14 DAY TRIAL // Having carried out a series of experiments on laboratory mice, researchers believe to have finally figured out how and why going for a run every once in a while helps reduce the risk of developing depression.
As detailed in a recent paper in the journal Cell, it all boils down to how regular physical exercise affects skeletal muscle behavior, and consequently, blood makeup.
The mice experiments
Hoping to gain a better understanding of how regular exercise influences depression risk, researcher Mia Lindskog and colleagues started by creating genetically engineered mice that had high levels of a protein dubbed PGC-1a1 in their muscles.
According to previous investigations, skeletal muscle concentrations of this protein up as a result of regular physical exercise. What this means is that, although never going for a run, these mice had the bodies of well-trained athletes.
Together with other rodents which served as a control group, these genetically engineered mice were then exposed to loud noises and lights that kept flashing. What's more, they were not allowed to sleep and keep active in accordance to their natural circadian rhythm.
Despite the fact that all the rodents that the scientists experimented on were exposed to a stressful environment, the mice in the control group were the only ones to develop depressive behavior after 5 weeks of being constantly toyed with.
The researchers theorize that the genetically engineered mice were kept safe from depression by the excess PGC-1a1 protein in their bodies, which they believe helped clean their blood of a compound that tends to build up during times of stress and that affects the brain. This compound is named kynurenine.
“Our initial research hypothesis was that trained muscle would produce a substance with beneficial effects on the brain. We actually found the opposite: well-trained muscle produces an enzyme that purges the body of harmful substances.”
“So in this context the muscle’s function is reminiscent of that of the kidney or the liver,” researcher Jorge Ruas with the Karolinska Institutet in Sweden commented on the outcome of this series of experiments, as cited by the Alpha Galileo Fountation.
Treating depression in humans
The specialists expect that these findings will pave the way to the development of better treatment options for people diagnosed with stress-induced depression. Still, it's important to keep in mind that science is still a long way from fully understanding this condition.
“It's possible that this work opens up a new pharmacological principle in the treatment of depression, where attempts could be made to influence skeletal muscle function instead of targeting the brain directly. Skeletal muscle appears to have a detoxification effect that, when activated, can protect the brain from insults and related mental illness,” explained Jorge Ruas.