How Drinking Water Affects Brain Function

by Paul McTaggart

What if I told you that maintaining optimum brain function doesn't need to be complex or complicated?

It's really simple, you know. Your brain is made up of somewhere between 70-80% water and every single act that your body performs is dependent on it; organ function, blood flow, nervous system and brain function, of course. Maintaining optimum brain function then, can be as simple as staying hydrated.

But just how intrinsic is the relationship between water and brain function?

The Statistics

Studies show that just a 1% loss in body water is likely to lead to a 5% decrease in cognitive function. After that sort of dip in body water, dehydration is underway bringing with it a range of other factors. This drop in cognitive function can also mean lack of focus, dip in thinking speed and impact on your mood.

A 2% loss in body water can lead to fuzzy short-term memory, more problems focusing and trouble with math calculations - as if we needed more trouble with those! Having said that, a 2% loss in body water is pretty substantial and would only result from a period of 4-8 hours without any water.

The Implications

Combined with those affects, your brain has to use significantly more energy to complete tasks under the strain of dehydration. A study by King's College London found that when comparing two groups of teenagers, a dehydrated group experienced stronger than usual activity in the frontal-parietal section of their brains than an adequately hydrated group. Despite this heightened activity the dehydrated group did not perform the problem solving task given any better than the hydrated group who didn't see an increase in energy expenditure in that part of their brains.

How to Avoid Them

The only way to avoid the negative consequences of dehydration on cognitive function is to stay hydrated. A study carried out by the University of East London showed that drinking just one glass of water can speed up thinking by 14%. The study was carried out on 34 men and women who completed a number of mental tests twice – once after a breakfast of just a cereal bar and again after a cereal bar washed down with a glass of water. The group were able to think 14% quicker in the second test after drinking the water.

Try getting ahead with hydration by drinking a 1L of water in the morning before your busy day kicks off. This will give you the best chance of staving off dehydration throughout the day, meaning that you can keep your brain functioning at the highest possible level.