Optimal yoga dose for improving cancer-related fatigue, quality of life, and sleep quality in breast cancer survivors: a Bayesian dose-response meta-analysis.

Background: During long-term treatment, breast cancer survivors (BCSs) often experience decreased sleep quality and quality of life and increased fatigue. The interplay between these factors continually worsens the physical and psychological states of BCSs. Although yoga exercise has been shown to improve these adverse outcomes, the exact dose required is unknown. The purpose of our study was to determine the optimal yoga dose for improving cancer-related fatigue, sleep quality, and quality of life in BCSs.

Methods: A systematic search of MEDLINE, Embase, the Cochrane Library, and Web of Science was conducted from the beginning of the database search until March 2024 to identify randomized controlled trials on the effects of yoga exercise on BCS-specific outcomes. Paired and dose-response meta-analyses were performed using Bayesian hierarchical random-effects models to analyze these effects.

Results: A total of 2423 breast cancer survivors were included in the 32 studies, with 1252 in the yoga intervention group and 1171 in the control group. Yoga intervention improved fatigue (standard mean difference [SMD]: - 0.55; 95% CrI, - 0.64 to - 0.45. Standard deviation [SD]: 0.32; 95% CrI, 0.23 to 0.45. RSRF ≤ 1.01), sleep quality (SMD: - 0.29; 95% CrI, - 0.43 to - 0.15. SD: 0.56; 95% CrI, 0.35 to 0.88. RSRF ≤ 1.01), and quality of life (SMD: 0.42; 95% CrI, 0.30 to - 0.53. SD: 0.32; 95% CrI, 0.23 to 0.45. RSRF ≤ 1.01) in BCS. It has a nonlinear dose-response relationship, a U-shaped dose-response relationship with fatigue and quality of life, and a positively correlated dose-response relationship with sleep quality. The optimal exercise dose for improving both fatigue and quality of life was 510 METs-min/week, and sleep quality significantly improved when the dose exceeded 160 METs-min/week. Yoga was less effective for fatigue during treatment compared to post-treatment, while its effects on quality of life and sleep quality remained relatively stable throughout both periods. Furthermore, with increasing age, the benefits of yoga interventions for improving fatigue and sleep quality in BCS decrease, while the benefits for improving quality of life increase.

Conclusions: This meta-analysis provided critical information on the optimal weekly dose of yoga exercise (220 min/week) to improve fatigue, sleep quality, and quality of life in patients with BCSs. Practitioners should consider the therapeutic stage and age of BCSs when developing yoga strategies to maximize the benefits.

Implications For Cancer Survivors: For BCS, personalized yoga interventions tailored to treatment stages and age, coupled with regular effectiveness assessments, can significantly enhance recovery and improve quality of life.