Study: Too Much Exercise Bad for Brain Functions of Athletes

Scientists have found that too much exercise negatively impacts performance and decision-making among endurance athletes. In a study published in Current Biology, researchers from the University College London compared two groups of triathletes who participate in endurance competitions consisting of swimming, bicycling, and distance running. Both groups trained for nine weeks. Those in the experimental group increased their training in each session by 40% for three weeks, while the control group continued their typical nine-week training program. The subjects underwent interviews, physical tests, and brain scans. In one interview, both groups were asked to choose between getting $10 immediately or $50 in six months. Both also underwent a cycling test. Results showed that those in the experimental group were more likely to choose getting the smaller amount of money immediately. Their performance was also inferior to that of the control group in the cycling test. Additionally, brain scans revealed that those in the experimental group had less activity in a region of their brain that aids in cognitive control. Cognitive control helps people endure physical activity in spite of fatigue and helps them avoid instant gratification. This means that decreased cognitive control due to overtraining can cause athletes to perform poorly. Furthermore, it can drain their ability to resist temptation. According to the researchers, the study’s findings show that fatigue should be monitored closely because it can greatly affect how people make decisions. Although the study only involved endurance athletes, the researchers specifically pointed out how important it is to also monitor fatigue among people who make political, judicial, or economic decisions.