The surprising way exercise changes the way we make decisions

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Conventional wisdom favors a positive correlation between habitual physical activity and cognitive performance, but perhaps there’s a tipping point. A new study recently published in the journal Current Biolog posits that physical exertion actually alters our ability to make rational decisions.

“Our findings draw attention to the fact that neural states matter: You don’t make the same decisions when your brain is in a fatigued state,” study author Mathias Pessiglione of Hospital de la Pitie-Salpitriere in Pari told WebMD.

The neuronal networks of our brains are particularly susceptible to burnout, effectively revising what we do and don’t consider viable choices.

Neuro-computational impact of physical training

The study began with the recruitment of 37 male endurance athletes. Half of these subjects continued their regimen unchanged (the control group) while others were told to increase the vigor of their training by 40% a session over the course of three weeks.

Both groups were examined via a magnetic resonance image scanner. Using radio waves the researchers were allowed to view important brain structures. A series of tests presented the athletes with decisions that would lead to immediate gratification alongside those that privileged the long view. The athletes that committed to the more rigorous training sessions per week expressed a higher degree of cognitive fatigue, evidenced by reduced prefrontal cortex activity and enhanced choice impulsivity.

The authors wrote, “We suggest a neural mechanism that might underlie the effects of excessive physical training. More specifically, our idea is that training overload induces fatigue in the cognitive control brain system. Cognitive control is needed whenever habitual processes must be monitored, interrupted, and modified so as to better align the behavior to long-term goals. Maintaining physical effort for the sake of fitness, when aversive signals, such as aching muscles, call for stopping, should, therefore, require cognitive control. ”

Psychometric testing revealed that these exerted athletes were driven my immediate rewards as compared to their prudent less exhausted counterparts. The authors have made a point to assert a distinction between cognitive impairment and a modification in decision-making processes. It’s not that the tired athletes suffered any setbacks to cognitive function as a whole they were merely more foolhardy. In fact, other areas of brain function like memory were wholly unaffected.