Physical fitness, physical activity, and fatness in relation to blood pressure and lipids in preadolescent children. Results from the FRESH Study.

PURPOSE: The cross-sectional gender patterns of fitness, activity, and fatness were examined in relation to blood pressure and lipids in 9- to 10-year-old children.
METHODS: Subjects were fourth graders (26 boys and 27 girls) participating in FRESH, a school-based heart health program. The main variables of interest were fitness determined on a treadmill, habitual physical activity by self-report, fatness by skinfolds and body mass index, blood pressure, and lipoprotein lipids.
RESULTS: Physical fitness and activity were higher in boys, whereas fatness and triglycerides were higher in girls. Systolic blood pressure correlated positively with fatness in girls, and there was a trend for this relationship in boys. In boys, total LDL cholesterol correlated positively with fatness and negatively with fitness. By multivariate analysis, fitness was the primary correlate of total and LDL cholesterol. In girls, fitness correlated positively with total and LDL cholesterol. This finding was opposite in boys. Fatness correlated negatively with HDL cholesterol in boys.
CONCLUSION: Boys are more fit and active and less fat than girls. Fatness in young children already shows a relationship with heart disease risk factors. In boys, fitness shows a favorable relation to lipids. These data along with other studies suggest that more consistent relationships among fitness, activity, fatness, blood pressure, and lipids are likely to emerge as children approach adolescence. The findings also underscore the complexity of defining these relationships in young children.