Running and addiction: precipitated withdrawal in a rat model of activity-based anorexia

Behav Neurosci. 2009 Aug;123(4):905-12. doi: 10.1037/a0015896.


Exercise improves cardiovascular health, strengthens muscles and bones, stimulates neuroplasticity, and promotes feelings of well-being. However, when taken to extremes, exercise can develop into an addictive-like behavior. To assess the addictive potential of exercise, withdrawal symptoms following injections of 1.0 mg/kg naloxone were compared in active and inactive male and female rats. Active and inactive rats were given food for 1 hr or 24 hr/day. Additionally, a group of inactive rats was pair-fed the amount of food consumed on the previous day by food-restricted active rats. Rats fed for 1 hr/day decreased food intake and lost weight. Additionally, food-restricted active rats increased wheel running. There was a direct relationship between the intensity of running and the severity of withdrawal symptoms. Active food-restricted rats displayed the most withdrawal symptoms, followed by active rats given 24-hr access to food. Only minimal withdrawal symptoms were observed in inactive rats. These findings support the hypothesis that exercise-induced increases in endogenous opioid peptides act in a manner similar to chronic administration of opiate drugs.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Analysis of Variance
  • Animals
  • Anorexia / physiopathology*
  • Body Weight / drug effects
  • Disease Models, Animal
  • Feeding Behavior / drug effects
  • Feeding Behavior / physiology
  • Female
  • Male
  • Motor Activity / drug effects
  • Motor Activity / physiology
  • Naloxone / administration & dosage
  • Naloxone / pharmacology*
  • Narcotic Antagonists / administration & dosage
  • Narcotic Antagonists / pharmacology*
  • Physical Conditioning, Animal*
  • Rats
  • Rats, Long-Evans
  • Sex Characteristics
  • Substance Withdrawal Syndrome / physiopathology*


  • Narcotic Antagonists
  • Naloxone