A moderate swimming exercise regularly performed throughout the life induces age and sex-related modifications in adaptive macronutrients choice

The ability of laboratory rats to adapt food intake to needs is well-known. The present study investigates changes in this adaptive behavior when anim als grow old. A cohort of male and female Lou/c/jall rats was regularly sub mitted to an exercise throughout their life (6 consecutive days of moderate intensity training (3 x 15 min/day)). Caloric intake and macronutrients se lection during exercise and post-exercise periods were compared to the pre- training period. During swimming, a decrease in both caloric intake and fat selection was observed and an increase in protein intake was specifically seen in female groups. However, males were unable to modify the diet compos ition (macronutrient rate) from 16 months of age, whereas females were able to do it until 24 months of age. The present results suggest a sex-dependa nt loss of capacity of adjusting feeding behavior to metabolic needs when a nimals grow old, may be due to a deterioration of the central control of fo od intake. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.