Exercise Can Help Overcome Addiction

A new study finds that exercise—a good mix of jogging, walking, and resistance training—can significantly help people who are addicted to methamphetamine. Exercise combined with traditional behavioral therapy can help outrun addiction to methamphetamine.

The study, conducted by researchers at University of California, Los Angeles (UCLA), showed that those who included walking or jogging along with resistance training in their treatment had a 15% increase in the number of dopamine receptors in the brain. The dopamine system is directly impacted by meth use; restoring these receptors reduces people’s craving for the drug.

Edythe London, professor of psychiatry in the Semel Institute for Neuroscience and Human Behavior at UCLA, led the study with fellow researchers. The study is published in the journal Neuropsychopharmacology.

The study included 19 participants. Participants were randomly assigned to 2 groups and were then given positron emission tomography (PET) scans. The scans looked at dopamine receptors in the striatum (a part of the forebrain and a critical component of the reward system). The scans showed no significant difference in striatum dopamine receptors between the groups.

For 8 weeks, 10 subjects were assigned to walk or jog on a treadmill three times a week for one hour, and to do resistance training, using weight machines, free weights or both. The other 9 participants were given health education training for the same time period but did not exercise. After 8 weeks, all participants were given a second PET scan.

The results were unambiguous. The group that exercised regularly had an average increase of 15% in the number of striatum dopamine receptors. Among those who did not exercise, the average increase was just 4%.

Additionally, the differences appeared to affect other components of the striatum. Among those who exercised, the average increases in the numbers of receptors were 16% in the associative region, 16% in the sensory-motor region and 8% in the limbic region. By contrast, the group that did not exercise showed increases averaging only 5% in the limbic region, and 4% in both the associative and sensory-motor regions of the striatum.

Methamphetamine is a powerful and addictive drug that causes the brain to release a spike of dopamine. The high can last up to 6 hours. Dopamine allows cells to communicate, but it also has a role in responding to external stimuli—including drugs—providing sensations of pleasure and satisfaction. Repeated use of meth causes the dopamine system to suppress, and reduces the number of dopamine receptors.

With treatment, these receptors can recover over time, but the rate of recovery varies widely, and some deficits last well beyond the time people stop using drugs.

“Although this is a small study, it’s a very encouraging finding,” London said. “The results demonstrate that methamphetamine-associated damages to the dopamine system of the brain are reversible in human subjects, and that recovery of the dopamine system after chronic drug use can be facilitated with exercise training.”