If you’ve ever worked a long shift at a labor-intensive job or hit the gym a bit too hard without warming up, you are keenly aware of the toll that physical exertion can take on your body.
But what about when you overdo it mentally? There’s plenty of evidence that your mind can sustain similar exhaustion.
It’s not about how much you think
For years, many experts believed that simply taxing your brain’s ability to think was capable of using up glucose that left it depleted and weak, thus making you unable to reliably complete even some basic mental tasks. Subsequent research, however, shows that the amount of glucose used up in this process is negligible and can’t explain the fatigue people frequently feel after particularly tough cognitive exercise.
Instead, a team of French scientists identified an increased presence of glutamate in the brain that seems to correspond with mental exhaustion. Researchers believe that this is the body’s way of sending a signal that it’s time to cool it for a while.
It’s more about how hard you think
The team at Antonius Wiehler of Pitie-Salpetriere University Hospital in Paris reached their conclusion by studying the impact on two sets of test subjects. The first received difficult mental tasks and the second was given much easier problems to solve.
Scientists found that the first group was clearly more fatigued. During one segment of the test, these individuals were more likely to choose a low-exertion, low-reward option while those with easier tasks opted for a higher-cost, higher-payoff alternative.
This research might lead to some breakthroughs in treating a buildup of glucose, but experts say the best way to combat mental fatigue is to rest when you feel exhausted and get plenty of restorative sleep each night.