(CNN) — After a long day at work, it feels better to leave dirty dishes in the sink or review your finances for later, doesn’t it?
It’s not just laziness. Long-term thinking, making decisions that favor short-term spontaneity but are worse overall, appears to be a biological regulatory tool to combat cognitive fatigue, according to a new study published Thursday in the academic journal Current Biology. it happens.
“Effective theories suggest that fatigue is a type of delusion created by the brain so that we stop what we are doing and engage in more rewarding activity,” said study author Mathias Peciglione, director of Inserm research at the Institute of Brain and Spine. Told. of Paris in a press release. “Our findings suggest that cognitive function causes a true functional change, the accumulation of harmful substances, so fatigue would actually be a signal that causes us to stop working, but with a different purpose: to restore the integrity of brain function. in order to maintain.”
In the study, 40 people were given an easier or harder version of a task that involved separating letters on a screen for more than six hours. According to the study, participants reported their fatigue levels, and researchers used magnetic resonance spectroscopy (MRS) to monitor their metabolic response during the study period.
Each participant was then offered a choice between a smaller, more immediate rewarding reward requiring less cognitive control, or one of more long-term value but involving some impulse control (for example, I’ll give you $10 right now or I will transfer $50 to your bank account tomorrow).
According to the study, the participants who had to think the most during the six hours of the task were more likely to accept the smaller reward. The researchers found that the more the participants thought, the higher their levels of glutamate, a neurotransmitter involved in memory and learning.
The results suggest that when people think deeply for long periods of time, a buildup of glutamate triggers a response in the brain that uses the prefrontal cortex (the area of the brain that allows us to control our thoughts). becomes difficult. According to studies, we make more impulsive decisions than strategic decisions. The less controlled thought you put into your choices after a long day, the less likely it is that glutamate will continue to build up to potentially toxic levels.
If you’re an important decision-maker or trying to prevent tasks from piling up, it’s important not to tire too much, said study author Antonius Wiehler, a cognitive neuroscientist and postdoctoral researcher at the Paris Brain Institute.
But the bad news is that, according to the study, it can also be difficult to accurately measure the degree of fatigue.
take breaks and try new things
To know how to beat cognitive fatigue, you must first recognize when it occurs.
An activity you enjoy is less likely to make you cognitively fatigued, says Philip Ackerman, a professor of psychology at the Georgia Institute of Technology. Ackerman was not involved in the study.
Think about how mentally exhausted you might feel 30 minutes after reading an academic book if you read a novel late at night.
That said, according to Ackerman, if you do something that requires brain power over a long period of time, you’re likely to get tired.
Sometimes you can’t avoid thinking hard for long, and you have to do your best. In those cases, how you deal with cognitive fatigue can make a difference, says Ackerman.
“Feeling tired does not equate to decreased performance,” he said.
People take three responses when they feel exhausted: continue the activity with less effort, focus on working through the stress, or try even harder.
The first option is often correlated with decreased performance, as less attention and effort is put into work without a period of rest to actually recover, he said. The third can be useful for thinking and concentration, but if you have to keep going for too long you run the risk of going downhill.
The second maintains a similar or even higher level of performance during the time spent in focused thought, he said.
Ackerman said people can overcome cognitive fatigue by stopping during difficult thinking.
Those breaks can be restorative for a tired brain if they involve doing a different activity. Even if it’s something that takes effort, changing things up can help rejuvenate a tired mind, he said.
This means that it can be helpful to break up a long day of intense research with a friend to play cards or take a walk in the fresh air. And taking that time off can mean that when you get back to work, you try even better.
And true rest helps too, Pesiglione says.
“I will use the old recipes: rest and sleep! There is strong evidence that glutamate is cleared from synapses during sleep,” he said in the statement.