Can chronic dehydration cause the brain to shrink? 

Our brains are more than 80% water. When we fail to replace the fluids lost through sweat, our bodies can borrow water from cells in the brain to perform basic and essential processes in our bodies. This causes brain cells to die and shrink.

As the brain shrinks, it moves away from the skull, exerting stress, which causes the headache associated with dehydration.

But how much exactly does the brain shrink?

A team of UK researchers found that 90 minutes of sweating without replenishing lost fluids shrinks the brain by as much as a year of ageing. It also causes cell death the same as during two and a half months of Alzheimer's disease.

The same study showed that dehydration not only affects the size of the brain, but also how efficiently it works.
With just a 1.1% weight loss (about 1.1 % dehydration), the researchers observed increased neural effort when performing basic cognitive functions, affecting short-term memory, long-term memory, arithmetic and overall problem solving.

The good news is that these effects can be easily reversed by re-hydrating with adequate fluids.

The bad news is that proper hydration is not always easy or possible. Research suggests that we often drink enough fluids to replace those that are lost each day and that many of us walk around in a perpetual state of dehydration.

In adults, chronic dehydration not only impairs cognitive function, but can lead to many other serious problems, including constant headaches, fatigue, weight gain, digestive problems, kidney stones, depression and bladder, prostate or kidney cancer.

Chronic dehydration - how to prevent it?

Don't rely on thirst alone to determine fluid requirements. On average, the thirst response does not start until dehydration increases to 2%. Continuous dehydration can cause a loss of sensitivity to water deficiency, so the thirst response is even more delayed. By the time you 'feel compelled' to drink, the adverse effects of dehydration may already be present.

Instead, take a proactive approach to fluid intake. Aim to drink around 180-250ml of water every hour over an eight-hour working period. During hot weather, heavy physical work or exercise, this amount should be increased. The American Conference of Governmental Industrial Hygienists (ACGIH) recommends that workers consume 250 ml of water every 20 minutes when working in hot conditions. However, these are only recommendations and actual fluid requirements vary depending on our body characteristics, activity level, fitness level and environmental conditions.

For best results, focus on drinking small amounts frequently throughout your working day. Do not try to make up large amounts of fluid in one go. Your body can only absorb a small amount of water at a time, and excess water is held in the stomach, making you feel bloated and unwell.

Finally, don't forget your electrolytes. When we sweat, we not only lose water, but also essential salts known as electrolytes. Electrolytes play a key role in maintaining proper water levels in the body. So if they aren't replenished, absorbing and maintaining proper fluid levels will be difficult. To replenish electrolytes quickly, add an effervescent HID-RATION™ tablet to your water, which you should always have with you when you are working hard or training.