Nutritional status and spontaneous locomotor activity in the rat.

A considerable amount of energy may be saved by lowering the spontaneous locomotor activity when energy intakes are reduced. The results of the present study in rats undernourished for a period of 21 or 60 days and subsequently fed ad libitum diet did not show any differences in activity when compared to their respective control groups, either during the undernourished periods or well fed states. Although this would mean that the rats are not economising energy on activity, it is probable that these rats with lower body weights are contributing to energy saving mechanism by reducing the cost of activity per se since the cost of activity and body weight are directly related.