BRAIN. 65% of French practice a sport at least once a week to get in shape, to excel, to lose weight, build muscle or release stress. Today, an additional incentive is added to the list. Physical exercise also transforms the brain! As proof, the results of a Finnish study published by the University of Jyväskylä in March. Ten pairs of adult male twins, aged 32-36 years, the twins who made the more physical activity during the previous three years has a larger volume of gray matter (cell bodies and synapses) in two brain structures crucial, striatum (involved in voluntary movement and pain management) and prefrontal cortex (the "CEO" of the brain).
Long before this discovery, it was already known that sport had an impact on our head. All those who exercise have already felt. After a workout, though tired, you feel relaxed and in a better mood. "The beneficial effect is immediate, it is called acute effects," said Professor Charles Yannick Guezennec, former professor at the Val de Grace hospital, sports doctor at the hospital in Perpignan, whose research focused on endocrinology and neurochemistry of fatigue among top athletes. But there's more: "When the drive is smooth, another effect, chronic one, moved, leading to a comprehensive and lasting improvement in our mind."
Less anxiety, less depressed and neuroses
A large study from the Free University of Amsterdam (Netherlands), dating back to 2006, was already very illuminating on this point. 19.288.sujets, from adolescence to adulthood, were followed for eleven years. As a result, those who practiced at least 60 minutes of exercise per week on average were less anxious, less depressed, less neurotic, more extroverted and sought more intense sensations than non-practitioners. "It is a proven fact, muscle activity affects brain neurochemistry and probably therefore the behavior," says the specialist. The head and legs are well linked by some secret mechanism. Yes but which one?
The first hypothesis dates back to 1980, after the observation of the antidepressant effect of running. It then assigns the phenomenon to an increase in blood levels of endorphins, neurotransmitters endogenous opioid analgesic and euphoric properties. One even wonders if some athletes would not become addicted to this natural morphine! In 2008, a brain imaging study at the University of Munich (Germany) shows ten athletes in some brain areas well set opioids during exercise. But this theory accuses weaknesses.
"When you administer an antagonist of endorphins, naloxone, we do not change the behavior of the athlete," said Charles Yannick Guezennec. So there would be other processes at Firstly, secretion. - During physical activity - monoamines (epinephrine, norepinephrine, dopamine) and cortisol (the stress hormone), which generate a General stimulation and euphoria. Today another hypothesis is favored, the so-called "serotonergic axis explains the doctor. Muscle contraction give rise, after some time, an influx of amino acids (tryptophan) which promote the synthesis of serotonin in the brain, a neuromodulator involved in many functions including regulation of mood. "
The anti-depressant effect of sport.
Prolonged muscular activity causes a release of tryptophan (amino acid) by the muscle (1) and liver (2). Crossing the blood-brain barrier, which protects the brain, tryptophan will promote the synthesis of serotonin (3), essential in the regulation of mood, anxiety, appetite and sleep.
More subjects were exercising, the better their memory
Through the combination of these mechanisms, athlete exercise plays a stimulating role, antidepressant and painkiller. But not only. Studies show that it also improves memory. In 2003, the team of Marcus Richards of University College London (United Kingdom), examines the relationship between physical activity and memory in adults in 1919. Their activity level is measured at the age of 36 years and their verbal memory 43 and 53 years. Conclusion: most subjects did exercise at 36, the better their memory in middle age! The effect can be more immediate.
In 2014, Lisa Weinberg of the team at the Georgia Institute of Technology (USA) asked students to memorize 90 pictures and then practice a resistance exercise legs - while a control group sat. Two days later, students had to recognize the greatest possible images on a batch of 180. Surprise, the trained group was able to recognize 60%, 10% more than the control ...
Sport he has an impact on school performance? "Yes!" Says Martine Duclos, chief of medicine service of sport at the Clermont-Ferrand Hospital. The researcher, who is currently analyzing the future of 13,000 French adolescents 15 to 19 years, found "a positive correlation between their physical condition and the high school category in which they were (general, professional, agricultural)." In 2013, a study by the University of Dundee in Scotland that followed 4755 adolescents 11, 13 and 16 years already showed that the level of moderate physical activity had a positive impact on performance in English, mathematics and science.
"We must rehabilitate the muscle", asserts Martine Duclos. And the doctor to discuss a phenomenon of direct action on neurons, at least in mice, "Muscle activity results in the production of myokines, proteins which, through a complex mechanism will push the brain to produce factors growth, and more particularly neurotrophins BDNF (brain-derived neurotrophic factor). " In mice, BDNF is involved in the formation of neural circuits and as important regulator of synaptic plasticity. It promotes the creation of microvessels (angiogenesis) and production of new neurons (neurogenesis).
30 minutes of activity per day for an adult
"In summary more muscle activity, the higher angiogenesis and neurogenesis are important, the greater the synaptic connections and therefore better cognitive abilities," explains Martine Duclos. Still to prove the humans. And many questions remain unresolved: the beneficial effect stops there when the drive stops? What level of physical activity to locate in making the most?
In the absence of specific tests, specialists cite official recommendations for general health: an hour a day of moderate to vigorous activity for children, 30 minutes of moderate activity five times a week for an adult or a teenager. More hesitation for the welfare of our head, our slippers sneakers.
