Just add water ….

Why is hydration so important?

Around 60 – 70% of the human body is composed of water.

Breaking that figure down further… approximately 95% of the brain, 90% of the lungs, 83% of the blood, 76% of the muscles and 22% of the bones are composed of water! It goes without saying that many essential bodily functions are dependent upon water.

These facts are often forgotten, or overlooked day to day, which makes people more susceptible to chronic dehydration. Water is more than just a zero calorie, free (to most people) fluid that is an option to sip on throughout the day.

Consider the following;

• The blood (mainly composed of water) supplies cells in the body with oxygen and nutrients and carries waste out of the body.

• Water is responsible for regulating body temperature. Sweating is the body’s function to cool down internal temperature.

• Water lubricates joints.

• Water cushions vital organs.

How can you tell if you are dehydrated?

Common symptoms of dehydration, include;

• Thirst

• Headache

• Lightheadedness / low blood pressure

• Going to the bathroom less frequently

• Urine colour – Dark yellow / orange / brown colour*                                                                      (pale yellow = adequate hydration*)* Vitamin C supplementation can result in bright yellow urine despite adequate hydration.

What can dehydration lead to?

• Heat exhaustion

• Tiredness / confusion

• Reduced physical performance

• Reduced concentration / inability to focus

• Urinary Tract Infections

• Kidney stones

• Renal failure

How can you avoid dehydration?

As little as 2% dehydration can impact upon mental and physical performance. The most effective way to avoid the onset of dehydration is to sip fluids regularly throughout the day, rather than waiting to experience symptoms of dehydration.

It is important to be aware how much fluid you need on a daily basis. As a general guide, 30 millilitres (ml) per kilogram (kg) bodyweight provides an adequate level of hydration, relative to a persons size (and water content). Things that will affect this, include; environmental temperature and humidity and also physical activity level. Obviously, as the environmental temperature increases, or as physical exertion increases, so does the body’s fluid demands due to water lost through sweat.

During exercise, the following is recommended;

approximately 125 – 250ml  every 15 – 30 mins (nutrition.org.uk)

The most reliable way of telling how much fluid has been lost during exercise / competition is to weigh yourself before and after. 1 kg weight loss is equivalent to 1000 ml fluid loss. You need to consume 1.5 times the fluid loss to account for fluid lost via urine.

Whilst working in extreme heat, the following is recommended;

approximately 200 – 250 ml every 15 – 20 mins (CDC, USA)

Do not drink more than 1400 ml within 60 mins. Overloading can cause a medical emergency as the concentration of salt in the blood becomes too low. Drinking little and often is more effective and safer than drinking large amounts of fluid in a short period of time.

Which fluids should you consume?

Aside from water, plenty of other fluids will provide effective means of hydration including; diluted cordial, fruit juices, milk, isotonic sports drinks etc. Obviously, water is a great choice due to the lack of additives and sugar. However, opting for fluids that you like the taste of is proven to increase fluid intake. It is important to be aware of the nutritional content of fluids and ensure they fit with your dietary goals. It is also important to note that both caffeinated and alcoholic drinks lead to increased urine output and contribute to dehydration, which should be factored in when considering your daily fluid intake.

When exercising over a couple of hours it is important to replace electrolytes lost via sweat. Water is fine to drink providing salts are replaced through foods. The other option is to consume sports drinks during long bouts of exercise, although excessive consumption can significantly increase caloric intake and also lead to gastro-intestinal problems.

If in doubt, sip water regularly throughout the day and check the colour of your wee!