Ramallah - "Jerusalem" dot com - Do you find yourself physically exhausted after a long day at work, even if you are just sitting behind a computer table?

Scientists have discovered that there is a reason for this, as a toxic chemical begins to accumulate in the brain after it has been active for long periods of time. So the brain turns toward actions that don't require as much effort to avoid circulating this chemical, glutamate, anymore.

This manifests as a lack of desire to work, or cognitive fatigue, say neuroscientists from Pitié-Salpêtrière University in Paris, France.

Dr Matthias Bisiglione, who led the study, said: “Influential theories suggest that fatigue is a kind of illusion created by the brain to get us to stop what we’re doing and switch to a more satisfying activity. But our findings show that cognitive work leads to real functional change – the accumulation of material. harmful - so fatigue would indeed be a signal to stop us working but with a different purpose: to maintain healthy brain function."

Physical fatigue is a direct result of hard manual work, but thinking hard for a long time instead causes mental exhaustion, causing symptoms such as lack of motivation and ability to focus.

In the study, published in Current Biology, the researchers set out to understand what mental fatigue really is and why it manifests itself.

To do this, they used magnetic resonance spectroscopy (MRS) to monitor brain chemistry over the course of a workday for two groups of study participants.

They divided the group into easy and difficult computer memory tasks that involved remembering and matching a series of letters of different colors for about six and a half hours.

The results showed that people with more difficult tasks tended to choose options that offered smaller rewards for less effort, or those that gave results more quickly.

Next, the scientists studied their glutamate levels at synapses in the brain's prefrontal cortex, and found that they were higher for the group with mentally stressful tasks.

The researchers say this supports their hypothesis that a buildup of glutamate causes the brain to switch to less strenuous actions. This is her way of avoiding cycling or increasing buildup of this toxic chemical, which can impair brain function.

The researchers hope that this finding will provide a new method for detecting severe mental burnout, and informing action agendas to help avoid burnout.

In future studies, they hope to further understand why the prefrontal cortex experiences glutamate accumulation and fatigue after neural activity.

They are also curious to see if the same signs of fatigue in the brain might predict recovery from health conditions, such as depression or cancer.

Source: Daily Mail