Does fitness improve the cardiovascular risk profile in obese subjects?

Good cardiorespiratory fitness has been suggested to reduce the risk of cardiovascular disease in obesity. We explored the association of fitness with the prevalences of major cardiovascular risk factor like hypertension (HT), diabetes and metabolic syndrome (MetS) in overweight and obese subjects.

Clinical data from 491 participants in the FAT associated CardiOvasculaR dysfunction (FATCOR) study were analyzed. Physical fitness was assessed by ergospirometry, and subjects with at least good level of performance for age and sex were classified as fit. HT subtypes were identified from clinic and 24-h ambulatory blood pressure in combination. Diabetes was diagnosed by oral glucose tolerance test. MetS was defined by the American Heart Association and National Heart, Lung and Blood Institute criteria. The participants were on average 48 years old (60% women), and mean body mass index (BMI) was 32 kg/m². 28% of study participants were classified as fit. Fitness was not associated with lower prevalences of HT or HT subtypes, diabetes, MetS or individual MetS components (all p > 0.05). In multivariable regression analysis, being fit was characterized by lower waist circumference, BMI < 30 kg/m², non-smoking and a higher muscle mass (all p < 0.05).

In the FATCOR population, fitness was not associated with a lower prevalence of major cardiovascular risk factors like HT, diabetes or MetS. Given the strong association of cardiovascular risk factor burden with risk of clinical cardiovascular disease, these findings challenge the notion that fitness alone is associated with lower risk of cardiovascular disease in obesity.