Too much physical exertion appears to make the brain tired.
That’s the conclusion of a study of triathletes published Thursday in the journal Current Biology.
Researchers found that after several weeks of overtraining, athletes became more likely to choose immediate gratification over long-term rewards. At the same time, brain scans showed the athletes had decreased activity in an area of the brain involved in decision-making.
The finding could explain why some elite athletes see their performance decline when they work out too much — a phenomenon known as overtraining syndrome…
…The brain appears to be constantly reassessing the value of a goal, says Todd Braver, a professor of psychological and brain sciences at Washington University in St. Louis.
“So your brain is doing these kind of cost-benefit trade-offs all the time,” he says. “Is it still worth the effort? Is it still worth the effort?”
And the answer to that question may change as the body’s level of fatigue increases. “The brain might have this kind of built-in mechanism to say, ‘Hey, it’s time to shift from this goal to another one,’ ” he says.
For an athlete, Braver says, that could mean abandoning the goal of winning a race and embracing a goal that will let them recover.