Exercise may cloud your judgment - study

The study found that oxygen levels in the body are important for maintaining cognitive function during exercise in low-oxygen environments.

Climbing a steep ledge (photo credit: YORAM KRAUS)
Climbing a steep ledge
(photo credit: YORAM KRAUS)

Exercise may negatively affect executive brain activity in low-oxygen environments, researchers at the University of Tsukuba, Japan, found in a new study.

The peer-reviewed study, published this month in Scientific Reports, found that low blood-oxygen levels are one of the main factors that affect executive control-related neural activity and cognitive performance when exercise is performed in low-oxygen conditions.

Executive functions are crucial for complex decision-making and reasoning, effectively controlling and coordinating other brain functions, like memory, emotions and movement, in order to enable more complex behaviors, like learning, planning, judgment and decision-making.

What can be done?

The researchers showed, however, that reductions in such neural activity can be prevented by maintaining proper oxygen levels.

Stroop effect

"When blood oxygen levels remained stable during exercise, the Stroop effect was not as pronounced."

Dr. Genta Ochi, senior author

"When blood oxygen levels remained stable during exercise, the Stroop effect was not as pronounced," senior author Dr. Genta Ochi said.

The Stroop effect is the delay in reaction time between stimuli that are congruent and incongruent – for example, when the name of a color doesn't match the color it is printed in.

"In the brain region of interest—the left dorsolateral prefrontal cortex—there was less of a decrease in activation from the neutral to the incongruent trial," Ochi added.

Regions of the brain with "newer," less critical functions, however, may be of lower priority than those responsible for functions that keep us alive, causing the brain to prioritize the latter over the former when oxygen is in low supply.

Therefore, while physical activities that require judgment and critical thinking are performed in low-oxygen environments, the effects of cognitive fatigue must be taken into account. In some activities, like mountaineering, these capabilities may be the difference between life and death.