Obesity and Ventilatory Responses During Exercise in the Fitness Registry and the Importance of Exercise National...

A high minute ventilation/rate of carbon dioxide production (V̇_E/V̇CO₂) slope during exercise is prognostic for cardiovascular mortality among clinical populations. Obesity represents a major modifiable risk factor for cardiovascular disease. However, it is unclear whether body mass index (BMI) is associated with V̇_E/V̇CO₂ slope among apparently healthy adults. Therefore, we used the Fitness Registry and the Importance of Exercise National Database (FRIEND) to determine whether BMI is positively associated with V̇_E/V̇CO₂ slope in the context of apparently healthy adults. All participants completed a cardiopulmonary exercise test on a cycle ergometer. Linear regressions adjusted for age, sex, and race/ethnicity were used to compare the V̇_E/V̇CO₂ slope between adults with and without obesity (BMI 2). Partial correlation adjusted for age, sex, race/ethnicity, and cardiorespiratory fitness was used to determine the relation between the V̇_E/V̇CO₂ slope and BMI. All data are presented as median [IQR]. We set α a priori to < 0.05. The sample (n = 3534) characteristics were as follows: (1) age = 40 (17) years; (2) 20% female; (3) cardiorespiratory fitness = 27.8[10.8] mL O₂●kg^-1●min^-1 & 2.3[0.9] L O₂●min^-1; and (4) BMI = 26.1[5.0] kg/m². V̇_E/V̇CO₂ slope was higher in adults with obesity 25.0[3.5] compared to those without obesity 24.7[3.6] with a negligible effect size (R² = 0.132, adjusted R² = 0.131, F_4,3529 = 134, p < 0.001). V̇_E/V̇CO₂ slope was weakly associated with BMI across the cohort (ρ = 0.079, p < 0.001). Obesity was positively, but negligibly, associated with a higher V̇_E/V̇CO₂ slope in the FRIEND Registry.