Fedewa MV, et al. - Researchers examined the impact of exercise interventions lasting ≥ 2 weeks on leptin levels. They analyzed data from studies wherein human participants were randomized to an exercise training group or non-exercise comparison group for an exercise training intervention. All studies included were peer-reviewed and published in English. They used random-effects models to aggregate a mean effect size (ES) and 95% confidence intervals (CIs), and to determine potential moderators. Overall, the analysis of 72 randomized controlled trials revealed evidence demonstrating an association of engaging in chronic exercise training (≥ 2 weeks) with a decrease in leptin levels for individuals regardless of age and sex. However, a greater decrease in leptin was noted with a decreased percentage of body fat.