Cardiorespiratory Fitness, Physical Activity Patterns and Coronary Risk Factors in Preadolescent Boys

Abstract

The relationships between cardiorespiratory fitness, daily physical activity, and selected coronary artery disease (CAD) risk factors were evaluated in a sample of 91 preadolescent boys. Cardiorespiratory fitness was assessed by direct measurement of maximal oxygen uptake (V̇O₂max). Physical activity level was assessed using daytime heart rate telemetry. CAD risk factors included total cholesterol, fasting triglycerides, HDL-cholesterol, LDL-cholesterol, fasting blood glucose, systolic and diastolic blood pressures, and body fat content. The mean value of V̇O₂max exhibited significant negative relationship with body fat percent (r = -0.55). Controlling the effects of age, body mass index and body fat percent resulted in a significant inverse relationship between physical activity and systolic (r = -0.29) and diastolic (r = -0.28) blood pressures. Analysis of data by quartiles revealed significant differences only in body fat percent across fitness categories, while no significant differences were detected in the other CAD risk factors. However, higher HDL-cholesterol and lower triglycerides levels were observed in those boys with higher levels of physical activity. It was concluded that except with body fatness, cardiorespiratory fitness is not strongly associated with lower CAD risk factors, while physical activity level was significantly associated with lower blood pressure level but not with the other CAD risk factors.

Key words

Cardiorespiratory Fitness - Coronary Artery Disease - Exercise - Preadolescent Boys - Risk Factors