INFLUENCE OF CHRONIC UNDERNUTRITION ON OXYGEN-CONSUMPTION OF RATS DURING EXERCISE

Abstract

Endurance swimming times and O2 consumption during strenuous exercise were measured in age-paired undernourished rats. The animals received restricted or unrestricted amounts of 27, 15 or 8% casein diets for 10 wk. Endurance times of energy-restricted animals were similar to that of controls, despite a 2-fold weight difference. Endurance time of the protein-restricted group (8% casein) was longer than that of any other group, including energy-restricted groups identical in weight. O2 consumption of the protein-restricted group during a non-endurance swim was significantly greater than any of the other groups but was the same as that of the other undernourished groups during the endurance swim. O2 consumption by all undernourished groups was higher than that of controls during the endurance swim. Results of endurance swimming tests show that restriction of protein or energy intake may influence exercise performance differently, and differences in work performance cannot be explained by differences in body weight. Measurements of O2 consumption during swimming suggest that differences in performance are related to altered metabolic requirements resulting from dietary restrictions.