Thinking for several hours can lead to a feeling of mental exhaustion

BET À DAY

A big day of mental work seems as exhausting to you as a big sports training session? It's not just an impression, since thinking for several hours can cause a feeling of mental exhaustion, revealed a recent study.

While computers can work non-stop, the human brain cannot. The researchers' goal was therefore to understand what mental fatigue really is.

According to the results of the study published Thursday in the journal “Current Biology”, thinking intensely for several hours releases a toxin reaching the prefrontal cortex. Thus, this toxin comes to reduce the control of the decisions taken by the person who favors actions of least effort as fatigue progresses.

Although influential theories suggest that fatigue is a “illusion concocted by the brain” directing us towards rewarding activities, cognitive work would lead to a “real functional alteration”, explained, by way of press release, Mathias Pessiglione, professor at the Pitié-Salpêtrière University in Paris and co-author of the study.

“Fatigue is indeed a signal that makes us stop working, but for another purpose: to preserve the integrity of brain function,” he added.

The researchers thus noticed signs of fatigue during more difficult mental work in addition to having a higher level of glutamate. Thus, the only way to recover from mental exertion is to rest.

“There is good evidence that glutamate is cleared from synapses during sleep,” Pessiglione said.