Associations Between Change in Physical Activity Energy Expenditure, Aerobic Fitness and Body Fatness with Cardiovascular Disease Risk Factors

Abstract

Low levels of physical activity and aerobic fitness are consistently associated with an increased risk of cardiovascular disease (CVD). Numerous studies have also shown that obesity indicators (BMI, waist circumference, waist-to-hip ratio, and waist-to-height ratio) are associated with CVD risk factors. However, it is uncertain whether change in physical activity is associated with CVD risk factors and whether this association is independent of change in aerobic fitness and body fatness. PURPOSE: To examine the associations between change in physical activity energy expenditure (PAEE), aerobic fitness and body fatness with CVD risk factors. METHODS: In a population-based sample of 393 men (n = 176) and women followed prospectively for 5.6 years, we measured PAEE by individually calibrated heart rate monitoring, maximal aerobic fitness (VO2max estimated from a graded exercise test), waist circumference, total body fat (by bio impedance) and eight established CVD risk factors (total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, insulin, 2-h glucose, systolic and diastolic blood pressure) at baseline and follow-up. RESULTS: Change in PAEE was significantly and inversely associated with fasting triglycerides (B = −0.69; P = 0.028), insulin (B = − 1.14; P = 0.015) and 2-h glucose (B = −0.57; P = 0.027) at follow-up, after adjusting for sex, age, smoking status, baseline phenotype, aerobic fitness and body fatness (waist circumference or total body fat). These associations were materially unchanged after adjustment for change in aerobic fitness and body fatness (P <0.05). However, change in body fatness was consistently associated with change in all CVD risk factors, except for HDL-cholesterol, independently of change in PAEE and aerobic fitness (P <0.02). CONCLUSIONS: Change in physical activity level is inversely associated with insulin resistance, glucose intolerance and hyperlipidemia, independent of change in aerobic fitness and body fatness. This may have implications for cardiovascular risk reduction as increasing levels of physical activity may have protective effects without improvements in aerobic fitness, and reduced body fat mass. However body fatness was more strongly related to CVD risk factors than physical activity. Therefore, the combination of increasing levels of physical activity and avoidance of unhealthy weight gain is likely to be the most successful approach for the prevention of cardiovascular disease.