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 animals grow old. A cohort of male and female Lou/c/jall rats was regularly submitted to an exercise throughout their life (6 consecutive days of moderate intensity training (3 x 15 min/day)). Caloric intake and macronutrients selection 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 composition (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-dependant loss of capacity of adjusting feeding behavior to metabolic needs when animals grow old, may be due to a deterioration of the central control of food intake. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.