How exercise can improve mental health
In mice, exercise increases the amount of a protein in the brain that reduces anxiety and depression.
Exercise is not only good for our physical health but it benefits our mental health and abilities too. Physical exercise can affect how much of certain proteins are made in the brain. In particular, the levels of a protein called brain derived neurotrophic factor (or BDNF for short) increase after exercise. BDNF has already been shown to enhance mental abilities at the same time as acting against anxiety and depression in mice, and might act in a similar way in humans. Nevertheless, it is currently not clear how exercise increases the production of BDNF by cells in the brain.
Sama Sleiman and co-workers have now investigated this question by comparing mice that were allowed to use a running wheel for 30 days with control mice that did not exercise. The comparison showed that the exercising mice had higher levels of BDNF in their brains than the control mice, which confirms the results of previous studies. Next, biochemical experiments showed that this change occurred when enzymes known as histone deacetylases stopped inhibiting the production of BDNF. Therefore Sleiman and colleagues hypothesised that exercise might produce a chemical that itself inhibits the histone deacetylases.
Indeed, the exercising mice produced more of a molecule called β-hydroxybutyrate in their livers, which travels through the blood into the brain where it could inhibit histone deacetylases. Further experiments showed that injecting β-hydroxybutyrate directly into the brains of mice led to increase in BDNF.
These new findings reveal with molecular detail one way in which exercise can affect the expression of proteins in the brain. This new understanding may provide ideas for new therapies to treat psychiatric diseases, such as depression, and neurodegenerative disorders, such as Alzheimer’s disease.
To find out more
Read the eLife research paper on which this eLife digest is based: “Exercise promotes the expression of brain derived neurotrophic factor (BDNF) through the action of the ketone body β-hydroxybutyrate” (June 2, 2016).
