Effects On Cardiovascular Risk Factors Of Three 48-week Community-based Exercise Interventions

Abstract

A sedentary lifestyle is associated with cardiovascular disease (CVD). Blood pressure (BP) and blood lipids (cholesterols) are key mediators of CVD. A substantial body of evidence demonstrates reduced CVD risk following systematic physical activity (PA). Despite this evidence, CVD continues to rise, and public health PA initiatives often fail to demonstrate clinically relevant effects. In short, laboratory efficacy often fails to translate into real-world effectiveness. PURPOSE: We investigated the effectiveness of three physical activity interventions. We did so using a Phase-IV clinical trial model, in which all treatments were administered in uncontrolled community settings, and in which all interventions and measures were delivered by, and conducted by, community health centre staff. METHODS: Participants were sedentary individuals receiving no medication to reduce CVD risk (n=238, age 43±5 years). Participants selected a PA or exercise (EX) pathway. Those who selected PA were randomised to either fitness centre based PA counselling delivered by an exercise professional (PAC) or a wait-list control condition (CONT). Those who selected EX were randomised to either a structured exercise program (STRUC) or unstructured fitness centre use (FREE). Measures were mean arterial pressure (MAP: mmHg) estimated using the formula Diastolic Blood Pressure (BP) + (0.33 x (Systolic BP – Diastolic BP)), and total cholesterol (TC: mmol/L). Measures were taken at baseline and 48 weeks. Data were analysed using paired-sample t-tests. RESULTS: Data analysis for cholesterol indicated a small but statistically significant increase in TC in CONT (M=0.8%, SD=0.5, p = .005). TC was however approximately equivalent to baseline in PAC and FREE and reduced, although not significantly, in STRUC. Data for blood pressure indicated a statistically significant decrease in MAP in STRUC (M=2.5%, SD=8.3, P = .004). MAP was reduced, although not significantly, in all other treatments and CONT. CONCLUSIONS: Data suggest that over 48 weeks, all forms of exercise might be effective in offsetting increases in total cholesterol associated with inactivity. Furthermore, a structured exercise programme might be more effective than either unstructured exercise or physical activity counselling in reducing mean arterial blood pressure.