Abstract
Physical Activity (PA) guideline recommendations for young people are intended to increase fitness and prevent overweight and obesity. However, little is known about the heterogeneity in health-related outcomes experienced by guideline concordant children.
PURPOSE: To prospectively investigate the associations between PA intensity and unfavorable health trajectories among physically active children aged between 6 and 12 yrs.
METHODS: This prospective study (2.5 yrs) included 391 students (8.1 ± 1.4 yrs) from ten public schools participating in the Childhood Health, Activity, and Motor Performance School Study Denmark (CHAMPS-dk). All children performed a daily minimum of 60-min of moderate-to-vigorous physical activity (MVPA), measured by accelerometers, at baseline and 30 months. Trajectories of body mass index (BMI), waist circumference, and aerobic fitness were constructed with a group-based multi-trajectory model and associations between PA measures and health trajectories were modeled with logistic regression.
RESULTS: Overall, 9.1% of guideline-concordant children were classified as members of an unfavorable health trajectory with BMI and waist circumference indicating overweight/obesity, and lower aerobic fitness. Time in sedentary [OR 0.98 95%CI (0.94-1.02)] and moderate intensity activity were not associated with membership in an unfavorable health trajectory [OR 0.86 95%CI (0.71-1.04)]. Each 5-min in MVPA was associated with a 23% reduction [OR 0.77 95%CI (0.66-0.91)] in the odds of being in the unfavorable health trajectory group. For every 5-min spent in vigorous PA, there was a 39% reduction in the odds of being classified as a member of the unfavorable health trajectory [OR 0.61 95%CI (0.46-0.80)].
CONCLUSION: Additional 5-min in MVPA and vigorous PA are associated with better health-related outcomes among children who adhere to PA guideline recommendations. Vigorous PA was the strongest predictor of health outcomes. PA guidelines should place greater emphasis on vigorous intensity PA.