June 15, 2009

FeatureWorking Out Relieves Depression and Boosts Brain Cells

People who work out on a regular basis tend to feel bad when they miss their daily exercise. Exercise has antidepressant effects and Astrid Bjornebekk’s rat study at the Karolinska Institue in Sweden is helping to explain why. In her experiments, both exercise and antidepressants increased the formation of new cells in an area of the brain that is important to memory and learning, the hippocampus.

The hippocampus of the brain has long been associated with reward centers for thirst, hunger, and other needs. Exercise has long been known to give people a boost in spirit! Bjornebekk has evidence that exercise can have an antidepressant effect for a range of mild to moderately severe depression. If a person is taking antidepressants for depression, the addition of exercise can add a boost to their medication. "What is interesting is that the effect of antidepressant therapy can be greatly strengthened by external environmental factors," Bjornebekk says.

The Swim Test!

To test the affect of exercise on depression, Bjornebekk used experimental rats that were genetically engineered to behave as if they were depressed. For 30 days, one experimental group of depressed rats and one group of the control rats had access to running wheels on which they could exercise. Another set of experimental and control rats did not have access to running wheels.

To determine if running changed the mood of the depressed rats, a standard “swim test” was used. The more the rat is in good spirits, the more it will swim around in the water. Conversely, the more the rat is depressed, the more it will stay still in the water.

Bjornebekk found that the depressed rats that had 30 days to exercise on the running wheel were active swimmers unlike the depressed rats who did not have access to running wheels. In fact, depressed rats that got exercise had similar results to the control rats.

How Does This Work?

It is known that the hippocampus in a human brain gets smaller in depressed people. It is thought that the decrease in the size of the hippocampus causes some of the mental problems linked to depression. “The hippocampus formation is one of the regions they have actually seen structural changes in depressed patients,” Bjornebekk said.

When Bjornebekk examined the hippocampus of the depressed rats that had exercised, she found that the number of neurons in the hippocampus had increased dramatically. The running wheel exercise had a similar effect on new cell growth as compared to using a common antidepressant, selective serotonin reuptake inhibitor (SSRI).

Exercise as Therapy for Depression

Can depressed people find additional help in exercise? Bjornebekk’s study suggests that they can. It also give us a clue to the underlying biological effects of exercise on depression. The study shows that exercise has a similar action on the hippocampus as do prescription drugs on depression. Exercise, so important in many areas of our health, can help to keep us happy, too.

More to Explore

Check out the following sites read more about Dr. Bjornebekk’s discovery.

• Science Daily
• Eureka Alert
• Karolinska Institute Publication

Last updated June 15, 2009 | Comments (12) | Permalink | Feature