Adaptation effects on activity-stress ulcers in rats.

Rats were given either seven or 14 days of experience with either restricted feeding (2 hr/day) or activity (24 hr/day of access to activity wheels with ad libitum feeding). Animals were then subjected to the activity-stress ulcer procedure involving 1 hr/day of feeding and continuous access to running wheels. Neither experience with restricted feeding nor with activity wheels attenuated gastric ulceration, indicating that adaptation did not occur. Rats with either restricted feeding experience or activity experience died faster and exhibited more frequent and more severe stomach damage relative to nonexperienced controls.