The effects of energy (carbohydrate) restriction and vitamin E supplementation on some exercise-induced metabolic modifications in rats were studied. Male Wistar, eleven-week old rats were fed control, or restricted amounts of a modified control, or control plus vitamin E diets. After feeding the diets for five months, the animals in each group were divided into exercised and non-exercised categories. Before being killed, the rats of the exercised category were required to run on a treadmill to exhaustion. Hepatic and muscular glycogen, plasma glucose, plasma insulin and blood lactate were determined and the time to reach exhaustion was registered. Energy restriction increased hepatic glycogen and resistance to exhaustive exercise and, associated to exercise, lowered the plasma glucose levels. Vitamin E supplementation decreased the resistance to exhaustion in the exercised animals, when compared to energy restriction, but this reduction was not significant in relation to control diet. These results indicate that energy restriction improved physical performance, but vitamin E supplementation did not present the same effect.
energy restriction; vitamin E; exercise; glycogen; performance
