Physical exercises can fight stress-induced depression

A new study has demonstrated that doing physical exercises on a regular basis helps protecting the brain from stress-induced depression.

The study conducted at Karolinska Institutet in Sweden showed that exercise training induced changes in skeletal muscle that could purge the blood of a substance that accumulated during stress, and was harmful to the brain.

Mia Lindskog, researcher at the Department of Neuroscience at Karolinska Institutet, said that in neurobiological terms, they actually still did not know what depression was and their study represented another piece in the puzzle, since they provided an explanation for the protective biochemical changes induced by physical exercise that prevented the brain from being damaged during stress.

The study showed that protein PGC-1a1 (pronounced PGC-1alpha1) increases in skeletal muscle with exercise, and mediates the beneficial muscle conditioning in connection with physical activity. In this study researchers used a genetically modified mouse with high levels of PGC-1a1 in skeletal muscle that shows many characteristics of well-trained muscles.

The researchers discovered that mice with higher levels of PGC-1a1 in muscle also had higher levels of enzymes called KAT. KATs convert a substance formed during stress (kynurenine) into kynurenic acid, a substance that is not able to pass from the blood to the brain.

Jorge Ruas, principal investigator at the Department of Physiology and Pharmacology, Karolinska Institutet, said that their initial research hypothesis was that trained muscle would produce a substance with beneficial effects on the brain and they actually found the opposite i.e. well-trained muscle produced an enzyme that purges the body of harmful substances.

The study is published in the prestigious journal Cell.