MEDFORD, Mass., Aug 18, 2009 (UPI via COMTEX) -- Exercise is always being
advised for good health but a study in rats found extreme exercise may be
physically addicting, U.S. researchers found.
Lead author Robin Kanarek of Tufts University said excessive running shares
similarities with drug-taking behavior.
"As with food intake and other parts of life, moderation seems to be the key,"
Kanarek says in a statement. "Exercise, as long as it doesn't interfere with
other aspects of one's life, is a good thing with respect to both physical and
mental health."
The study involved 44 male and 40 female rats that were allowed either to run in
exercise wheels or remain inactive.
To simulate anorexia athletica -- exercise addiction -- the researchers divided
the active and inactive rats into groups whose members were either given food
for one hour a day or around the clock. Rats in all four groups were then given
naloxone, a medicine for heroin overdose that produces immediate withdrawal
symptoms.
The study, published in Behavioral Neuroscience, found active rats showed
withdrawal symptoms like those seen in narcotics addicts, while the active rats
who had access to food for only one hour a day both ran the most and displayed
the most severe withdrawal symptoms.
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