreographed routine typically consists of graceful, slow, fluid movements and it is performed in coordination with deep breathing, relaxation, and mental focus [22,23]. Such unique features have attracted people worldwide in pursuit of health and longevity, especially the frail elderly who experience functional decline [24,25].…”