Non-Exercise Estimated Cardiorespiratory Fitness and Incident Hypertension

Background: The purpose of the current study is to examine the association between non-exercise estimated cardiorespiratory fitness and incident hypertension by sex. Methods: A total of 5513 participants (4403 men and 1110 women) free of hypertension from the Aerobics Center Longitudinal Study were followed for incident hypertension, which was determined as resting systolic or diastolic blood pressure at least 130/80 mm Hg or physician diagnosis. Non-exercise estimated cardiorespiratory fitness was estimated in metabolic equivalents (METs) with sex-specific algorithms. Age, body mass index, waist circumference, and resting heart rate were used as continuous variables, whereas being physically active and current smoking were dichotomous variables. Multivariable Cox regression models were used to examine the association between cardiorespiratory fitness and risk of developing hypertension. Hazard ratios and 95% confidence intervals (CIs) were reported as an index of strength of association. Results: During an average follow-up of 5 years, 61.7% of men and 39.5% of women developed hypertension. In men, the upper and middle tertiles of cardiorespiratory fitness had 22% (95% CI, 0.71-0.86) and 10% (95% CI, 0.82-0.99) lower risk, respectively, of developing hypertension compared with those in the lower tertile. In women, the upper and middle tertiles of cardiorespiratory fitness had 30% (95% CI, 0.55-0.88) and 6% (95% CI, 0.74-1.18) lower risk, respectively, of developing hypertension. Each 1-MET increment was associated with a 10% higher risk of incident hypertension in the overall sample. Conclusion: Cardiorespiratory fitness estimated using a non-exercise algorithm is inversely associated with risk of developing hypertension in men and women.