Long-term Change in Cardiorespiratory Fitness and All-Cause Mortality: A Population-Based Follow-up Study

Few studies have investigated long-term changes in cardiorespiratory fitness (CRF), defined by indirect measures of CRF, and all-cause mortality. We aimed to investigate whether long-term change in CRF, as assessed by the gold standard method of respiratory gas exchange during exercise, is associated with all-cause mortality. A population-based sample of 579 men aged 42 to 60 years with no missing data at baseline examination (V1) and at reexamination at 11 years (V2) were included. Maximal oxygen uptake (VO_2max) was measured at both visits using respiratory gas exchange during maximal exercise testing, and the difference (ΔVO_2max) was calculated as VO_2max (V2) − VO_2max (V1). Deaths were ascertained annually using national death certificates during 15 years of follow-up after V2. The mean ΔVO_2max was −5.2 mL/min*kg. During median follow-up of 13.3 years (interquartile range, 12.5-14.0 years), 123 deaths (21.2%) were recorded. In a multivariate analysis adjusted for baseline age, VO_2max, systolic blood pressure, smoking status, low- and high-density lipoprotein cholesterol and triglyceride levels, C-reactive protein level, body mass index, alcohol consumption, physical activity, socioeconomic status, and history of type 2 diabetes mellitus and ischemic heart disease, a 1 mL/min*kg higher ΔVO_2max was associated with a 9% relative risk reduction of all-cause mortality (hazard ratio, 0.91; 95% CI, 0.87-0.95). This study suggested that in this population, long-term CRF reduction was associated with an increased risk of mortality, emphasizing the importance of maintaining good CRF over the decades.