Exercise training improves hepatic enzymes, body mass index, and cardiorespiratory fitness in adults with metabolic dysfunction-associated steatotic liver disease: a systematic review and meta-analysis

Background: Exercise is recommended for metabolic dysfunction-associated steatotic liver disease (MASLD). Recent reviews have addressed specific exercise modalities or selected outcome domains, but an updated integrated appraisal of hepatic, metabolic, and cardiorespiratory responses across randomized trials remains needed. Method: We conducted a PRISMA 2020-compliant systematic review and meta-analysis of randomized controlled trials in adults with MASLD or legacy diagnoses of non-alcoholic fatty liver disease/non-alcoholic steatohepatitis. PubMed, Embase, CENTRAL, Scopus, Web of Science, and SPORTDiscus were searched from inception to June 2026. Post-intervention mean differences (MDs) or standardized mean differences (SMDs) with 95% confidence intervals (CIs) were pooled. Risk of bias was assessed using RoB 2 and certainty using GRADE. Results: max (MD 4.08 mL/kg/min, 95% CI 1.00 to 7.16). Pooled effects for liver fat/steatosis, HOMA-IR, and HbA1c were not statistically significant. Egger testing showed no significant asymmetry for ALT or AST, whereas BMI showed funnel-plot asymmetry consistent with possible small-study effects. Conclusion: Exercise training improves hepatic enzymes, BMI, and cardiorespiratory fitness in adults with MASLD/NAFLD, whereas evidence for liver fat and glycemic outcomes remains less certain. PROSPERO: CRD420261416397. Systematic review registration: https://www.crd.york.ac.uk/PROSPERO/, identifier CRD420261416397.