Human brain has coping mechanism for dehydration

The human brain can preserve oxygen to protect itself from the effects of dehydration, a new study finds.

Although dehydration significantly reduces blood flow to the brain, researchers in England have found that the brain compensates by increasing the amount of oxygen it extracts from the blood.

"This research has helped us understand a lot more about how the human brain responds to extreme exercise in extreme conditions," study first author Steven Trangmar, a researcher at Brunel University, said in a university news release. "We can now see that blood flow to this vital organ is significantly affected by dehydration. But we can also see that this is when the brain kicks in, preserving its own oxygen consumption to ensure it sustains its function."

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This coping mechanism is likely what enables athletes who become dehydrated during exercise to keep going. The study authors cautioned, however, that their findings should serve as a reminder of the importance of proper hydration, noting that getting enough fluids is essential for athletes who want to maintain peak performance.

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"These findings show that the brain has remarkable ways of protecting itself from extreme circumstances, however they also clearly substantiate the recommendation that people should ingest fluids during exercise to help optimise physiological function and performance," Jose Gonzalez-Alonso, a professor of exercise and cardiovascular physiology at Brunel University, said in the news release.

Read: How exercise affects the brain

In conducting the study, the researchers inserted catheters in the brachial artery and internal jugular vein of 10 experienced male cyclists. Using the catheters and Doppler ultrasound technology, they measured the blood flow of the cyclists as they rode a bike to exhaustion in heat.

As they became dehydrated, the cyclists developed reduced body mass, brain blood flow and ability to exercise, as well as an increase in their internal body temperature.

The findings were published recently in the Journal of Physiology.

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Image: Dehydrated woman from Shutterstock