Energy depot replenishment in rats during refeeding after fasting: effect of exercise.

The effect of progressive moderate exercise on body weight gain, visceral and muscle protein stores, and thyroid hormone levels during an 8-day refeeding period after 65 h of starvation was studied in 2-month-old male Sprague-Dawley rats. Twenty-four animals were divided into three groups and acclimated for 5 days while being fed with ordinary Purina Chow. After the fasting phase, a group of rats was killed in order to provide base-line information concerning fasting-induced changes in body composition; a sedentary group was fed Purina Chow ad libitum; and a treadmill-exercised group was pair fed with the sedentary rats. During the refeeding phase, the exercised animals regained significantly less weight than the sedentary animals (p less than 0.001), but the two groups did not differ significantly with respect to visceral, muscle, eviscerated carcass, and skin protein. Total body fat content was lower in the exercised than the sedentary group. The thyroid hormone levels were not significantly different for the two refed groups. These results indicate that exercise during refeeding may alter the pattern of body weight gain during refeeding after fasting such that the replenishment of adipose tissue stores is reduced without compromising the restoration and growth of lean tissue.