Optimal Tai Chi dose for improving anxiety, depression, and sleep quality in older adults: A Bayesian meta-analysis

Objective As the population ages, an increasing proportion of older adults experience mental health problems. Although Tai Chi ameliorates these negative outcomes, the required dosage remains unknown. This study aimed to determine the optimal dose of Tai Chi to improve anxiety, depressive symptoms, and sleep quality. Data sources A systematic search using MEDLINE, Embase, Cochrane Library, and Web of Science was conducted from the beginning of the respective database information until June 5, 2025. Review methods A pairwise and dose-response meta-analysis using Bayesian hierarchical random-effects models to analyse the effects of a Tai Chi intervention on anxiety, depression, and sleep quality in older adults. In addition, the quality of the literature was assessed using the Cochrane Risk of Bias Tool 2. Results A total of 2843 older adults were enrolled in 37 randomised controlled trials, including 1424 (50.1%) in the Tai Chi group. Tai Chi intervention improved anxiety (standardized mean difference (SMD) : −0.47, 95% credible interval (CrI): −0.65 to −0.30), depressive symptoms (SMD: −0.41, 95% CrI: −0.50 to −0.33). However, while Tai Chi improved sleep quality in older adults, the effect, though statistically significant, was small in magnitude (SMD: −0.12, 95% CrI: −0.20 to −0.04), with large heterogeneity. Conclusion Tai Chi is an effective intervention for improving mental health and sleep in older adults, with dose-dependent benefits. Our findings establish an optimal therapeutic target of 500-700 MET-minutes/week, transforming Tai Chi from a general recommendation into a specific, evidence-based prescription for clinical practice.