Introduction: Many studies suggest that cardiorespiratory fitness, measured as peak oxygen uptake (VO2peak), may be the single best predictor of cardiovascular morbidity and premature cardiovascular mortality. However, current reference values are either estimates of oxygen uptake or come from small studies, mainly of men. Therefore, the aims of this study were to directly measure VO2peak in healthy adult men and women and to assess the association with cardiovascular risk factor levels.
Methods: A cross-sectional study of 4631 volunteering, free-living Norwegian men (n = 2368) and women (n = 2263) age 20-90 yr. The data collection was from June 2007 to June 2008. Participants were free from known pulmonary or cardiovascular disease. VO2peak was measured by ergospirometry during treadmill running. Associations (odds ratios, OR) with unfavorable levels of cardiovascular risk factors and a cluster of cardiovascular risk factors were assessed by logistic regression analysis.
Results: Overall, mean VO2peak was 40.0 ± 9.5 mL·kg(-1)·min(-1). Women below the median VO2peak (<35.1 mL·kg(-1)·min(-1)) were five times (OR = 5.4, 95% confidence interval = 2.3-12.9) and men below the median (<44.2 mL·kg(-1)·min(-1)) were eight times (OR = 7.9, 95% confidence interval = 3.5-18.0) more likely to have a cluster of cardiovascular risk factors compared to those in the highest quartile of VO2peak (≥40.8 and ≥50.5 mL·kg(-1)·min(-1) in women and men, respectively). Each 5-mL·kg(-1)·min(-1) lower VO2peak corresponded to ∼56% higher odds of cardiovascular risk factor clustering.
Conclusions: These data represent the largest reference material of objectively measured VO2peak in healthy men and women age 20-90 yr. Even in people considered to be fit, VO2peak was clearly associated with levels of conventional cardiovascular risk factors.