[Effect of regular physical exercises on cardiac resistance to ischemia].

The experiments were performed in rats to assess the effects of regular physical exercises (swimming and running) on cardiac responses to ischemia. The regular exercises aimed at increasing the glycolytic capacity of the muscle and causing no substantial cardiac hypertrophy were found to elevate cardiac resistance to ischemia. They also enhanced cardiac responses to catecholamines as manifested by higher activity of ATP-consuming and resynthesizing mechanisms. With these changes, ischemia caused a more rapid ATP drop in the myocardium and development of its contracture than in untrained animals.