The accumulation of toxic substances in the cerebral cortex makes it difficult to perform complex tasks. But the minds of great athletes show that it is possible to overcome very demanding physical tests even when you are exhausted
A particularly difficult task. common experience, but now a study published in the journal Current Biology points to a possible neurobiological explanation for this mental fatigue: theaccumulation of glutamate
in the lateral prefrontal cortex, a very relevant area of the brain since it governs decisions, a sort of brain headquarters. L’accumulation of this substance gives that feeling of increasing difficulty in carrying out complex tasks, so we tend to abandon them in favor of simpler commitments. It is therefore a useful signal to avoid staying on complex tasks when the brain is no longer in a position to cope with them. It remains to understand why the brain needs to limit itself and recover full function. A recovery guaranteed above all by the sleep, which brings glutamate levels back to normal.
When the tired brain shifts to simpler tasks
The study, conducted by a group of French researchers led by Anthony Wiehler, was carried out using magnetic resonance spectroscopy, which identifies the levels of some metabolites in specific anatomical structures. The researchers compared the accumulation of glutamate levels in two groups of people, one engaged in a particularly complex mental task, one in an easier task. They also could verify that when the brain begins to be exhausted it tends to try to move on to easier tasks and to prefer choices that offer immediate satisfaction rather than cognitively more complex choices, based on postponement of satisfaction, which could offer greater benefits. In other words, the brain becomes less capable of more complex and demanding decisions. Considered together with previous studies carried out with functional magnetic resonance, the results of our study support a neurometabolic model in which the accumulation of glutamate triggers a regulatory mechanism that makes the activation of the lateral prefrontal cortex more challenging. . This explains why cognitive control is more difficult to mobilize at the end of a particularly demanding work day.
Overcoming physical fatigue with the mind
But you can read the relationship between physical and mental fatigue also from a different perspective. When undergoing a prolonged physical exertion the sense of tiredness grows: the organism is signaling the need to stop the effort as soon as possible. This feeling has organic basesas the decreased blood glucose and muscle glycogen, where in the meantime lactic acid accumulates, the result of an increasingly less balanced metabolism. These physical signals reach the brain, the place where fatigue is perceived. A feeling that even partially psychological, in fact under intense physical effort the mind tends to recall memories of previous episodes of fatigue and combines physical sensations with the mood of the moment. The psychological component of fatigue contributes to ensuring that no effort limits are reached that could compromise the state of health. The relevance of the psychological contribution to the stressed feeling of tiredness dTimothy Noakes of the Research Unit for Exercise Science and Sports Medicine of the Department of Human Biology at the University of Cape Town. In a study of him, Noakes reports the statements of several record-breaking sportsmen, back in the last century, for which it was absolutely evident that their peculiarity lay in thea mental capacity to sustain effort, like Paavo Nuurmi, Finnish middle distance runner, winner of nine Olympic gold medals and three silver medals in the 1920s, who affirms everything, muscles are pieces of rubber. All that I am, I am because of my mind. A proof of the fact that the feeling of fatigue, at least in part psychological, comes from the extra effort that great athletes can put in at the end of exhausting performances, when they should no longer have energy. Timoty Noakes wonders: How can an athlete accelerate towards the end of the performance, when he should be at his most tired and then slow down? But the mind of the great athlete to make a differencea mind characterized precisely by a particular ability to be able to overcome the barrier of psychological fatigue.
September 24, 2022 (change September 24, 2022 | 13:20)
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