Cardiorespiratory Fitness is Associated with Reduced Risk of Respiratory Diseases in Middle-Aged Caucasian Men: A Long-Term Prospective Cohort Study

Cardiorespiratory fitness (CRF), an index of cardiac and respiratory functioning, is strongly associated with a reduced risk of adverse health outcomes. We aimed to assess the prospective association of CRF with the risk of respiratory diseases (defined as chronic obstructive pulmonary disease, pneumonia, or asthma). Cardiorespiratory fitness, as measured by maximal oxygen uptake, was assessed in 1974 middle-aged men. During a median follow-up of 25.7 years, 382 hospital diagnosed respiratory diseases were recorded. Cardiorespiratory fitness was linearly associated with risk of respiratory diseases. In analysis adjusted for several established and potential risk factors, the hazard ratio (HR) (95% CI) for respiratory diseases was 0.63 (0.45-0.88), when comparing extreme quartiles of CRF levels. The corresponding multivariate adjusted HR (95% CI) for pneumonia was 0.67 (0.48-0.95). Our findings indicate a graded inverse and independent association between CRF and the future risk of respiratory diseases in a general male Caucasian population.