Purpose: The cross-sectional associations of leisure-time physical activity (LTPA) and cardiorespiratory fitness with the metabolic syndrome (MS) were investigated in a population-based sample of 1069 middle-aged men without diabetes, cardiovascular disease, or cancer.
Methods: LTPA was assessed using a detailed quantitative questionnaire. Maximal oxygen uptake VO(2max) and core and related features of the MS were determined. A modified World Health Organization definition of the MS and factor analysis were used.
Results: Men who engaged in at least moderate-intensity (>or=4.5 metabolic equivalents) LTPA <1.0 h.wk-1 were 60% more likely to have the MS than those engaging in >or= 3.0 h.wk-1 even after adjustment for confounders. Low-intensity (<4.5 metabolic equivalents) LTPA was not associated with the metabolic syndrome. Men with a VO(2max) <29.1 mL x kg-1 x min-1 were almost seven times more likely to have the MS than those with a VO(2max) >or=35.5 mL.kg-1.min-1 even after adjusting for confounders. In first-order factor analysis using a promax rotation, the principal factor explained 20% of total variance and had heavy loadings for VO(2max) (-0.57) and at least moderate-intensity LTPA (-0.44), and moderate or heavy loadings for the main components of the MS. The second-order factor analysis generated a principal factor that was strongly loaded on by the main components of the MS and VO(2max) (-0.50) but not LTPA.
Conclusion: A sedentary lifestyle and especially poor cardiorespiratory fitness are not only associated with the MS but could also be considered features of the MS. Measurement of VO(2max) in sedentary men with risk factors may provide an efficient means for targeting individuals who would benefit from interventions to prevent the MS and its consequences.