The association of lung function and pulmonary vasculature volume with cardiorespiratory fitness in the community

Background Cardiorespiratory fitness is not limited by pulmonary mechanical reasons in the majority of adults. However, the degree to which lung function contributes to exercise response patterns among ostensibly healthy individuals remains unclear. Methods We examined 2314 Framingham Heart Study participants who underwent cardiopulmonary exercise testing (CPET) and pulmonary function testing. We investigated the association of forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC), FEV₁/FVC and diffusing capacity of the lung for carbon monoxide (D_LCO) with the primary outcome of peak oxygen uptake (V′_O2) along with other CPET parameters using multivariable linear regression. Finally, we investigated the association of total and peripheral pulmonary blood vessel volume with peak V′_O2. Results We found lower FEV₁, FVC and D_LCO were associated with lower peak V′_O2. For example, a 1 L lower FEV₁ and FVC was associated with a 7.1% (95% CI 5.1–9.1%) and 6.0% (95% CI 4.3–7.7%) lower peak V′_O2, respectively. By contrast, FEV₁/FVC was not associated with peak V′_O2. Lower lung function was associated with lower oxygen uptake efficiency slope, oxygen pulse slope, V′_O2 at anaerobic threshold (AT), minute ventilation (V′_E) at AT and breathing reserve. In addition, lower total and peripheral pulmonary blood vessel volume were associated with lower peak V′_O2. Conclusions In a large, community-based cohort of adults, we found lower FEV₁, FVC and D_LCO were associated with lower exercise capacity, as well as oxygen uptake efficiency slope and ventilatory efficiency. In addition, lower total and peripheral pulmonary blood vessel volume were associated with lower peak V′_O2. These findings underscore the importance of lung function and blood vessel volume as contributors to overall exercise capacity.