How Training Too Hard Can Push You to Make Some Really Awful Decisions – runnersworld.com

• According to a new study published in the journal Current Biology, overtraining can affect your decision making skills, leading you to be more impulsive.
• Endurance athletes in the study who drastically increased their training by 40 percent experienced these decision-making problems.
• If you’re following a training plan, stick to what the plan calls for and don’t increase your training any more than what’s recommended.

When you’re training for a race, it’s easy to want to overdo it—the more you run, the better prepared you are, right? It’s actually quite the opposite. Overtraining can lead to things like injury, burnout, and hormonal imbalances. And now, new research out of France shows that it can even mess with your decision making skills.

In the study, published in the journal Current Biology, researchers split 37 competitive triathletes into two groups over nine weeks: normal training and training overload. Those in the normal training group were instructed to continue with the training they were already doing (running, cycling, and swimming). Those in the training overload group, however, had to increase their training by 40 percent over weeks five, six, and seven.

The researchers measured the athletes’ performance on a cycle ergometer they rode on rest days, and they measured the athletes’ fatigue with a questionnaire every two days. Researchers also ran behavioral tests and functional magnetic resonance imaging (fMRI) scans, which measures activity in different areas of the brain.

Their findings? Not only did athletes who were part of the training overload group feel more fatigued overall, but when the researchers’ tests required them to make choices, they acted more impulsively—not thinking about future consequences.

This is due to the part of your brain called the prefrontal cortex, according to Mathias Pessiglione, Ph.D., study coauthor and research director of the Motivation, Brain, and Behavior Lab at Hôpital de la Pitié-Salpêtrière in Paris.

“The prefrontal cortex is involved in cognitive control, a function that helps with suppressing impulses and pursue long-term goals,” he told Runner’s World. “So it is required to continue sport training despite aching joints or muscles. The issue is that it is down regulated, meaning that it is harder to recruit after excessive use. So decision making is biased toward immediate rewards, to the detriment of long-term goals.”

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Along with the decision-making impairment, overtraining also leads to fatigue and decreased power output, the study found—neither of which is helpful to pushing you toward your goals. And even if you’re not training at the level of these triathletes in the study, the same premise applies: Up your mileage gradually, by no more than 10 percent each week, and make sure to follow exactly what your training plan calls for each day. Nope, more is not better.

The good news, though, is symptoms of overtraining will usually go away in a few weeks if you reduce your training load right away, according to Pessiglione.

So if you want to keep your body—and your brain—functioning at their optimal level, keep your training volume on target. Along with zapping your energy and your power, training overload fatigues your brain in a way that is similar to if you were to study for a difficult test.

“It limits prefrontal cortex activity, gives rise to impulsive decisions, and can lead to burnout syndromes,” Pessiglione said.

Associate Health & Fitness Editor Danielle specializes in interpreting and reporting the latest health research and also writes and edits in-depth service pieces about fitness, training, and nutrition.