Less sitting, more physical activity and higher cardiorespiratory fitness: associations with weight status among a national sample of children

Background: Very few studies have evaluated the independent and combined associations of sedentary behavior (SB), moderate-to-vigorous physical activity (MVPA) and cardiorespiratory fitness (CRF) on obesity. Our recent work has evaluated this paradigm in the adult population,but no study has evaluated this paradigm in the child population, which was the purpose of this study. Methods: A national sample of children (N=680, 6-11 years) were evaluated via the National Youth Fitness Survey; this study was conducted in 2012, employing a nationally representative sample, occurring across 15 different geographic regions in the United States. SB and MVPA were assessed via parental recall, with CRF objectively measured via a treadmill-based aerobic test. Obesity was determined for measured body mass index. A PACS (Physical Activity Cardiorespiratory Sedentary) score was created ranging from 0-3, indicating each child’s number of positive characteristics (PA, CRF, SB). Results: Meeting MVPA guidelines (OR adjusted=0.47; 95% CI: 0.29-0.77) and above-median CRF (OR adjusted=0.12; 95% CI: 0.07-0.21), but not SB (OR adjusted=0.62; 95% CI: 0.35-1.10),were associated with reduced odds of obesity. Compared to those with a PACS score of 0, the odds of obesity for PACS scores of 1-3, respectively, were: 0.31 (0.18-0.53), 0.12 (0.04-0.34),and 0.05 (0.02-0.10). Conclusion: These findings highlight the need for public health strategies to promote child MVPA and CRF, and to reduce SB.