Exercise can be an addiction

Can’t stay out of the gym? Describe yourself as a “gym rat?” Every so often, a study is published examining exercise addiction. This particular animal study is especially interesting because of its implications for bodybuilders.

Tufts University researchers had 44 male and 40 female rats either run for several weeks on an exercise wheel or remain inactive. The rats were then divided into two groups. The first was given food for an hour a day, and the second was fed around the clock. All rats were then given naloxone, a drug that simulates immediate heroin withdrawal symptoms. After the injections, the hardest exercising rats showed the most severe withdrawal symptoms – trembling, writhing, chattering teeth and drooping eyelids. Upon the resumption of exercise, these symptoms lessened or went away. This led researchers to conclude, “Exercise, like drugs of abuse, leads to the release of neurotransmitters such as endorphins and dopamine, which are involved with a sense of reward.”


You hit the iron because you look good and it feels good – it’s the best kind of high there is. But too much exercise can get you seriously overtrained and burned out, costing you muscle now and destroying your physique in the long term. That’s something you want to avoid at all costs.


Kanarek RB, D’Anci KE, Jurdak N, Mathes WF. Running and addiction: precipitated withdrawal in a rat model of activity-based anorexia. Behav Neurosci. 2009 Aug;123(4):905-12.

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