Physical training of moderate intensity improves survival rate of diabetic rats submitted to experimental myocardial infarction.

The present study was designed to compare the effect of three programs of exercise of different intensity on the survival rate of normal and streptozotocin-diabetic rats (60 mg/kg) submitted to acute experimental myocardial infarction. The animals were trained progressively on a treadmill once a day, five days per week for eight weeks at a 10 degree incline according to one of the following treadmill running programs: light (30 mins/day at 20 m/min), moderate (30 mins/day at 25 m/min) or heavy (60 mins/day at 25 m/min). Myocardial infarction was produced by left coronary artery ligation under ether anesthesia three days after the last bout of exercise. Successful ligation was demonstrated by elevated plasma creatine kinase MB isoenzyme levels 4 h later or by dye injection in rats with early death. In sedentary diabetic rats (n = 33), the early survival rate was decreased in comparison to sedentary controls (n = 22), although statistical significance was not reached, (30 versus 45%; P = 0.1952 by Fisher's exact test). These values were not significantly modified by light or heavy training in control (light n = 18, 61%; heavy n = 25, 56%) nor in diabetic animals (light n = 28, 32%; heavy n = 23, 39%). While the survival rate was not altered by moderate exercise in control animals (n = 26, 62%), it was greatly improved in diabetic rats (n = 23, 64%, P = 0.0108 versus sedentary diabetics). These data suggest that it is possible to improve the early survival rate of diabetic rats submitted to experimental myocardial infarction by a previous training program at a moderate level of exercise.(ABSTRACT TRUNCATED AT 250 WORDS)