Excessive Exercise Can Adversely Affect Decision-Making Abilities Of The Brain

The benefits of exercise are widely acknowledged. However, not many are aware of the downsides of overexertion. A new study has found that too much exercise can negatively affect the brain. It can limit the brain’s ability to make decisions.

Researchers said that this type of fatigue is like the one which impacts the neural circuitry after excessive mental effort. Their study found that overtraining syndrome influences the brain as well in addition to the muscles.

Does Overtraining Syndrome Affect The Brain?

Overtraining syndrome is the muscle fatigue that follows intense and excessive physical training. Endurance athletes experience this type of exhaustion when they engage in too much exercise. Scientists of this research work wanted to see if this fatigue arose from the brain’s neural fatigue as well along with muscle tiredness.

They also wanted to know if this effect of overtraining impacted the same area of the brain that too much intellectually demanding work did. For the purpose of the study, researchers brought in 37 participants. These were all male endurance athletes of 35 years of age on average.

Participants either continued with their typical exercise routine or they made each session 40% more intense over 3 weeks’ time. Cycling exercise on rest days and questionnaires that asked about fatigue helped monitor physical activity and its aspects. Then researchers conducted behavioral tests plus MRI scans to analyze participants’ cognitive abilities.

Findings Of The Study

Scientists noticed that physical training overload didn’t only lead to physical fatigue but also behavioral changes. When fatigued athletes gave tests that assessed their economic choices, they acted more impulsively.

MRI scans showed that physical training overload caused an impaired activation of a region of the brain called the lateral prefrontal cortex. This area is that of higher order cognitive control. This means it affects decision-making abilities, planning, motivation, behavior, etc. The impact of this executive control of the brain on motivation is what led participants to seek immediate rewards.

“This brain region, therefore, appeared as the weak spot of the brain network responsible for cognitive control. You need to control the automatic process that makes you stop when muscles or joint hurts,” said Mathias Pessiglione, corresponding author of the study.

What Did The Researchers Say?

Researchers involved in the study said that endurance training is health-benefiting. However, in some cases it may have adverse effects on the brain. Scientists were particularly surprised to notice that physical overtraining affected the same area of the brain that intellectual overload did. This study is the first of its kind, but it had a very small number of participants.

Furthermore, all these participants were fit so it’s unclear whether this effect can be experienced by people at different levels of fitness. Scientists need to carry out bigger experiments to come to solid conclusions.