It's no secret that regular exercise can help protect you from depression. Authors of a new study published in the journal Cell believe they've found the reason why. The secret, they say, is found in a muscle enzyme called PCC-1alpha.

Gretchen Reynolds of The New York Times explains:

"A wealth of earlier research by these scientists and others had shown that aerobic exercise, in both mice and people, increases the production within muscles of an enzyme called PGC-1alpha. In particular, exercise raises levels of a specific subtype of the enzyme known unimaginatively as PGC-1alpha1. The Karolinska scientists suspected that this enzyme somehow creates conditions within the body that protect the brain against depression."

To test this hypothesis, researchers at the Karolinska Institute in Stockholm bred special mice with abnormally high levels of PGC-1alpha1. (Scientists had previously taken another set of mice and made them "depressed" by exposing them over time to stimuli that caused the mice to lose weight and exhibit dispirited behaviors) The newly bred group displayed a boosted resilience to the noticeable effects of depression. 

The researchers then tested humans and found similar results: building up PGC-1alpha1 helped ward off depression. Whether exercising can be proven to help treat people already depressed remains to be seen, though one of the researchers told Reynolds that he's confident it would.

Read more at The New York Times

Read the whole study here

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