Cardiorespiratory fitness and metabolic risk

The present study sought to evaluate the relation between cardiovascular risk factors and cardiorespiratory fitness (CRF) in a large population. Low CRF has been associated with increased total mortality and cardiovascular mortality. The mechanisms underlying greater cardiovascular mortality have not yet been determined. A series of cardiovascular risk factors were measured in 59,820 men and 22,192 women who had undergone determinations of CRF with maximal exercise testing. The risk factor profiles were segregated into 5 quintiles of CRF. With decreasing CRF, increases occurred in obesity, triglycerides, nonhigh-density lipoprotein cholesterol, triglyceride/high-density lipoprotein ratios, blood pressure, metabolic syndrome, diabetes, and cigarette smoking. Self-reported physical activity declined with decreasing levels of CRF. In conclusion, it appears likely that the enrichment of cardiovascular risk factors, especially metabolic risk factors, account for a portion of the increased cardiovascular mortality in low-fitness subjects. The mechanisms responsible for this enrichment in subjects with a low CRF represent a challenge for future research.