One of the mechanisms by which sport helps fight depression is through the production of lactic acid.
- Lactic acid promotes neurogenesis in the hippocampus, a process that is impaired in depressive patients
- Lactic acid decreases anhedonia, one of the main symptoms of depression, which consists of a loss of interest in activities previously deemed pleasant.
- Lactic acid promotes neurogenesis in the hippocampus, a process that is impaired in depressive patients
Sport is an effective antidepressant. Practicing 35 minutes of physical activity daily reduces the risk of depressive symptoms. The underlying mechanisms are still poorly understood. New work, published on May 27 in the scientific journal Mood Disorders, shed new light. According to the authors, it is lactic acid, or lactate, a molecule produced by the body during physical exertion, which acts directly on the brain and acts as an antidepressant.
A way to bypass antidepressants
The team of Swiss neuroscientists from the National Center of Competence in Research Synapsy have succeeded in demonstrating the antidepressant effect of lactic acid. According to them, this molecule could make it possible to better treat the disease, whether through exercise programs but also by using a molecule with antioxidant properties, derived from lactate metabolism, NAHD. This is the active form of nicotinamide, or vitamin B3, known for its antidepressant effect.
These results are important since, as noted by the study’s lead author, Jean-Luc Martin, “about 30% of people with depression do not respond to antidepressants”. It is therefore essential to find other ways to help these patients as depression affects more than 260 million people worldwide and more than 3 million in France.
Lactate restores neurogenesis
For the study, the researchers gave mice doses of lactate comparable to those produced during physical activity. They found that it helps decrease anhedonia, one of the main symptoms of depression, which is a loss of interest or pleasure in all activities that, before the depression, were considered enjoyable.
In addition, lactate promotes neurogenesis in the hippocampus, an area of the brain involved in memory but also in depression. However, this process, which makes it possible to replace neurons, is altered in depressive patients, which can lead to a reduction in the volume of the hippocampus. By restoring this mechanism, lactic acid reduced depressive behavior in mice.
Researchers must now confirm these results in humans but believe that they offer new avenues for treating depression. “These mechanisms contribute to explaining at least one of the links between sport and its effects against depression, and suggest possible targets for future treatments: playing sports or reviving neurogenesis with an antioxidant molecule such as NADH.”, concluded the researchers.
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