The impact of long-term exercise on liver function, fatty liver progression, and related metabolic markers in NAFLD patients: a meta-analysis of randomized controlled trials

Background Evidence on the effects of long-term exercise on liver function, fatty liver progression, and metabolic markers in non-alcoholic fatty liver disease (NAFLD) patients is limited. Objective This study aimed to assess, through a meta-analysis, the impact of long-term exercise on liver function, fatty liver progression, and related metabolic indicators in NAFLD. Methods The study investigated 5 databases and included 18 studies published up to September 2025. A random-effects model was used, with subgroup and regression analyses to explore intervention effects. Results Long-term exercise significantly reduced alanine aminotransferase (ALT; standardized mean differences, SMD = −0.78, 95% CI: −1.15 to −0.40), aspartate aminotransferase (AST; SMD = −0.65, 95% CI: −1.07 to −0.23), and liver fat content (SMD = −0.68, 95% CI: −0.98 to −0.38). Additionally, significant improvements were observed in body weight, body mass index (BMI), visceral adipose tissue (VAT), and homeostasis model assessment of insulin resistance (HOMA-IR). No significant changes in liver stiffness and glycated hemoglobin percentage (HbA1c%) were observed, which may be due to the limited number of studies on liver stiffness (only three studies were included). Subgroup analyses identified exercise type, gender, and region as moderators of the intervention effects. Regression analysis showed that BMI was significantly correlated with age ( p = 0.02), while no other variables showed significant correlations. Conclusion Long-term exercise significantly improves liver enzymes (ALT and AST) and fat content in NAFLD patients, together with BMI, VAT, and HOMA-IR, but has no significant effects on liver stiffness and HbA1c%. Nevertheless, the statistical power of this meta-analysis is limited due to the small sample sizes of the included studies and the restricted number of studies available for certain outcomes, with liver stiffness evaluated in only four studies. Systematic review registration https://www.crd.york.ac.uk/ , Identifier CRD420251163167.