The association between dynamic lung volume and peak oxygen uptake in a healthy general population: the HUNT study

Abstract

Background: Although dynamic lung volume is not considered a limiting factor of peak oxygen uptake (VO_2peak) in healthy subjects, an association between forced expiratory lung volume in one second (FEV₁) and VO_2peak has been reported in a healthy population aged 69 - 77 years. We hypothesized that a corresponding association could be found in a healthy general population including young and middle-aged subjects.

Methods: In a population-based study in Norway, we investigated the association between FEV₁ above the lower limit of normal (LLN) and VO_2peak using linear regression and assessed the ventilatory reserve (VR) in healthy subjects aged 20 - 79 years (n = 741).

Results: On average, one standard deviation (SD) increase in FEV₁ was associated with 1.2 ml/kg/min (95% CI 0.7 - 1.6) higher VO_2peak. The association did not differ statistically by sex (p-value for interaction = 0.16) and was similar (0.9 ml/kg/min, 95% CI 0.2 - 1.5) in a sensitivity analysis including only never-smokers (n = 376). In subjects below and above 45 years of age, corresponding estimates were 1.2 ml/kg/min (95% CI 0.5 - 1.8) and 1.2 ml/kg/min (95% CI 0.5 - 1.9), respectively. Preserved VR (≥ 20%) was observed in 66.6% of men and 86.4% of women.

Conclusions: Normal dynamic lung volume, defined as FEV₁ above LLN, was positively associated with VO_2peak in both men and women, in never-smokers and in subjects below and above 45 years of age. The majority of subjects had preserved VR, and the results suggest that FEV₁ within normal limits may influence VO_2peak in healthy subjects even when no ventilatory limitation to exercise is evident.

Keywords: Exercise test; Forced expiratory volume; Oxygen consumption; Respiratory function tests.