Maintaining or increasing cardiorespiratory fitness is associated with reduced hospital admission rate

Aims The aim of this study was to investigate the association between change in cardiorespiratory fitness (CRF) and cardiovascular disease (CVD)-related and all-cause hospital admission and explore if the association varies dependently on prior admission, baseline CRF, sex, and age.Methods and results A total of 91 140 adult participants (41.5% women) with two examinations from occupational health profile assessments between 1986 and 2019 were included (mean of 3.2 years between examinations). Cardiorespiratory fitness was assessed as maximal oxygen consumption and estimated through a submaximal cycle test. Cardiorespiratory fitness change was defined as annual percentage change in relative CRF (mL/min/kg) and further divided into 'decliners' (<= 1%), 'maintainers' (-1% to 1%), and 'increasers' (>1%). Hospital admissions were followed over a mean of 7 years. Natural cubic splines and Cox proportional hazards model were applied. Additionally, prevented fraction for the population was calculated. Increase in CRF was associated with a lower risk of CVD [hazard ratio (HR) = 0.99] and all-cause hospital admission (HR = 0.99), after multilevel adjustment for confounders and change in smoking, diet, and stress. Compared with a decline, maintenance of CRF was associated with 9% and 7% lower risk of CVD and all-cause admission, respectively. Increase in CRF reduced the risk by 13% and 11% and, for individuals with prior admission, by 20% and 14%. The burden of CVD and all-cause admission was 6% and 5% lower than if the whole cohort had declined CRF, with large potential cost savings.Conclusion Efforts to maintain or improve CRF should be included in disease-preventive strategies, regardless of change in other lifestyle-related risk factors. Preventing the age-associated decline in CRF can lessen healthcare utilization and costs.