Optimal exercise modalities and dose selection to reduce leptin levels in overweight or obese individuals: a network meta-analysis and dose–response relationship study

Individuals who are overweight or obese often exhibit elevated leptin levels. Previous studies have indicated that exercise interventions can reduce leptin concentrations; however, the comparative effectiveness of different exercise modalities and their dose–response relationships remains unclear. This study aimed to evaluate the effects of various exercise interventions on leptin levels and identify the optimal exercise dose. This study employed a network meta-analysis and dose–response modeling to systematically assess the impact of different exercise modalities and doses on leptin levels in overweight or obese populations, with the goal of identifying optimal intervention strategies. A systematic search was conducted in PubMed, Web of Science, Embase, Cochrane Library, and EBSCO databases to identify randomized controlled trials (RCTs) with an intervention duration of at least 4 weeks. Included exercise modalities were aerobic exercise (AE), resistance training (RT), combined training (COM), and high-intensity interval training (HIIT). Network meta-analysis and dose–response analysis were performed using Stata 16.0 and R software. A total of 54 RCTs involving 2,786 participants were included. The network meta-analysis revealed that, compared with the control group (CON), RT (SMD = -1.23, 95% CI: -1.77 to -0.69), AE (SMD = -0.85, 95% CI: -1.24 to -0.45), and COM (SMD = -0.82, 95% CI: -1.32 to -0.33) significantly reduced leptin levels, whereas the effect of HIIT (SMD = -0.51, 95% CI: -1.16 to 0.14) was not statistically significant. According to the SUCRA rankings, RT (92.9%) was the most effective intervention, followed by AE (61.4%) and COM (60.0%), with HIIT (33.9%) being the least effective. A U-shaped dose–response relationship was observed between exercise dose and leptin levels. The minimum effective dose was 490 MET-min/week, while the optimal dose was 1,200 MET-min/week (SMD = -0.91; 95% CrI: -1.45 to -0.37). Beyond 1,470 MET-min/week, the effect declined and became non-significant. This study demonstrated that exercise interventions can effectively reduce leptin levels in overweight or obese individuals. AE, RT, and COM appear to be effective modalities for improving leptin regulation. A nonlinear dose–response relationship was observed between total exercise volume and leptin levels, with the minimum effective dose estimated at 490 MET-min/week. Notably, RT yielded significant effects at lower doses (320 MET-min/week), suggesting its high efficiency and practical value. CRD420251003242.