It’s been a busy day at work and the only break he’s managed is a run to Boots for a fast-eaten meal deal. Ten minutes later and you’re back at your desk responding to emails. At the end of the workday, you’re so exhausted that all you want to do is curl up on the couch until bedtime, perhaps frustrated by your own laziness.
But this feeling of fatigue is not really your fault. It can be explained by science: To deal with prolonged focus without adequate rest, the brain slows down.
According to a new study published in current biology, the brain could be suffering in the same way as the muscles when lactate builds up when you exercise. Prolonged mental activity leads to the accumulation of potentially toxic neurotransmitters.
Glutamate is a neuron that the brain produces to keep you focused on the task at hand. The more you force yourself to focus on tasks throughout the workday, the more glutamate accumulates in the lateral prefrontal cortex.
And, according to researchers at the Paris Brain Institute, there is a clear secondary effect in this overproduction. The brain tries to stop the release of the chemical, which means your decision making gets worse, and then you feel that wave of exhaustion.
“Everyone knows about this feeling, but surprisingly few studies have been done,” says Antonius Wiehler, lead author of the study. Previously, studies have focused on very short periods of concentration rather than something close to a full day’s work.
This study could not have come at a more pertinent time. Since the 2020 lockdown, therapist and psychologist Stephanie Newman says many of us feel unusually tired.
“I have so many clients that are out of stock right now. I don’t think we’ve really processed the trauma of the pandemic that we all went through yet,” she says. “It’s very exhausting to go through a lot of losses without having the ability to step back and take the time to rest and process that. We all had to step up and move on.”
Emma Kavanagh, a psychologist who specializes in the brain’s recovery from trauma, says that in addition to this pandemic fatigue we are also seeing more demanding work cultures. “Now we have jobs that push and push from a psychological standpoint,” she says. But beware if you work a 14-hour day, what you accomplish by the end of that day is “probably not worth the effort that went into it,” says Kavanagh. “I think it’s always worth keeping in mind that when our brains go into this kind of mode, it’s often a sign that you’re not going to be producing good work from here on out.”
How to manage the brain drain
So what, if anything, can be done to stop this seemingly inevitable rut toward mental inactivity?
“If you want to avoid the negative consequences of this [brain drain] on your homework, it’s probably a good idea to do it earlier in the day, particularly things like writing or things that require a lot of thought,” says Antonius Wiehler.
This is largely because sleep reboots the brain, and by morning any glutamate buildup from long periods of concentration is usually gone. Although there is still little research on exactly how or why this happens, Wiehler adds.
But there are other things we can do throughout the day to avoid this daily exhaustion.
For Kavanagh, the key is to allow your mind to go into “default mode” as often as possible. “Default mode is when your brain can daydream, be creative, or just tune out,” he explains.
This default mode allows you to mentally recover from the most stressful “executive mode”. “During busy work days, we use one of the brain networks called the executive control network that controls direct action,” says Kavanagh. With this network, all you have to do is focus; extract knowledge and learn new information.
“It’s very sophisticated but it has a time limit,” he explains. “So when we have that really intense focus, having some time for the default mode network to kick in is a really good way to cleanse our brain to restore balance and prevent glutamate buildup.”
Best way to get into default mode? Queue. “Very few of us take advantage of this time because it’s so boring, but if you avoid filling that line time with scrolling on your phone and just let your mind wander, that’s great for recovery,” says Kavanagh.
Going out in nature for a short walk on a weekday is also very good for the recovery of the mind, but it is better to do it without listening to anything that requires too much concentration.
“The problem with listening to a podcast is that your attention is drawn back to this one thing. But with music, it’s creative, and the network by default loves creativity.” This is also why reading fiction is great for relaxation; allowing the brain to become imaginative.
Still, there are ways to reset that won’t eat up too much of your day if you’re already overwhelmed with work, says Stephanie Newman. “Doing a very quick meditation exercise during the day can really help. I really think all you need is five minutes.”
Newman also recommends walking away from your desk every hour. “But I know this is very difficult now since the pandemic,” he adds. “Everything has changed for a lot of people.”