The effect of physical activity on health outcomes in individuals with anorexia nervosa: a systematic review and meta-analysis study

This meta-analysis systematically evaluates the effect of physical activity on specific health outcomes in individuals with anorexia nervosa (AN), including body composition parameters and quality of life, to inform clinical exercise rehabilitation. This systematic review and meta-analysis was conducted in accordance with PRISMA guidelines. A comprehensive search of PubMed, EMBASE, Web of Science, the Cochrane Library, and CINAHL was performed from database inception to March 2024. Eligible studies were randomized controlled trials that compared physical activity interventions plus usual care against usual care alone in individuals with anorexia nervosa. Two independent reviewers screened articles, extracted data, and assessed risk of bias. Random-effects models were used for all meta-analyses. Eleven RCTs met inclusion criteria, with all 11 contributing data to meta-analysis. Pooled analyses showed no statistically significant differences in body weight (MD = 0.62, 95% CI [-0.74, 1.98], P = 0.37), BMI (MD = 0.59, 95% CI [-0.42, 1.60], P = 0.25), body fat percentage (MD = 0.62, 95% CI [-0.22, 1.46], P = 0.15), or quality of life (SMD = 0.07, 95% CI [-0.53, 0.68], P = 0.82), whereas muscle strength improved significantly (SMD = 0.99, 95% CI [0.45, 1.53], P < 0.001). Physical activity interventions were well tolerated, with no adverse effects on weight restoration. Sensitivity analyses excluding high-risk studies confirmed robustness, and no meaningful publication bias was detected. Supervised physical activity, particularly resistance training, shows promise as a safe adjunct to standard care in anorexia nervosa. Pooled results indicate significant gains in muscle strength, whereas no statistically significant between-group differences were detected for body weight, BMI, body fat percentage, or quality of life. Due to the limitations of the available data, future studies should include larger multicenter trials, standardized protocols, and longer follow-up periods, with greater attention to outcomes such as eating disorder psychopathology, compulsive exercise behaviors, and relapse rates to support the development of individualized exercise prescriptions. Not applicable. Level I: Evidence obtained from systematic reviews and meta-analyses. Supervised exercise training, particularly resistance training, can be safely incorporated into the clinical management of anorexia nervosa without compromising weight restoration. This meta-analysis provides quantitative evidence that appropriately prescribed physical activity significantly improves muscle strength in individuals with anorexia nervosa. Exercise prescriptions for patients with anorexia nervosa should be individualized, initiated at low intensity, and progressed gradually under multidisciplinary supervision.