Aerobic Fitness, Fatness And Cardiovascular Disease Risk Factors Among Australian Youth

Abstract

Purpose The purpose of this study was to examine the combined influence of aerobic fitness and body fatness on cardiovascular disease (CVD) risk factors in youth. Methods The sample consisted of 860 boys and 755 girls aged 9–15 years who participated in the Australian Health and Fitness Survey. Participants were crosstabulated into four groups (low fat/fit; low fat/unfit; high fat/fit; high fat/unfit) using the lowest sex-specific quartiles of estimated percent body fat and maximal oxygen consumption to split the groups. ANCOVA, controlling for age, was used to examine group differences in CVD risk factors (blood pressures, triglycerides (TG), fasting total cholesterol (CHOL), high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), and TC:HDL-C). Results In males, significant differences across groups were observed for systolic blood pressure (SBP), mean arterial pressure (MAP), TG, HDL-C, LDL-C, and TC:HDL-C (p<0.05). In females, significant group differences were observed for SBP, diastolic blood pressure (DBP), MAP, and HDL-C (p<0.05). A trend for significance was evident for DBP in males (p=0.12) and for TG (p=0.13) and TC-HDL (p=0.057) in females. In females, blood pressure values were all significantly lower in the high fat/high fitness group compared to the high fat/low fitness group (p<0.02). For both genders, a general trend was also observed for lower blood pressure values in the low fat group (fit or unfit) compared to the high fat group (fit or unfit). This same trend was found for males in the blood lipid values. In females, there was a general trend for lower blood pressure and lipid values in the high fit groups (low fat and high fat) when compared to the low fit group (low fat and high fat). For both sexes, the high fat/low fitness group had a significantly higher composite CVD risk score (consisting of waist circumference, MAP, TG, and HDL-C) than the other groups. Conclusion The results provide evidence for the consideration of both fitness and fatness when interpreting CVD risk factors in youth. In females, there was some evidence of a protective effect of fitness over fatness but this was not evident in males.