Objective: 1) To examine whether cardiorespiratory fitness (CRF) is associated with waist circumference (WC) and overall and abdominal fatness in eight-year-old girls and boys. 2) To determine whether children with high CRF have lower WC, overall and abdominal fatness within the same body mass index (BMI) category compared with those with low CRF.
Design: A cross-sectional study of 304 eight-year-old children in Tampere, Finland whose parents responded to a postal invitation and participated in measurements.
Measurements: Total body fat percentage (BF%), abdominal region fat percentage (AF%), and fat-free mass (FFM) were assessed by dual-energy X-ray absorptiometry (DXA). WC, height and weight were measured. International BMI sex- and age-specific cut-off points were used for overweight and obesity definition, and participants were divided into two categories: normal weight or overweight/obese. CRF was assessed with a maximal multistage 20-m shuttle run test (20-mSRT).
Results: Of the children, 81% were normal weight and 19% were overweight/obese. CRF was inversely associated with WC (p<0.011), BF% (p<0.001) and AF% (p<0.001) independent of age, sex and BMI. Within the same BMI category, children with high CRF had significantly lower WC (p=0.001), BF% (p<0.001) and AF% (p<0.001) compared with children with low CRF.
Conclusion: Eight-year-old children with high CRF had lower overall and abdominal fatness compared with children with low CRF, independent of age, sex and BMI. CRF should be an important target already at a young age in preventing overall and abdominal obesity.