Study: exercise can protect your brain from stress-induced depression

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Scientists have found reason #5001 why exercise is so good for you.

On top of the known benefits for human health when it comes to preventing lifestyle-related diseases including heart disease, stroke, obesity and type-2 diabetes, researchers from the Karolinska Instutet in Sweden have discovered that physical exercise can protect the brain from stress-induced depression.

Published in the journal Cell, the study on mice looked at changes in skeletal muscle during exercise training and found that these changes can rid the blood of a substance that accumulates in your body during stress, and is potentially harmful to your brain.

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After exposing the mice to a stressful environment (loud noises, flashing lights and reversed circadian rhythms), researchers found that those with well-trained muscle characteristics had no depressive symptoms.

Why? “Well-trained muscle produces an enzyme that purges the body of harmful substances,” said lead researcher Jorge Ruas. “So in this context the muscle’s function is reminiscent of the kidney or the liver.”

In fact, they discovered that high levels of a specific protein in the muscle (PGC-1a1) helped convert a substance formed during stress called kynurenine (found in high levels in patients with mental illness) into kynurenic acid, a substance that can’t pass from the blood to the brain. And as it turns out, PGC-1a1 increases with physical exercise.

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“In neurobiological terms, we actually still don’t know what depression is,” said Mia Lindskog, a researcher from the institute’s Department of Neuroscience. “Our study represents another piece in the puzzle, since we provide an explanation for the protective biochemical changes induced by physical exercise that prevent the brain from being damaged during stress.”

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While there have been many studies linking the mental benefits of exercise this study shows that it can also have a “detoxification effect”, thanks to the skeletal muscle function. According to Raus, “when activated, it can protect the brain from insults and related mental illness.”

Around 45 per cent of Australians will experience a mental health condition at some point of their life, so visit beyondblue, the Black Dog Institute or Lifeline for more information on other ways to deal with depression.

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