High fitness level delayed aging-related BP increase in men

Men with high levels of fitness experienced abnormal systolic BP later in life compared with men of lower fitness levels, according to new findings.

“Since regular physical activity is the primary and most modifiable determinant of fitness level, our results underscore the importance for a man to increase his regular physical activity to prevent his natural, aging-related rise in [BP],” Junxiu Liu, MD, from the department of epidemiology and biostatistics at the Arnold School of Public Health at University of South Carolina, said in a press release.

Liu and colleagues investigated whether fitness alters the aging-BP trajectory. They analyzed a cohort of men aged 20 to 90 years (n=13,953) from the Aerobics Center Longitudinal Study who did not have hypertension, CVD or cancer. Participants completed between three and 28 follow-up medical examinations between 1970 and 2006, and their fitness was measured by a maximal treadmill exercise test. They were stratified by low (n=1,532), moderate (n=5,416) or high (n=7,005) levels of fitness.

Fitness and BP

After adjustment for body fat percent, fitness, resting heart rate, glucose level, triglyceride level, cholesterol level, current smoking, heavy alcohol consumption and parental hypertension, systolic BP increased by 0.3 mm Hg (95% CI, 0.29-0.31) with each year of age, but that fitness was negatively associated with systolic BP and there was a significant interaction between age and fitness (P<.001).

Diastolic BP increased 0.14 mm Hg (95% CI, 0.13-0.15) with each year of age before age 60 years, but there was not a significant interaction between age and fitness for diastolic BP.

According to the researchers, percentage of body fat did not affect the aging-BP trajectory.

Assuming a constant body fat residual, Liu and colleagues determined that age and systolic BP interact starting at age 20 years and that fitness is a protective factor for the systolic BP aging trajectory after that age.

Abnormal systolic BP, defined as >120 mm Hg, began to occur at approximately age 50 years, but men with higher fitness levels experienced it at a later age compared with men with low fitness levels. The researchers also found that abnormal diastolic BP, defined as >80 mm Hg, began to occur at approximately age 60 years.

“To move out of the low fit category, men should do at least 150 minutes of moderate-intensity physical activity such as walking, jogging, running … weekly,” Liu said.

Potential effect

A high level of fitness may affect age-related systolic BP and pulse pressure increase “by attenuating the age-related increase in elastic artery stiffness or as reflected by lower aortic stiffness (carotid-femoral pulse wave velocity) and carotid stiffness (carotid beta-stiffness index) as demonstrated in highly fit older adults compared with their sedentary age-matched peers,” Stanley S. Franklin, MD, from the Heart Disease Prevention Program of the division of cardiology at the University of California, Irvine, and Gary L. Pierce, PhD, from the department of health and human physiology at the University of Iowa, wrote in a related editorial.

Fitness may have a different effect on the aging-BP trajectory in women, and this should be studied in the future, according to Franklin and Pierce.

For more information:

Franklin SS. J Am Coll Cardiol. 2014;64:1254-1256.

Liu J. J Am Coll Cardiol. 2014;64:1245-1253.

Disclosure: The study was funded by the NIH. One researcher reports financial ties with BodyMedia, Clarity, The Coca-Cola Co., Santech and Technogym. Franklin and Pierce report no relevant financial disclosures.