Oxygen deficit, otherwise known as hypoxia, in the brain is a matter of emergency that can permanently damage nerve cells. However, growing evidence suggests that hypoxia can also be a vital signal for growth. According to a recent study, activities, that are mentally and physically demanding, triggers a local, as well as, a brain-wide “functional hypoxia”. It has similar effects to oxygen deprivation.
From Deficit to Growth
Along with other things, the shortage of oxygen activates the growth factor erythropoietin (Epo), responsible for stimulating the formation of new synapses and nerve cells. This mechanism might be able to explain why mental and physical training has a positive effect on mental performance into old age.
About the Study… and the Mice
The study was initially conducted on mice. The researchers let them run on a specially prepared running wheel for days to challenge them both mentally and physically. Absolute attention was necessary for the mice to avoid stumbling on the wheel, in addition to being physically exhausted. Two comparator groups were created – one where the mice had no access to a running wheel and another where the mice were exposed to oxygen-depleted air. The researchers were also keen on finding the brain’s reaction to activity-induced hypoxia.
The training had effects that were quite similar to reducing the oxygen content of the air we breathe. In both cases, similar changes in the activity of multiple genes were noted while a mild oxygen deficit occurred throughout the brain. However, the differences between various cell types were major – nerve cells were the ones that were affected as compared to glial cells (auxiliary cells of the neurons), which were affected slightly. However, researchers were astonished to find that the Epo gene in the brain, along with several other genes, was predominantly stimulated during mental and physical activity.
How We can Benefit
The researchers are trying to take the study to the next level to find if the same theory applies to a human being. They are willing to conduct similar studies on humans who are active on exercise bikes. The results, if positive, could offer massive benefit to patients with neurodegenerative diseases, where nerve cells either lose synapses or die.