Higher fitness levels yield benefits for controlling blood pressure (BP) trajectory, according to results from a recent study.

“Previous studies have demonstrated that increased cardiorespiratory fitness levels result in lowered BP in an inverse relationship that varied across age strata,” the researchers wrote. “However, little knowledge exists regarding the impact of fitness on age-associated BP changes, and the mechanism is currently unclear.”

Researchers enrolled a cohort of 13,953 men aged 20 to 90 years from the Aerobics Center Longitudinal Study. Participants had completed anywhere between three and 28 evaluations between 1970 and 2006 at the Cooper Clinic in Dallas (for a total of 56,140 observations), with fitness assessed with maximal treadmill exercise testing. Clinical evaluations included a physical examination, anthropometry measurements, fasting blood analysis, resting BP, exercise testing, and completion of a standard questionnaire on personal family medical history.

Diastolic BP increased until around age 60, according to the results, and systolic BP increased across all age periods. After adjusting for fitness level, body fat percentage, glucose, triglycerides, resting heart rate, smoking, heavy alcohol consumption, and parental history of hypertension, systolic BP increased by an average of 0.31 mm Hg (95% CI, 0.29-0.32) per year and began to become abnormal around age 50. Diastolic BP increased in a linear fashion by an average of 0.15 mm Hg (95% CI, 0.14 to 0.16) per year, becoming abnormal around age 60.

Men with higher fitness levels, however, were able to delay abnormal systolic increases compared to those with lower fitness levels. The results, the researchers wrote, underscored the importance of the effects of fitness on systolic BP over an adult lifetime.

“Promoting fitness to extend the duration of normal systolic BP levels might reduce the potential risk for developing hypertension, cardiovascular disease and other BP-related chronic diseases, as well as reduce medical costs, major morbidity, and mortality,” the researchers concluded. “Since regular physical activity is the primary and most modifiable determinant of fitness level, our results underscore the potential importance of increasing regular fitness activity to prevent the aging-related progressive rise in BP.”

In an accompanying editorial, Stanley Franklin, MD, and Gary Pierce, PhD, noted the unique relationship between fitness and the lowering of systolic BP. The absence of women in the cohort was identified as a limitation of the study, as well as a “healthy cohort effect” due to the observed group undergoing repeated cardiopulmonary testing and engaging in more regular cardioprotective fitness.

“Habitual aerobic exercise/physical activity may even counteract the burden of cardiometabolic abnormalities that accelerate artery stiffening—characterized as “early vascular aging”—and therefore, slow the onset and severity of isolated systolic hypertension,”Drs. Franklin and Pierce wrote. “Future studies should investigate fundamental mechanisms of cardiorespiratory fitness that results in “primordial” prevention of systolic hypertensions with advancing age.”

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Liu J, Sui X, Lavie C, et al. J Am Coll Cardiol. 2014;1245-53
Franklin S, Pierce G. J Am Coll Cardiol. 2014;1254-6.

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