Obesity and Ventilatory Responses During Exercise in the Fitness Registry and the Importance of Exercise National Database (FRIEND)

T. G. Bissen, Cardiovascular and Applied Physiology Laboratory, Florida State University,FL, USA.
R. Arena, M. P. Harber, L. A. Kaminsky, J. Myers and J. C. Watson

Scand J Med Sci Sports 2026 Vol. 36 Issue 3 Pages e70264

A high minute ventilation/rate of carbon dioxide production (V̇E/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 V̇E/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 V̇E/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 V̇E/V̇CO2 slope between adults with and without obesity (BMI </≥ 30 kg/m2). Partial correlation adjusted for age, sex, race/ethnicity, and cardiorespiratory fitness was used to determine the relation between the V̇E/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. V̇E/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, F4,3529 = 134, p < 0.001). V̇E/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 V̇E/V̇CO2 slope in the FRIEND Registry.