Changes in cardiorespiratory fitness predict incident hypertension: A population-based long-term study

Objectives: We investigated whether long-term changes in cardiorespiratory fitness (CRF) predict the risk of incident hypertension, independent of risk factors, in initially normotensive men. Methods: This prospective study from the Kuopio Ischemic Heart Disease Study included 431 male participants without hypertension who underwent symptom-limited maximal cardiopulmonary exercise testing at baseline and during a second examination, 11-years later, who were re-evaluated for hypertension at 20-year follow-up. Changes in CRF (%) were calculated as the difference in directly measured maximal oxygen uptake (VO_2max) between the baseline and second examination, and classified into decreasing tertiles as percentages. Hypertension was defined as systolic and/or diastolic blood pressure ≥140/90 mmHg or hypertension that required antihypertensive medication as diagnosed by a physician. Results: During a 10-year follow-up after the second examination, 165 men (38%) developed hypertension. Men who demonstrated the largest decline in CRF between evaluations (−62.1% to −20.2%) had a 4.33-fold (95% CI 2.32–8.07, P <.001) risk of incident hypertension compared to men with the smallest decrease or improvement in CRF (−8.8% to 82.0%), after adjusting for age, follow-up duration, alcohol consumption, cigarette smoking, serum low and high density lipoprotein cholesterol, body mass index, daily energy expenditure (kcal) via physical activity, glomerular filtration rate, and baseline systolic blood pressure and VO_2max. Conclusions: The present findings indicate that more marked decreases in measured CRF over time are independently associated with the risk of incident hypertension in men, suggesting that CRF should be considered a causal risk factor to predict future hypertension.