They say that exercise provides energy – but too much can make your brain so tired that it can no longer function.
Researchers discovered that triathletes who gave up their training routine were not only physically worn out, but also had mental fatigue.
Their decision-making power was poorer because scientists discovered that they were less able to think rationally and avoid temptations.
Brain scans showed that they had less activity in the area of the brain that was involved in control, part of the prefrontal cortex, after exertion.
This is because their brains are essentially burned out as a result of the mental effort being made to achieve training goals, scientists say.
Scientists believe that excessive exercise can make your brain tired. Athletes in a study were less able to think rationally and avoid temptations. Stock photo
Dr. co-author Mathias Pessiglione, from Hôpital de la Pitié-Salpêtrière in Paris, said: & You have to control the automatic process that causes you to stop when muscles or joints hurt.
& # 39; The lateral prefrontal region affected by sports training overload was exactly the same as our previous studies had shown to be vulnerable to excessive cognitive work.
& # 39; This brain area therefore appeared as the weakness of the brain network responsible for cognitive control. & # 39;
The original idea for the study came from the National Institute of Sport, Expertise and Performance (INSEP) in France, which trains athletes for the Olympic Games.
Athletes reported suffering from & # 39; overtraining syndrome & # 39 ;, with their physical performance plummeted and feeling overwhelmingly tired.
The team, led by Dr. Bastien Blain, wanted to assess whether the brain was affected by overtraining in the same way as excessive intellectual work.
Athletes have undergone a series of cognitive tests in between cycling exercises (in the photo)
The participants had MRI scans (photo) to assess how their brain activity was influenced by overtraining
SOUND EXERCISE AND A HEALTHY DIET MAY LIFE IN A BRAIN
Scientists have found pieces of evidence that exercise is good for the brain.
Moderate levels – three times a week – and healthy eating can reverse the mental decline of aging by nearly ten years, according to a study at the Duke University Medical Center in the US.
The team found that older people who trained for about 100 minutes a week, combined with a high-whole-grain diet, fruits and vegetables, scored better in planning measurement and organizational skills tests, which can be lost in old age.
The study recruited 160 sedentary people with an average age of 65 who had no dementia but had problems with decision making and planning.
A quarter spent 35 minutes walking, cycling or jogging three times a week for six months while eating a healthy diet.
These people started with an average mental age of 93, determined by a series of testing skills. But after six months their mental age had improved to the level of an 84-year-old.
It is thought that exercise and a healthy diet improve thinking skills by helping the heart work better, thereby increasing blood flow to the brain.
Participants only health advice decreased by six months in three tests of thinking ability.
The study was published in the journal Neurology.
Dr. Blain and colleagues recruited 37 competitive male endurance athletes with an average age of 35.
Participants were instructed either to continue their normal training or to increase that training by 40 percent per session over a three-week period. They were monitored to ensure that they were not training at a harmful level.
The subjective experience of fatigue of the participants was measured using questionnaires every two days.
On & # 39; rest days & # 39; of their training program, participants were subjected to a series of cognitive tests between cycling exercises.
When they got rid of the home trainer, the athletes were asked if they wanted to immediately withdraw a small amount or wait for a larger amount in a hypothetical scenario.
At the same time, the researchers performed MRI scans to assess what happened in the brain.
The study showed that overtrained athletes acted more impulsively and preferred immediate rewards over larger rewards that would take longer to reach.
Brain scans showed that they had shown reduced activity of the lateral prefrontal cortex in making those choices.
The lateral prefrontal cortex is a brain region that plays a crucial role in making decisions and processing rewards.
The findings, published in the journal Current Biology, suggest a link between mental and physical exertion – both require cognitive control.
The authors wrote: & # 39; Cognitive control is needed when usual processes are to be followed, interrupted and adjusted to better align behavior to long-term goals.
& # 39; Maintaining physical exercise for fitness's sake, when aversive signals, such as sore muscles, stop stopping, must therefore require cognitive control. & # 39;
The team warns that although endurance sports – such as running or cycling – are generally good for your health, too many sports can have adverse effects on your brain.
Even poor political, judicial or economic decisions can be prevented by spending cuts, they think.
Dr. Pessiglione said: & # 39; Our findings draw attention to the fact that neural states matter: you don't make the same decisions when your brain is tired. & # 39;
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