Examining the utility of thresholds for aerobic fitness related to resting blood pressure and BMI in Portuguese children.

Objectives: This study examined the utility of the Ruiz et al. cut-points when examining body mass index (BMI) and resting blood pressure in young people.

Methods: Two hundred fifty-six children (154 girls and 102 boys) aged 7-16 years underwent assessment of BMI, physical maturation, resting systolic blood pressure (SBP) and diastolic blood pressure (DBP) and cardiorespiratory fitness using breath by breath gas analysis during treadmill testing to exhaustion.

Results: Results from a series of 2 (fit vs. unfit) × 2 (gender) ways analysis of covariance, controlling for maturation indicated higher SBP in the unfit group compared to the fit group (P = 0.001), higher DBP in the unfit group compared to the fit group (P = 0.04) and higher BMI (in unfit) than fit children (P = 0.0001). Males had significantly higher BMI than females (P = 0.04). Maturation as a covariate was significantly and positively associated with SBP (P = 0.003), DBP (P = 0.004), and BMI (P = 0.001).

Conclusions: This study suggests that the Ruiz et al. cut-points are valid in distinguishing between children with higher and lower BMI and resting BP values.