OBJECTIVE—To determine in normal weight, overweight, and obese men the risk of all-cause and cardiovascular disease (CVD) mortality associated with the metabolic syndrome (MetS) and the influence of cardiorespiratory fitness (CRF).

RESEARCH DESIGN AND METHODS—This observational cohort study included 19,173 men who underwent a clinical examination, including a maximal exercise test. MetS was defined according to National Cholesterol Education Program guidelines.

RESULTS—At baseline 19.5% of the men had MetS. The ORs of the metabolic syndrome at baseline were 4.7 (95% CI 4.2–5.3) in overweight and 30.6 (26.7–35.0) in obese men compared with normal weight men. A total of 477 deaths (160 CVD) occurred in 10.2 years of follow-up. The risks of all-cause mortality were 1.11 (0.75–1.17) in normal weight, 1.09 (0.82–1.47) in overweight, and 1.55 (1.14–2.11) in obese men with MetS compared with normal weight healthy men. The corresponding risks for CVD mortality were 2.06 (0.92–4.63) in normal weight, 1.80 (1.10–2.97) in overweight, and 2.83 (1.70–4.72) in obese men with the MetS compared with normal weight healthy men. After the inclusion of CRF in the model, the risks associated with obesity and MetS were no longer significant.

CONCLUSIONS—Obesity and MetS are associated with an increased risk of all-cause and CVD mortality; however; these risks were largely explained by CRF.