Effect of exercise on intestinal tumour development in the male Fischer rat after exposure to azoxymethane

Thirty-two male Fischer rats were exercised in a treadmill, 2 km daily on weekdays for 38 weeks, after three subcutaneous injections of azoxymethane, 15 mg/kg body weight. Randomly selected control animals were housed in regular 38 × 22 cm cages in groups of no more than three rats per cage. All rats were allowed free access to food and water. The exercising rats ate about 20% more than the sedentary rats, but gained less weight. Fat stores were considerably smaller in the exercised rats whereas the lean body mass and ash content were similar. After 38 weeks significantly fewer rats in the exercise group had developed neoplasia of the colon mucosa.