One of the mechanisms by which exercise helps against depression is the production of lactic acid according to a new study.
Exercise is an effective antidepressant. Daily 35 minutes of exercise reduces the risk of depressive symptoms. The underlying mechanisms are still poorly understood. New research published in Nature Molecular Psychiatry sheds new light on this issue. According to the authors, lactic acid, or lactate, is a molecule produced by the body during physical activity that acts directly on the brain and plays the role of an antidepressant.
A way to bypass antidepressants
The team of Swiss neuroscientists from the National Center of Competence in Research Synapsy has succeeded in demonstrating the antidepressant effect of lactic acid. According to them, this molecule could allow better treatment of the disease, either through exercise programs or by using a molecule with antioxidant properties derived from lactate metabolism, NADH. This is the active form of nicotinamide, or vitamin B3, which is known for its antidepressant effects.
These findings are important because, as the study’s lead author Jean-Luc Martin notes, “about 30% of people suffering from depression don’t respond to antidepressants.” It is therefore important to find other ways to help these patients, as depression affects more than 260 million people worldwide.
Lactate restores neurogenesis
For the study, the researchers administered doses of lactate to the mice similar to those produced during physical activity. They found that this reduced anhedonia, one of the main symptoms of depression, which consists of a loss of interest or pleasure in any activity that was considered pleasurable before the depression.
In addition, lactate promotes neurogenesis in the hippocampus, an area of the brain involved in memory, but also in depression. However, this process, which allows the replacement of neurons, is disturbed in depressed patients, leading to a decrease in the volume of the hippocampus. By restoring this mechanism, lactic acid reduced depressive behavior in mice.
The researchers now need to confirm these findings in humans which they believe will open new avenues for treating depression. “These mechanisms help explain at least one of the links between exercise and its effects on depression and suggest possible targets for future treatments. Exercise or stimulating neurogenesis with an antioxidant molecule such as NADH,” the researchers concluded.