Unfortunately, as we age, the brain slowly changes. In particular, some structures such as the hippocampus involved in memorization and spatial navigation lose gray matter (neurons). Brain imaging studies are relentless: the hippocampal volume is reduced by 2 to 3% per decade, then by 1% per year from 70 years …
But, good news, it is precisely in this area that we have discovered the production of new neurons (neurogenesis), throughout life. And we now know how to promote this phenomenon. One of the methods is physical exercise. “Many studies have shown that physical activity stimulates the formation of new neurons,” explains Pierre-Marie Lledo, professor at the Institut Pasteur, the French specialist in neurogenesis.
By contracting, the muscles release particular proteins (myokines). Via the bloodstream, they will activate the release in the brain of nutritive (trophic) factors such as brain-derived neurotrophic factor (BDNF), which stimulates the proliferation of baby neurons and increases their survival. In the short term, physical activity also changes the body’s metabolism: the respiratory and cardiac rhythm increases, improving blood flow to the brain. Result: Stem cell niches located near richly vascularized areas are more active. In the long term, physical activity also increases the size and number of micro-vessels in the brain. This brings more nutrients and oxygen especially to stem cells.
Notger Müller’s team undertook to compare the effects of dance and aerobic sports on the structure of the brain
So do sports, makeover for neurons! Yes but which one? “To obtain this benefit, physical activity must be aerobic, that is to say, a sustained exercise of long duration (more than twenty minutes) causing a rise in the heart and respiratory rate (cycling, jogging, swimming …). “, Replies Pierre-Marie Lledo.
What if another form of sport was so beneficial? This is the question that the University of Madebourg asked itself. Notger Müller’s team has thus undertaken to compare the effects of dance (which involves, in addition to physical exercise, multisensory aspects) to those of aerobic sports, on the structure of the brain.
52 healthy people aged 63 to 80 years were divided into two groups. For 6 months, they received two weekly classes of 90 minutes, either of classic fitness (endurance, stretching …) or dance, then one session per week for 12 months. The content of the dance course included the learning of many different choreographies, with different steps taken from chachacha, mambo … and many positions of balance.
The volume of the hippocampus was measured by magnetic resonance imaging before, after and under study. Observation: both groups see the increase in the volume of the hippocampus, especially in the substructures of the left hippocampus. But in the group “dance” one notes the increase of two zones in addition, the toothed girus (where the new neurons are produced) and in the subiculum. In addition, other tests revealed that the group of dancers ultimately had better scores on the balance tests.
“This indicates that, aside from physical training, the other factors inherent in the dance contribute to changes in the volume of the hippocampus too,” say the authors, who conclude: “therefore, dance is a promising candidate to counter age-related decline in physical and mental abilities. “