Effects of Long-Term Weight Training Exercise on Aging Heart in Rat

장기간 체중부하 운동훈련이 흰쥐 노화 심근에 미치는 영향

There is considerable interests in the effect of regular, vigorous exercise, in particular weight training as a possible measure in improving myocardial function. The present investigation aimed to examine possible effect of a long-term weight training program on the heart in aging rats. Male rats aged 3-,10-, and 20-month-old were divided at random into a control (sedentary) and the exercise group. The training group was exercised for 5 days a week by 1 RM of ten times with weight training apparatus. This investigation examined the changes of the heart muscle relative to histological, ultrastructural, cytochemical, and stereological studies in rats. Quantity of lipofuscin pigments was clearly increased in the weight training group of 15-month-old rats, and mitochondrial degeneration, vacuolization, and interstitial proliferation were observed as well. In the weight training group of 25-month-old rats the frequency as separated intercalated discs, fraying myofibrils and hypercontraction band increased in number compared with the same 15-mon1h-old group. From the experimental result of glucose-6-phosphatase activity, the enzyme activities decreased in the weight training group of 15-month-old rats, and more decreased in the same 25-month-old group. In stereological study, both 15- and 25-month-old training groups, mitochondrial and myofibrilar volume densities significantly decreased, whereas interstitial volume density significantly increased. From the experimental results obtained in the present study, it is suggested that long-term weight training exercise do not cause any significantly qualitative and quantitative ultrastructural change of the heart muscle in the young. On the contrary, long-term weight training exercise stress may actually induce degenerative changes in the heart muscle in the old age.

장기간 체중부하운동이 흰쥐의 심근에 미치는 효과를 규명하기 위하여 생후 3개월, 10개월 및 20개월된 흰쥐를 5개월간 운동시킨 후 각각의 비운동군과 비교하여 심근의 조직학적ㆍ세포학적 변화를 관찰하고, 심근세포내 미세구조적 변화를 입체해석학적으로 비교 분석하였다. 운동 15개월군부터 노화색소의 양이 현저히 증가되었고 사립체의 변성, 공포화 현상 그리고 간질조직의 증식이 뚜렷하였으며, 25개월군에서는 윤반분리, 근원섬유의 소실 및 과수축대 출현빈도가 증가되었다. Glucose-6-phosphatase의 활성도는 15개월 운동군에서 감소하여 25개월 운동군에서는 활성도가 거의 나타나지 않았다. 입체해석학적 결과에서도 장기간 체중부하운동으로 인해 15개월, 25개월군에서 모두 사립체와 근원섬유의 체적밀도는 감소되었고, 간질조직의 체적밀도는 증가되었다. 본 연구의 결과로 볼 때 장기간 체중부하운동은 3개월군에 있어서 심장에 미치는 역효과가 없으나 10개월군과 20개월군에서는 심근기능강화에 역효과를 초래 할 우려가 큰 것으로 판단된다.