Dehydration and Its Effects on Brain Health and Function

The average human body is 60 percent water. Your body uses water to perform a multitude of functions, including: regulating body temperature, lubricating joints, protecting organs, flushing out waste, carrying nutrients and oxygen to the cells and dissolving minerals and nutrients. If you do not replenish your body’s water supply by drinking plenty of fluids and you become dehydrated, your body will be unable to perform its normal functions including attention and memory. Dehydration affects sodium and electrolyte levels in the body, which has also been linked to cognitive changes.

There is limited literature available on how hydration affects human cognitive function, but the brain function is most likely affected by dehydration as well as short-term memory and attention, says Laura DeFina, MD , President and Chief Executive Officer of The Cooper Institute .

It isn’t uncommon to see a marathon runner complete the race, only to receive medical treatment after becoming confused and disoriented. This is caused by a loss of sodium and electrolytes due to dehydration from strenuous exercise and heavy sweating.

“While there is conflicting information, it is pretty clear that hydration affects the brain, particularly in elderly adults and children,” says Dr. DeFina. Elderly adults tend to have more diseases and confounding factors, such as medication that affects hydration. In those who already have cognitive difficulties, when an older adult becomes dehydrated his or her cognitive function becomes even more inhibited.

Disabled adults and young children rely on others to provide water. Thus, their thirst and need for hydration may not be addressed as quickly as it would be for an older child or adult who is able to get a drink on their own when they are thirsty, leading to dehydration.

These brain-related effects of dehydration reinforce the fact that hydration is essential, not just for physical function, but intellectual and mental function.

It is important to keep yourself hydrated, particularly if you live in a hot climate, like Texas. Dr. DeFina suggests these tips to keep hydrated this summer:

• Make an effort to hydrate before exercise, during exercise and after exercise.
• Drink seven to 10 ounces of water every 10 to 15 minutes while exercising.
• Water is the best option, as it doesn’t have unnecessary calories like many sports drinks. Generally, you only need the extra electrolytes in sports drinks after exercising more than an hour.
• Monitor your hydration based on how thirsty you are and the color of your urine. A well-hydrated person has pale yellow urine. Drink when you are thirsty, or if you notice your urine is darker than it should be.
• The recommendation of drinking at least six to eight glasses of water a day is a good rule of thumb, but it is not one size fits all.

Dr. DeFina also pointed out there is no evidence that pickle juice, coconut water or other “trendy” drinks are superior to water.

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