Influence of intensity of exercise training on physical performance and myocardial morphology of female rats with type I diabetes mellitus

Materials and methods Ninety-day-old female Wistar rats were divided into three groups: exercised-control (EC; n=5), high intensity exercised-diabetic (HIED=high intensity training, 80% of the maximum speed in the stress test; n=4) and low intensity exercised-diabetic (LIED=low Intensity training, 40% of the maximum speed in the stress test; n=6). The diabetes was induced in the rats by administration of Alloxan monohydrate Sigma (ALX, 50 mg kg-1 BW). Fatigue strength test and the maximal exercise test were performed before DM induction. Fatigue strength test consisted of treadmill running at 20m/min with slope equal to 0° until the animal could not run spontaneously. Time and distance were determined at the end of the race. Maximal exercise test consisted of treadmill running with a load of 5m /min every 3 min until the animal could not run spontaneously, when it was determined the maximum load. Animals ran on a treadmill running 1 hour/day, 5 days/week for 6 weeks with a load (high or low intensity). After this period animals were sacrificed and hearts removed, weighed and prepared for histomorphometric analysis.