Obesity And Unhealthy Cardiorespiratory Fitness In A Cohort Of Children And Adolescents

Pediatric obesity is increasing worldwide, whereas cardiorespiratory fitness (CRF) seems to be declining. It is suggested that the combination of excessive body weight and low cardiorespiratory fitness increases the risk of health abnormalities, with most evidence presented in adults. Little information exists in youth on the coexistence of this unhealthy profile (i.e., high body weight and low CRF). PURPOSE: To examine 1) the coexistence of obesity and low CRF, at the level to be considered unhealthy, and 2) the stability (tracking) of this profile in a cohort of boys. METHODS: 1754 European boys, aged 8- to 14-years old, were tested for CRF using the 20-m shuttle run test. Based on international cut points that correspond to a VO2max of 41.8 ml/kg/min they were classified as having healthy (H) or unhealthy (UN) CRF. Age-specific BMI cut points were used to classify normal (N) and overweight and obese (OO) groups. Chi-square was performed with four groups (i.e. N/H, N/UN, OO/H, and OO/UN) and the odds ratios were calculated. 353 of those boys were followed for an average of 3.79 ± 0.83 years (range: 2.97-6.06 years). RESULTS: The odds that a boy was OO/UN compared to the normal body weight category ranged from 2.67 (13-years old) to 6.74 (9-years old). The odds of being fat but fit was 0.32. Nearly 57% (56.6%) of the participants remained in the same category, whereas 28.0% of them had at least one category changing to worst (Cohen’s Kappa = 0.557, p < 0.001; substantial agreement). CONCLUSIONS: Assuming the CRF cut points apply to all samples, the risk of boys with an unhealthy profile of combined excessive body weight and low cardiorespiratory fitness seems relatively high. Additionally, the stability of this unhealthy profile was substantial. These findings support the call for actions that prevent body weight increase and promote physical activity and fitness improvement in children and adolescents.