ADAPTATION TO EXERCISE IN THE RAT - LACK OF ASSOCIATIVE CONTROL

A procedure in which female Long-Evans rats were swum to a criterion o f fatigue was utilized to assess the contextual determinants of adapta tion to exercise. In Experiment 1, it was observed that rats given fou r exercise exposures demonstrated significant adaptation to the treatm ent, as indicated by reliably longer swimming times over the course of exercise exposure. Furthermore, the change in swimming times reflecte d in these subjects was not due to maturation or growth over the cours e of the experiment, as their body weights before and after the experi ment did not reliably differ. Experiment 2 addressed whether adaptatio n to swimming exercise was susceptible to a context shift effect, as i s tolerance to drugs and adaptation to other homeostatic disturbances (e.g., hypothermia). Using a within-subject design, Experiment 2 demon strated that a shift in contextual stimuli (a procedure that reliably disrupts drug tolerance and hypothermia adaptation) failed to disrupt established adjustment to exercise. The results of these experiments s uggest that adaptation to exercise may be mediated by different mechan isms than adaptation to other disturbances (e.g., drugs, hypothermia), since an alteration in contextual stimuli did not appear to be detrim ental to established exercise adaptation with this paradigm.