Intensive exercise leads to fatigue of the brain and reduces the quality of human decisions. This conclusion was made by scientists from the Paris medical center Drink-Salpetriere. The results of their research are published in the journal Current Biology.
The center’s specialists found that high physical activity affects the brain like intellectual work, because in both cases the same part of the brain is actively involved. We are talking about the lateral part of the prefrontal cortex, which is responsible for the so-called cognitive control - an immediate reaction to rapidly changing circumstances.
Scientists suggested the idea of such a study at the French National Institute of Sports Expertise and Efficiency (INSEP), where athletes participating in the Olympic Games are trained. INSEP noted that some athletes suffered from the so-called over-training syndrome, in which their athletic performance declined sharply due to a feeling of extreme fatigue. Researchers have wondered if this condition can be explained by brain fatigue, which usually leads to mental work.
To find out, scientists conducted an experiment for which 37 professional male athletes aged about 35 years were selected. Athletes continued their usual workouts, while increasing loads by 40%. Researchers carefully monitored their physical condition, conducted behavioral testing, and did functional brain MRI.
High loads caused severe fatigue among athletes. At this time, they were asked to make a decision on a number of hypothetical business projects. Most participants in the experiment made more impulsive and ill-conceived decisions. For example, long-term projects that promised great benefits, they preferred quick profits.
“The results of our study indicate the fact that the state of the neural brain network plays a significant role: if the brain is tired, then the person has a different approach to making decisions,” said the main author of the study, Matthias Pessiglion.
Scientists explained these results by the fact that cognitive control is required by people both in mental work and in physical work. In the first case, a person constantly analyzes various solutions, and in the second, he calculates whether he has enough strength to perform the exercise, or thinks what to do in unexpected situations.
According to scientists, the data obtained will be useful not only in training athletes, but will also be able to supplement the economic theory of choice, which, as a rule, ignores such changes in the human nervous system. They also believe that monitoring the level of fatigue will help to avoid wrong decisions in the political, judicial and economic sphere.
In the future, researchers hope to find a way to protect the area of the brain responsible for cognitive control from overload.