Something toxic swells up in your brain after too much exercise: Science warns

A long day at the office can leave you drained and craving TV and a takeaway. But you sit all day. So why do you feel tired like your friends who have physical work?

Struggling through your essential to-do list feels even more daunting when the clock is ticking for home time. Worse still is bumping into a colleague who “just wants a quick minute” out of your way.

It might seem obvious that you’re more likely to make an emotional decision at the end of a long day, but people often do anyway.

A Recent research That scanned people’s brains at various points in their workday and found high-demand tasks that require intense, constant concentration can build up a potentially toxic chemical called glutamate.

Normally used to send signals from nerve cells, large amounts of glutamate alter the performance of a brain region involved in planning and decision-making, the lateral prefrontal cortex (lPFC).

Science has shown once again that mental fatigue has real effects. There are numerous studies that show that court decisions can depend on how tired the judge is.

For example, after a long day in court, Judges are more likely to deny parole (which is considered a safer alternative). Studies show that Physicians are more likely to prescribe Unnecessary antibiotics at the end of exhausting clinical sessions.

New research from the Paris Brain Institute (ICM) investigates whether cognitive functions such as focus, memory, multitasking and problem-solving can cause fatigue in the lPFC, which affects our decisions when crossing things off our list.

opportunity cost

The brain is the command center of the body, controlling circulation, breathing, motor function and the nervous system. The brain coordinates these activities Huge energy consumption costs.

Nerve cells break down nutrients to release energy (metabolism). But this process accumulates by-products known as molecules Metabolism. Glutamate A type of metabolism. The brain clears these toxic waste chemicals in your sleep.

The authors of the Paris study wanted to see if prolonged cognitive tasks deplete the brain’s supply of nutrients. They also tested whether such high-focus demands produce higher concentrations of toxins in the lPFC than in other parts of the brain.

In this case, the authors compared the lPFC to the primary visual cortex, which receives and processes visual information.

To test their hypothesis, the authors divided their 40 participants into two groups. Both groups sat in front of a computer in an office for six and a half hours. One group had to perform difficult tasks that called for their working memory and constant attention.

For example letters were displayed on a computer screen every 1.6 seconds and participants had to sort them into vowels and consonants or, depending on the color of the letters, into upper or lower case letters. The second group did a similar but much simpler task. Both groups managed an average of 80 percent correct response rates.

Scientists used magnetic resonance spectroscopy (MRS) to scan participants’ brains and measure metabolite levels. The authors took readings at the beginning, middle, and end of the day.

They found fatigue markers such as increased glutamate concentrations, but only in the high-demand group. The build-up of toxic chemicals was observed only in the lateral prefrontal cortex [lPFC]) and not the primary visual cortex.

After the high- and low-demand cognitive tasks, the two groups had decision tests. These included choices about physical effort (whether to cycle at different intensities), cognitive effort (whether to perform difficult or easy versions of cognitive control tasks) and endurance (how long they were willing to wait to get one). big prize).

Prizes range from €0.10 to €50 (about US 10¢ to $50). Delays in receiving rewards range from immediate cash after testing or bank transfer after one year.

Rethinking the workday

The authors found that the high-demand group, those with higher levels of metabolism in the lPFC, preferred less taxing choices. These participants had less dilated pupils (dilated pupils suggest excitement) and took less time to make decisions, indicating that they experienced this part of the test as unpredictable.

so Paris study It also raises the question of whether the workday is organized in the best format

According to study results we should break down high-demand cognitive control tasks that require working memory and constant attention and take into account that end-of-day performance takes a hit. Considering these results some occupations may require very different structures.

During their shift, air traffic controllers only guide aircraft for up to two hours, then take a half-hour break. But bus drivers, doctors and pilots would also benefit from regular, mandatory rest.

There are different areas of our brain that are active during different tasks, such as speaking, listening and planning. Therefore, not all of our conclusions can be explained by the results of the Paris study.

Considering interactions throughout the body, a 2006 study The US suggests that new information is best processed in a state of starvation. But hunger makes it difficult to retain newly learned information. Satiety means that neurons are fueled to build circuits Store in long-term memory.

Decisions about third parties, for example a judge passing judgment on a defendant, may be better in a state of satisfaction when tasks involving fine motor function, such as surgery, may be compromised. This is because after a meal, the urge to survive decreases because we don’t have to look for food.

It allows us to judge our environment more objectively. But satiety is a time when the body needs to rest to process food, which is why complex fine motor skills aren’t at their best in this state.

The next time you have to make a tough decision at the end of a long day, be aware that you tend to lean towards low-effort actions with short-term rewards.

If possible, you should sleep on it.

Zoltan MolnarProfessor of Developmental Neuroscience, University of Oxford And Tamas HorvathProfessor of Neurobiology and Ob/Gyn, Yale University

Reprinted from this article the conversation Under Creative Commons license. After this Main article.