Effects of exercise on cardiorespiratory fitness in children and adolescents with overweight and obesity: a systematic review and meta-analysis of 72 randomized controlled trials.

OBJECTIVE: Evaluate the impact of exercise on the cardiorespiratory fitness of the children and adolescents with overweight or obesity, and explore possible influencing factors. STUDY DESIGN: This meta-analysis adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and included randomized controlled trials (RCTs) published between January 2005 and January 2025. Data were retrieved from PubMed, Embase, Cochrane Library, CNKI, WanFang, and other databases. The included studies evaluated the effects of exercise on six cardiorespiratory fitness (CRF) indicators. RESULTS: A total of 72 eligible RCTs with 5,320 children and adolescents with overweight or obesity were included (The mean age and BMI of participants were 12.93 ± 2.47 years and 28.08 ± 4.74 kg/m², respectively). Compared to the control group, exercise was associated with improvements in Body Mass Index(MD:-1.14[-1.57,-0.71] kg/m2, P < 0.00001), maximal oxygen uptake(MD:2.43[1.51,3.34] ml kg⁻¹ min⁻¹, P < 0.00001), peak oxygen uptake(MD:2.06[1.12,2.99] ml kg⁻¹ min⁻¹, P < 0.00001), systolic blood pressure(MD:-3.16[-5.00,-1.31] mmHg, P < 0.00001), diastolic blood pressure(MD:-1.38[-2.13,-0.63] mmHg, P = 0.0003), and resting heart rate(MD: -3.23[-4.70,-1.76] bpm, P < 0.0001). CONCLUSION AND RELEVATION: This study demonstrates that exercise is an effective tool for improving low CRF caused by overweight and obesity in children and adolescents. Exercise programs with a duration of ≤ 12 weeks, a frequency of ≥ 3 sessions per week, and a session length of ≤ 60 min were associated with greater improvements in CRF. Combined exercise or moderate-to-high-intensity interval training can achieve superior improvements compared with conventional exercise programs. In addition, stricter supervision plans are necessary during exercise.