Is poor hydration worsening your brain fog?

Dehydration can cause symptoms like headache, fatigue, and dizziness. However, a new study indicates hydration status can also affect memory and cognitive function. Could dehydration be contributing to the brain fog of Fibromyalgia and Chronic Fatigue Syndrome? Drinking more water throughout the day may be a simple way to improve symptoms.

A study from as far back as 1980 showed a strong association between dehydration and cognitive function. A recent 2019 study of 2,506 participants (1,271 women & 1,235 men) of age 60 or older were administered cognitive tests and had blood draws to assess hydration status. They determined that those who were underhydrated performed worse on cognitive tests. Interestingly enough, those who were overhydrated also performed poorly on cognitive tasks. The effect was strongest in females.

How much water is enough to optimize cognitive function?

The US Dietary Reference Intake for water is 2.7 liters (91 ounces) for women and 3.7 liters (125 ounces daily) for men. In Europe, the recommendations are a bit more modest. The European Food Safety Authority recommended an adequate Intake (AI) of 2.0 L/day for women and 2.5 L/day for men of all ages.

There is no established upper limit of water intake. However, there is such a thing as too much water! Excessive water intake can lead to life-threatening hyponatremia—a condition where the body is robbed of essential salt. Be wise. A normally functioning kidney can handle more than 0.7 L (24 oz) of fluid per hour but exceeding these amounts is not recommended. With extra water intake, there must also be adequate salt intake.

Proper hydration is essential for MECFS patients

Poor hydration has a direct and dramatic effect on the blood. Because of this, it’s no wonder too little or too much can result in cognitive problems. Dehydration, even moderately so, can reduce blood volume. Low blood volume has long been established in ME/CFS patients and results in common symptoms of the condition such as low blood pressure, weak pulse, rapid heartbeat, and orthostatic intolerance. Underhydration also causes cells to reduce in size. For the red blood cell, this means an impaired oxygen-carrying capacity.

Severe MECFS patients are at high risk of dehydration

Bed rest causes rapid loss of muscle tissue. A topic discussed in great detail in a previous post. Muscle mass is a large storage depot for the body’s water supply-encompassing as much as 70%. As muscle mass is lost through atrophy of bed rest, fluid is rapidly lost as well. The severe, bedridden ME/CFS patient then must ensure adequate fluid intake to counter these losses.

If water intake is difficult due to illness, intravenous or subcutaneous administration of saline can be performed to ensure adequate hydration status. Many patients report benefit from saline administration and it has long been used by ME/CFS physicians.

Older individuals with chronic illness are at risk of dehydration

We come into this world well-hydrated with our bodies made up of nearly 70% water. With age, these water stores rapidly decline to a mere 50%. Combine this with less ability of the kidney to prevent dehydration through buffering. Older individuals have higher fluid requirements. Aristotle once said, ‘old age is dry and cold.’ In several large, long-term studies from the US National Health and Nutrition Examination Survey for example, up to 21-28% of those over the age of 70% were found to be underhydrated. The thirst message from our brain that tells the body to drink is also dampened with age, reducing intake. Those with chronic illness over the age of 60, must ensure extra hydration throughout the day to prevent mild symptoms of dehydration including brain fog, fatigue, and dizziness.

Recommendations

Ensure daily intake of water in divided doses. Don’t rely on thirst cues. Don’t consume a liter in one sitting! Ensure the foods you consume are well-salted. For women, drink at least 2 L per day. For men, at least 2.5 L per day. If over the age of 60, increase these intakes by at least 0.5 L. For severe, bedridden individuals ensure 2.7 L per day for women, and 3.7 L per day for men.  

References

D. G. SEYMOUR, P. J. HENSCHKE, R. D. T. CAPE, A. J. CAMPBELL, ACUTE CONFUSIONAL STATES AND DEMENTIA IN THE ELDERLY: THE ROLE OF DEHYDRATION/VOLUME DEPLETION, PHYSICAL ILLNESS AND AGE, Age and Ageing, Volume 9, Issue 3, August 1980, Pages 137–146.

Bethancourt HJ, Kenney WL, Almeida DM, Rosinger AY. (2019) Cognitive performance in relation to hydration status and water intake among older adults, NHANES 2011-2014. Eur J Nutr.

Hooper, L., Bunn, D., Jimoh, F. O., & Fairweather-Tait, S. J. (2014). Water-loss dehydration and aging. Mechanisms of Ageing and Development, 136-137, 50–58.