Sex differences and incidence of activity-stress ulcers in the rat

Female rats housed in running-wheel activity cages and fed 1 hr. daily ran significantly more than similarly housed and fed male rats. Male rats survived an average of 10 days, whereas mean survival time for female rats was 7.3 days. Experimental activity rats developed glandular stomach ulcers. Pair fed controls housed in cages without activity wheels were ulcer-free. Among experimental activity rats, there were no sex differences with respect to the number or severity of ulcers.