Physical activity and its relationship to blood pressure in school children

The present report analyzes the relationship between physical activity and blood pressure in 1341 school children aged 7-14 years (girls = 598, boys = 743) participating in a screening for cardiovascular risk factors that took place in the suburban area of Naples. During the baseline examination, systolic (SBP) and diastolic (DBP) blood pressure, height, weight, and resting pulse rate (PR) were measured. The Harvard-Modified Step Test was also performed in order to score both a crude recovery index (RI) and an index corrected for the initial resting pulse rate (RI-PR) used as measures of the level of habitual physical activity. Significant differences have been found between the quartiles of distribution of both the crude recovery index and the corrected index in girls and boys with regard to systolic blood pressure but not diastolic. In both sexes, better responders to the Harvard-Modified Step Test showed on the average lower systolic blood pressure than poorer responders. In boys, the inverse association between systolic blood pressure and the recovery index was independent of the effect of age, body mass index, height, and resting pulse rate, while in girls the same association did not reach statistical significance. Our results support the hypothesis that systolic blood pressure is independently related to the level of habitual physical activity in children.