Dose-Response Meta-Analysis: At Least 150 Weekly Minutes of Aerobic Exercise Needed for Significant Waist and Fat Reduction

Background: Elevated body weight and adiposity remain major public health concerns worldwide, with overweight and obesity affecting nearly half of the adult population. Although various guidelines advocate for aerobic exercise as a core strategy in weight management, robust meta-analyses exploring dose-response relationships are scarce.

Objective: To clarify how different doses and intensities of supervised aerobic exercise affect body weight, waist circumference, and body fat in adults with overweight or obesity.

Methods: This systematic review and meta-analysis encompassed 116 randomized clinical trials (RCTs) including a total of 6880 participants (mean [SD] age, 46 [13] years). All studies involved supervised continuous aerobic interventions (e.g., walking or running) for at least 8 weeks. Comparisons were made against sedentary or usual-activity controls. Frequency, duration (minutes per week), and intensity (moderate, vigorous, or combined) of aerobic sessions were extracted.

Results: Across all trials, each additional 30 minutes per week of aerobic exercise was linked to a mean reduction of 0.52 kg in body weight (95% CI, −0.61 to −0.44), 0.56 cm in waist circumference, and 0.37 percentage points in body fat. Body weight and waist circumference showed largely linear decreases with increasing weekly exercise, whereas body fat percentage displayed a pattern suggesting that at least 150 minutes per week may be required to achieve clinically meaningful reductions (>2% reduction in body fat). Aerobic training was generally well tolerated, although a modest increase in mild musculoskeletal complaints was noted (risk difference, 2 more events per 100 participants).

Conclusions: Engaging in up to 300 minutes per week of aerobic exercise was associated with progressively greater benefits for weight control, waist circumference, and body fat. While even small doses yielded modest improvements, these findings suggest that an intensity of at least moderate level and a duration of at least 150 minutes per week may be necessary to achieve clinically important reductions in central obesity and fat percentage.

Implications for Practice: Clinicians managing patients with overweight or obesity can recommend a minimum of 150 minutes per week of moderate-to-vigorous aerobic training to achieve significant anthropometric changes. Gradual progression is essential to balance effectiveness and safety, especially in individuals with musculoskeletal constraints.

Study Strengths and Limitations: Strengths include the large number of RCTs, robust dose-response analyses, and consistent directions of effects. However, high heterogeneity, publication bias for certain fat measures, and limited data on medication use and health-related quality of life in longer trials were noted.

Future Research: Further trials should explore additional subgroup analyses (e.g., older adults, individuals with chronic comorbidities), longer durations of follow-up, and the integration of resistance training to optimize cardiometabolic outcomes.

Reference: Jayedi A, Soltani S, Emadi A, et al. Aerobic Exercise and Weight Loss in Adults: A Systematic Review and Dose-Response Meta-Analysis. JAMA Network Open. 2024;7(12):e2452185. DOI: http://doi.org/10.1001/jamanetworkopen.2024.52185