Resistance training for postmenopausal women: systematic review and meta-analysis

IMPORTANCE: Numerous studies have been published assessing the effects of resistance muscle training to mitigate menopausal symptoms, given the endocrine muscle function and its metabolic regulation. Therefore, mapping and synthesizing high-quality studies are necessary to help clinical decisions. OBJECTIVE: The aim of this study was to assess the effects (benefits and harms) of resistance muscle training for postmenopausal women. EVIDENCE REVIEW: Electronic searches were conducted in MEDLINE (via PubMed), EMBASE, CENTRAL, PEDro, LILACS, and SPORTDiscus up to December 2021. Two independent reviewers selected the retrieved references and extracted relevant data from included studies. The methodological quality (risk of bias) using the Cochrane Risk of Bias table and the certainty of the evidence (GRADE approach) were assessed. FINDINGS: Twelve randomized clinical trials (n = 452) with unclear to high risk of bias were identified. Compared with no exercise, resistance training (up to 16 weeks) seems to promote an improvement in functional capacity (mean difference [MD], 2.90 points; 95% CI, 0.60-5.20) and bone mineral density (MD, 0.10; 95% CI, 0.10-0.10) and a reduction in the hot flash frequency (13/29 vs 1/29; risk ratio, 13.0; 95% CI, 1.82-93.01) and fat mass (MD, -3.15; 95% CI, -6.68 to 0.38), and no differences were observed between groups regarding abdominal circumference and body mass index. When compared with aerobic exercises, resistance training may result in a reduction of hot flash frequency (7/18 vs 14/18; risk ratio, 0.50; 95% CI, 0.27-0.94) and fat mass (MD, -7.80; 95% CI, -14.02 to -1.58) and no difference in the quality of life and body mass index. Regarding safety, no serious adverse events were reported. Based on the GRADE approach, the certainty of this evidence was graded as very low to low, leading to imprecisely estimated effects. CONCLUSIONS AND RELEVANCE: Resistance muscle training seems to improve postmenopausal symptoms and functional capacity. Given the low to very low certainty of the evidence, further randomized clinical trials with higher methodological quality and better reports are still needed. As an implication for clinical practice, health professionals should consider individualized aspects such as the previous history of exercise practice, physical capacity, and adaptation period.