Exercise has many physical, psychological and social benefits. In addition to strengthening the immune system and preventing certain diseases, it improves mood, self-esteem and physical appearance, considering this from a physiological point of view, it is beneficial for cardiovascular and respiratory health, but the brain also benefits during physical activity.
Exercise modulates the release of neurotransmitters, the chemical cells responsible for communication between neurons, on the other hand, intervenes in neurogenesis, a process by which new neurons are regenerated and created, promoting brain health and good cognitive functioning.
These processes will be detailed below
Traditionally it was thought that aging and certain habits led to neuronal death, however, a few years ago, science proved that this was not the case.
It has been observed that neurons can be repaired, find compensatory mechanisms and increase the efficiency of the networks that form them; this ability is called brain plasticity and is critical to the development, learning and recovery of different injuries.
Within brain plasticity, in the context of how the brain changes when we exercise, one of the main mechanisms is neurogenesis. The creation of new neurons is not a process that occurs in all areas of the brain. The hippocampus, olfactory bulb and the subventricular area of the lateral ventricle are the areas in which this phenomenon occurs.
Over the past decade, researchers have focused their efforts on determining the factors that promote neurogenesis and those that prevent it, so they saw that it is favored by an enriched environment and physical exercise.
It is not entirely clear how exercise affects neurogenesis, however, there is sufficient evidence that BDNF and VEGF levels increase after exercise.
BDNF, or brain-derived neurotrophic factor, and VEGF, a vascular endothelial growth factor, are proteins that promote neuron survival and blood vessel formation, respectively.
It has been observed that BDNF increases from 2 to 3 times in our brain during physical activity and that its levels are restored approximately one hour later, the increase of this protein is linked to a 2% annual increase in the volume of the hippocampus, which decreases from 1 to 2% due to age.
In short, exercise increases the expression of NMDA receptors in hippocampus neurons, activating these receptors increases calcium levels in the synapse, in turn causing the activation of certain pathways that regulate the expression of BDNF proteins.
BDNF, in turn, activates another receptor (TrkB) that is very present in cells that give birth to the hippocampus, favoring the creation of new neurons.
Although the mechanism that links VEGF to neurogenesis is not clear, it has been related to neurogenesis both directly, generating changes in the cells that give birth to neurons, and indirectly increasing the number and circumference of blood vessels.
The increase of blood vessels and their perimeter promotes better circulation and therefore cellular health, so in the context of brain evolution during exercise an increase in progenitor cells and a reduction in cell death were observed, modulating the expression of macrophages (immune system cells that eliminate foreign substances).
Physical exercise causes an increase in levels of various neurotransmitters, for example, there is an increase in catecholamines, catecholamines are neurohormones that prepare the body to respond to situations of stress, threat or physical activity.
In this group there are norepinephrine, dopamine and adrenaline, the increase of these substances and endorphins is responsible that when we exercise we feel more active and increase our well-being.
There is also a decrease in cortisol, which reduces stress and therefore reduces the harmful effect of this hormone on neurons.
The process of neurogenesis and, in general, neuroprotection, occurs mainly in the hippocampus, a region of the brain specialized in spatial learning and short- and long-term memory consolidation.
Thus, in the context of how the brain changes during physical activity, it has been observed in several studies that regular exercise improves learning and memory.
In addition, it seems that this effect, also due to improved mood and reduced stress, extends to other cognitive abilities, such as processing speed, decision-making and selective attention, all of which ultimately links physical exercise to an improvement in overall cognitive performance.