The purpose of this experiment was to inform and gather information on healthy rats and how exercise affected their longevity. They had different groups of rats which were separated into a voluntary exercise group (32 rats), sedentary freely eating (54 rats), and a paired-weight group whose food intake was monitored to maintain the same body weight as those of the runners (54 rats).
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The rats chosen for this experiment were males from the Charles River. Five percent of these rats were randomly selected then killed to examine their bodies to make sure there were no pathogens. The remaining rats were kept in a sterile environment until the results came back that there were no pathogens present. The rat workers were not allowed to work with any other rats during the experiment or in any other areas where they would be exposed to other rats. Although all the rats were kept in the same room they were in separate cages according to the groups that they were assigned. The active rats had a tachometer attached to their cage in order to keep track of their activity. After the first three weeks of the experiment the active rats were running two-seven miles/day and at that rate their weight was steady on an ad libitum diet (all you can eat). They did notice however that after four to six months that the runners lost interest in exercising and quickly dropped the amount they ran. They did discover that if they gave the rats a little less food then their usual ad libitum diet that it reversed the decrease in their running. According to the experiment food restriction can increase life-span in rats. The food intake of the sedentary rats was recorded daily for one week for ten rats, and then it rotated and recorded the next ten rats' food intake and so on until they recorded them all.
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As discussed earlier, results showed after three weeks the rats increased their running to somewhere between two-seven miles/day, after four to six months the runners lost interest in running so in order to compensate they reduced their food intake slightly to roughly 92% of what they were eating and this reversed the decrease in running.