Researchers are beginning to understand the preciseimpact various forms of exercise have on the heart.

Scientists at Massachusetts General Hospital have found that 90 days of athletic training produces significant changes in cardiac structure and that the type of change varies with the type of exercise performed. Their findings - which may some day benefit heart disease patients - appear in this month's Journal of Applied Physiology.

The researchers studied two groups of student athletes at Harvard: endurance athletes - 20 male and 20 female rowers; and strength athletes - 35 male football players.

Echocardiography studies - ultrasound examination of the heart - were taken at the beginning and end of the period. Participants followed normal training regimens.

Both groups had significant overall increases in the size of their hearts. For endurance athletes, the left and right ventricles - the chambers that send blood into the aorta and to the lungs, respectively - expanded. The heart muscle of the strength athletes, however, 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.

研究人员已经开始了解不同运动形式对心脏的确切影响。

马萨诸塞州总医院(Massachusetts General Hospital)的科学家们发现，90天的运动训练会对心脏的结构产生明显影响，并且变化的形式与运动形式相关。他们的这一发现刊登在了本月的《应用生理学杂志》(Journal of Applied Physiology)上，或许未来会有助于心脏病患者的治疗。

研究人员以哈佛(Harvard)的两组学生运动员为研究对象：一组是耐力运动员，20名男性赛艇运动员和20名女性赛艇运动员；一组是力量运动员，35名男足运动员。

在研究期的始末都对心脏进行了超声波检查。研究对象均按正常训练计划进行训练。

两组运动员的心脏大小总体上都有明显的增加。耐力运动员的左右心室（分别负责将血液输送到大动脉和肺）均有所扩张；力量运动员的心肌则有所变厚，这似乎仅限于左心室。

不过，最显著的功能性差异在于心跳之间的心肌放松--耐力运动员的心肌放松增加了，而力量运动员则减少了。
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