To investigate how exercise affects the heart over time, researchers of the Massachusetts General Hospital enrolled two groups of Harvard University student athletes at the beginning of the fall 2006 semester. One group was comprised of endurance athletes – 20 male and 20 female rowers – and the other, strength athletes – 35 male football players. Student athletes were studied while participating their normal team training, with emphasis on how the heart adapts to a typical season of competitive athletics.
Echocardiography studies were taken at the beginning and end of the 90-day study period. Participants followed the normal training regimens developed by their coaches and trainers, and weekly training activity was recorded. Endurance training included one- to three-hour sessions of on-water practice or use of indoor rowing equipment. The strength athletes took part in skill-focused drills, exercises designed to improve muscle strength and reaction time, and supervised weight training. Participants also were questioned confidentially about the use of steroids, and any who reported such use were excluded from the study.
At the end of the 90-day study period, both groups had significant overall increases in the size of their hearts. For endurance athletes, the left and right ventricles expanded. In contrast, the heart muscle of the strength athletes tended to thicken, a phenomenon that appeared to be confined to the left ventricle.
The most significant functional differences related to the relaxation of the heart muscle between beats – which increased in the endurance athletes but decreased in strength athletes, while still remaining within normal ranges. While this study looks at young athletes with healthy hearts, the information it provides may someday benefit heart disease patients, the authors say.
MEDICA.de; Source: Massachusetts General Hospital