Physical fitness matters more than physical activity in controlling cardiovascular disease risk factors

Background Physical activity (PA) and physical fitness (PF) are inversely associated with the clustering of cardiovascular disease (CVD) risk factors (RF) associated with the metabolic syndrome (MS). However, the role of individual components of PA, that is, intensity, duration and volume, and the inter-relationship with PF in the prevention of the MS and its individual components remains elusive. Design Cross-sectional analysis. Methods The study was based on 1298 (874 male and 424 female) police employees (aged 18-62 years) who participated in the Utrecht Police Lifestyle Intervention Fitness and Training study. PA was assessed with an extensive questionnaire. Peak oxygen uptake and metabolic markers, including blood pressure, fasting glucose, triglycerides, high-density lipoprotein cholesterol and waist circumference, were determined. Results The prevalence of the MS was 18.6% (22.5% in men, 10.6% in women). After adjustment for age and sex, average PA intensity, PA duration, PA volume and PF were each associated with reduced odds of MS. Regression analyses further showed an inverse relation between total CVD risk score and average PA intensity, the hours of PA performed at high intensity (>6 metabolic equivalent values) and PF, but no relation with total hours or the hours of PA performed at low or moderate intensity. When we adjusted our analyses for PF, the relations with the components of PA became nonsignificant. Using pathway analysis, we found that peak oxygen uptake mediated 78% of the effect of average PA intensity and 93% of the effect of the hours performed at high intensity on total CVD risk score. Conclusion PA and PF are inversely associated with the clustering of metabolic abnormalities. With regard to PA, it seems that intensity and more specifically higher intensity is the main characteristic of PA determining its effect on CVD RF. However, compared with PA, PF exerts greater effects on each of these individual CVD RF and its combination. Eur J Cardiovasc Prev Rehabil 16:677-683 (C) 2009 The European Society of Cardiology