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

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 (FEV(1)) 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 FEV(1) 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 FEV(1) 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 FEV(1) 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 FEV(1) within normal limits may influence VO(2peak) in healthy subjects even when no ventilatory limitation to exercise is evident.