Effects of Continuous and Accumulated Exercise on Endothelial Function in Rat Aorta

BACKGROUND: The practice of exercise in short bouts repeated throughout the day may be an alternative strategy to lift people out of physical inactivity. OBJECTIVE: to evaluate if accumulated exercise, as occurs in continuous exercise training, improve endothelial function in rat aorta. METHODS: Wistar male rats were divided into three groups: continuous exercise (CEx, 1 hour on the treadmill) or accumulated exercise (AEx, 4 bouts of 15 minutes / day) for 5 days/week for 8 weeks, or sedentary (SED). During the training period, body weight gain and increase in exercise performance were recorded. On sacrifice day, aorta was dissected into rings (3-5 mm) and mounted on the organ bath. RESULTS: Fitness was significantly greater in CEx and AEx rats as compared with SED animals. In addition, compared with the SED group, CEx animals had a lower body mass gain, and the aorta obtained from these animals had reduced contractile response to norepinephrine and greater acetylcholine-induced relaxation. These results were not observed in ACEx animals. CONCLUSIONS: Both CEx and AEx improved fitness, but only CEx led to reduced body weight gain and improved endothelial function.