Dose-response Relationship between Exercise and Cardiovascular Disease Risk Factors

Abstract

PURPOSE: Although exercise has been shown to be effective for improving cardiovascular disease (CVD) risk factors, dose-relationship between exercise and CVD risk factors has not been clear. The aim of the present study was to assess the dose-response relationship based on the data of participants of the Sapporo Fitness Club Trial (SFCT). METHODS: The data of the exercise intervention group (M/F = 107/142, Age 67.6±6.4 yr, BMI 26.4±2.0) of SFCT were analyzed. The participants were obese or overweight, and had an additional 2 or 3 CVD risk factors (i.e., hypertension, hyper lip idemia, or hyperglycemia). The exercise program consisted mainly of a mo derate-intensity bicycle exercise with light resistance exercise and stretching for 6 months. Energy expenditure (EE) during stationary bicycle exercise per week was calculated from monitored HR. Based on quartiles of EE, the participants were classified into 4 groups. Pearson correlation analysis and analysis of covariance (ANCOVA) with a baseline value of a risk factor as a covariate were used for statistical analysis. RESULTS: The mean EE of the 1st, 2nd, 3rd, and 4th quartile group were 56.7, 142.0, 219.3, and 587.4 kcal/wk, respectively. Table 1 shows baseline characteristics and changes from baseline after 6 months of exercise. The greater EE was associated with the greater decreases in BMI (r=−0.271, p < 0.01), waist circumference (r=−0.190, p < 0.01). Among other CVD risk factors, only LDL-C correlated weakly with EE (r=−0.154, p < 0.05). However, in blood pressure, lipid profiles other than LDL-C, blood glucose and hemoglobin A1 c, relationships with EE were not significant. The ANCOVA did not discern a J-curve effect or any other significant non-linear relations.Table 1: Mean Baseline Characteristics and Changes from Baseline Values (δ)CONCLUSIONS: Exercise energy expenditure showed a linear dose-response relationship with decreases in the body weight and waist circumference. In contrast, it did not correlate with changes in most CVD risk factors. Factors other than exercise may play a larger role in altering them.