Association between change in cardiorespiratory fitness and incident hypertension in Swedish adults

Aims: To explore how change in cardiorespiratory fitness is associated with incident hypertension in adults, and whether the association varies between sex, age, body mass index, cardiorespiratory fitness at baseline and follow-up time. A second aim is to study how change in other lifestyle-related variables affects the results.

Methods: A total of 91,728 participants (48% women), normotensive at baseline, with two examinations from occupational health service screenings between 1982 and 2019 (mean duration 4.3 years) were included. Cardiorespiratory fitness was assessed as estimated maximal oxygen consumption using submaximal cycle testing. Change in cardiorespiratory fitness was expressed as the percentage change per year. Incident hypertension was defined as systolic blood pressure of 140 mmHg or greater or diastolic blood pressure of 90 mmHg or greater, or self-reported physician-diagnosed hypertension, at second examination.

Results: A large increase (≥3% annual change) in cardiorespiratory fitness was associated with a 11% lower risk of incident hypertension compared with maintainers (-1 to +1%), after multi-adjustment including change in smoking, body mass index, diet, stress and exercise habits. On the contrary, a small (-1 to -<3%) and large (≥-3%) decrease in cardiorespiratory fitness associated with a 21% and 25% higher risk compared with maintainers. Longer duration between the examinations was associated with stronger risk associations. Preserving, or changing to, risk level for the other lifestyle variables was associated with a higher risk of incident hypertension. However, a simultaneous maintenance of or increase in cardiorespiratory fitness attenuated the risk associated with smoking, and stress.

Conclusion: Preserving or increasing cardiorespiratory fitness should be part of any long-term strategy to decrease the risk of incident hypertension.