岡元 政和, 田中 弘允, 斉藤 和人, 鹿島 友義, 金久 卓也

Masakazu OKAMOTO, Hiromitsu TANAKA, Kazuto SAITO, Tomoyoshi KASHIMA, Takuya KANEHISA

鹿児島大学医学部第一内科

The First Department of Internal Medicine, Faculty of Medicine, Kagoshima University

キーワード : athlete, supine exercise, upright exercise, Frank-Starling mechanism, recovery

In order to examine left ventricular function in athletes, M-mode echocardiographic examination was performed using a phased-array electronic sector scanner. Fifty-three male university athletes and eight athletes and non-athletes. These data suggest that the heart of athletes adapts to the stress of exercise thealthy male university students (non-athletes) were studied in the supine and upright positions at rest, during bicycle ergometric exercise and during recovery. Exercise was of 3 minutes' duration at a power output of 120 Watts.
During both supine and upright exercises, left ventricular end-diastolic dimension (Dd) increased in athletes, whereas it remained unchanged in non-athletes. Left ventricular end-systolic dimension (Ds) decreased in non-athletes, while it remained unchanged in athletes. As a result, fractional shortening of the ventricular dimension (⊿D) and ejection fraction (EF) increased inhrough the Frank-Starling mechanism, while the heart of non-athletes adapts to the stress by an increase in myocardial contractile state.
The increments of ⊿D and EF reached steady state in one minute after the beginning of exercise in athletes and two minutes in non-athletes.
Just after exercise, we could observe significant decrease in Ds and unchanged in Dd, as a result, ⊿D and EF remarkably increased in both groups.