It’s the weekend and you feel very tired? Whether this fatigue is physical or mental, several mechanisms can explain it.
- Fatigue is a feeling of physical or cognitive weakening that can occur following muscular efforts (in the case of physical and/or sporting activity) or cognitive efforts (during intellectual or mental work), resulting in difficulty in continue the effort.
- According to the National Institute of Sleep and Vigilance (INSV), 29% of French people sleep less than 7 hours a day on weekdays.
There is fatigue and fatigue… Indeed, under this word suitcase hides several realities. On the one hand, physical fatigue, which when it responds to an effort and remains temporary and reversible contributes to the progression of our performance, explains Professor Stéphane Perrey Director of the EuroMov Digital Health in Motion Research Unit at the University of Montpellier, in an article published by The Conversation. On the other hand, mental (cognitive) fatigue which refers to “an experienced psychobiological state […] after performing an intense and/or prolonged cognitive task, which is characterized by a feeling of exhaustion and lack of energy“.
The brain indicates if you are too tired
However, physical fatigue is not only muscular and mental fatigue is not only psychological and the two fatigues interact more than we think, reminds the expert: “As a mental or physical task is prolonged, fatigue appears and results in adaptations in the activity of our brain. We observe in particular that the prefrontal cortex, the “control tower” particularly involved in our emotions and mood disorders, our working memory, our decision-making, our motivations and our concentration, will modulate its activity.
In both cases, it is the brain, as a good strategist, which indicates when we are too tired or that we must continue to make reasonable efforts. Indeed, to tolerate the unpleasant signals sent in particular by our muscles such as pain, we depend on the prefrontal cortex which is capable of inhibiting other brain structures such as the anterior cingulate cortex (involved in the regulation of decision-making, empathy…), the amygdala (response to fear…) and the insula (the consciousness, emotions, etc.).
Fatigue impacts decision making
Regarding mental fatigue after intense and prolonged intellectual effort, recent research showed that metabolic changes in the brain could be the cause. A significant mental effort indeed causes the accumulation of a by-product of the activity of neurons, glutamate which can become harmful when there is too much: “Its accumulation in certain areas of the prefrontal cortex alters the functioning of this key region: which simultaneously disrupts reasoning and decision-making, so that we make more impulsive rather than strategic choices..”
Thus, it is useful to know how to get tired without exhausting your resources and to know the signs of recurrent and harmful fatigue for the body to avoid overwork or burn-out. In case of diminished attention span, increased anxiety and a decline in motivation and working memory, it is good to sleep or get help from health professionals if sleep does not work. not enough to recover.
