CHICAGO—While the impact of football on health outcomes has focused largely on head injuries, new findings suggest that football training may also lead to pre-hypertension.
Rory B. Weiner, MD, a clinical and research fellow in cardiology at Harvard Medical School and Massachusetts General Hospital in Boston, and colleagues prospectively followed a group of college-age football players over a three-month period during their first-year of participation in a U.S. National College Athletic Association (NCAA) Division-I program. College students who participate in NCAA Division-I programs are considered to be at the highest level in their particular sport.
Results in 86 players who completed a full season revealed that while only two players (2%) had systolic blood pressure (BP) above 130 mm Hg at the start of the season, 31 (36%) had systolic BP above 130 mm Hg at season’s end. Additionally, resting systolic BP increased from a mean of 116 mm Hg to 124 mmHg. Systolic BP between 120 and 139 mm Hg are considered pre-hypertensive, according to The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7).
Several players had evidence of concentric left ventricular (LV) hypertrophy.
“Our findings show that we are identifying a cardiovascular risk factor in a young, otherwise healthy population,” Dr. Weiner said.
The data were reported at the American Heart Association Scientific Sessions 2010.
Typically, patients with pre-hypertension are advised to make lifestyle changes involving diet and exercise. “While the blood pressure changes we saw are not enough to require medication, lifestyle changes are important to prevent progression to hypertension,” he added.
He was quick to emphasize, however, that it is not yet known whether “de-training” after their college football training ends will cause a regression in players’ BP levels as well as their cardiac structural changes.
Future research is also needed to address whether the blood pressure surge observed during three months’ training will increase future cardiovascular disease risk, he added.
The investigators examined anthropometric measurements, resting vital signs, medical history, and echocardiographic measures of LV structure before and after players had completed their first three-month training season.
Players who had a lineman field position were more likely to experience a significant BP increase. “These players tend to be heavier and perform less endurance activity than players in non-lineman positions,” Dr. Weiner said.
More than a third of players had concentric LV hypertrophy, as evidenced by echocardiographic increase in LV mass and wall thickness, at the end of the training period.
Dr. Weiner said that more studies are needed to identify mechanisms for the BP increase. One theoretical mechanism is remodeling of the vascular wall due to repetitive exposure to high BP during weight training. “We capture the athletes at a time of relative cardiac plasticity, when they are transitioning to higher levels of collegiate athletic training which potentially increases the likelihood of cardiac remodeling,” he said.
Finally, he noted that it is possible that other sports which require isometric training may also lead to pre-hypertension.