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Excessive Exercise as an Addiction: A Review

Theories regarding how exercise can become addictive, and studies of withdrawal from exercise are reviewed. Several phsiological mechanisms, including endogenous opioids, catecholamines, and dopamine pathways, have been implicated in exercise dependence. The higher levels of endogenous opioids found following strenuous exercise, has prompted researchers to suggest that a form of auto-addiction to these hormones might be responsible for continued excessive exercising in humans. As well, investigators have suggested that, exericise dependence could be the result of a dependence on the exercise stimulated release of catecholamines, resulting in an over-arousal of the sympathetic nervous system. Moreover, the increased stimulation of dopaminergic brain structures by exercise, and the likely involvement of these structures in behavioural and pharmacological addictions, could provide another explanation for exercise-dependent behaviour. Finally, reports of withdrawal symptoms following cessation of regular exercise, has led investigators to propose that exercise can, like pharmacological and other behavioural stimuli, become addictive.