Impact of physical exercise on catechol-O-methyltransferase activity in depressive patients: A preliminary communication.

Background: Catechol-O-methyltransferase (COMT) is a catabolic enzyme involved in the degradation of bioactive molecules including the neurotransmitters epinephrine, norepinephrine, and dopamine. Higher COMT activity in depressive patients in comparison to non-depressed individuals has been reported. The effect of aerobic exercise on depressive patients has been studied and a number of researchers and clinicians believe it to be effective in the treatment of depression and to be involved in several molecular underlying mechanisms. However, the effect of physical exercise on this enzyme activity is unknown, and it remains to be elucidated if chronic exercise changes COMT activity. This randomized control trial evaluates the effects of chronic exercise on peripheral COMT (S-COMT) activity in women with depressive disorder.

Methods: Fourteen women (aged: 51.4±10.5 years) diagnosed with depression (according to International Classification of Diseases-10) were randomized to one of two groups: pharmacotherapy plus physical exercise (n=7) or only pharmacotherapy (n=7). The aerobic exercise program was supervised, lasting between 45-50min/session, three times/week for 16 weeks. Erythrocyte soluble COMT were assessed prior to and after the exercise program.

Results: Exercise group when compared to a control group presented a significant decrease (p=0.02, r=-0.535) in S-COMT activity between baseline and post-intervention.

Limitations: These data are preliminary outcomes from a small sample and should be replicated.

Conclusions: Chronic exercise therapy combined with pharmacotherapy leads to significant decrease in S-COMT activity. Our results provide evidence that exercise interferes with S-COMT activity, a molecular mechanism involved in depression.