Standard definition: ‘Hydration is the process of replacing water in the body. This can be done through drinking water, and eating foods that have a higher water content’

  • Up to 60% of the human body is water.
  • The brain and heart are composed of 73% water.
  • Your lungs are made up of around 83% water.
  • Muscles and Kidneys are 79% water.
  • Bones are around 31% water.
  • The skin contains 64% water.

H.H Mitchell, Journal of Biological Chemistry


How much?

The European Food Safety Authority (EFSA) – recommends an intake of 2.5 litres of water per day for 2 litres for men and 2 litres for a woman. The recommendations also suggest that you should get 70% - 80% of that from water and the remaining 20% to 30% should come from food.

A 2016 study, by researchers from Monash University in Australia – proved that the 8 glasses a day we’ve all heard don’t apply to everyone, and if just listen to your body, you’ll know when you should drink and when you shouldn’t.

The National Academies of Sciences/Engineering/Medicine – released a study in 2004 that suggested the most people (who took part in the study) met their daily intake (which was individual) by letting thirst be their dictator of when to drink.


Signs of dehydration:

  • Thirst and/or having a dry mouth.
  • Dizzy/ Nauseas/Lightheaded.
  • Lethargic.


These symptoms will be exacerbated during exercise or if you’re in hot climates.

Your core body temperature rises and one of the amazing things your body can do to prevent overheating is to cool you back down by perspiration.

Perspiration is the process of sweating via the sweat glands, which are situated just under the surface of the skin, which cools down your core body temperature.

It goes without saying that if this is in a sporting environment; it is going to affect your performance negatively.

Types of dehydration:

Hypertonic - This is a deficiency in water and leaves the body in a negative fluid balance.

Hypotonic – This is when the salt loss is greater than water loss.

Isotonic – This is an equal of sodium and water. 

How to prevent:

Hypertonic – Follow the recommendations for drinking water, drink when you feel thirsty, and drink more during physical activity.

Apart from illness and disease, which can cause loss of water, most people become dehydrated due to getting caught out without drinking for hours at a time.

Whether its working hours on end or running errands, it is fairly common for people to go hours without consuming any water or eating any food.

My top tip is to simply don’t get caught out. If you can keep a bottle of water in your bag, so if you’re out and about you won’t get caught out.!

Hypotonic – You can ensure you eat foods that contain potassium and sodium.

Isotonic – During exercise water isn’t the only thing that is lost, the body also loses electrolytes, potassium and sodium.

Isotonic drinks are a great way to replenish what is lost during physical activity.

I recommend electrolyte tablets, powders, or sports drinks (low sugar, avoid high-calorie drinks).


Every study I have come across suggest that optimal daily water intake is based on an individual case, hence only recommendations been made. These recommendations will at least leave you within the right ballpark.

As mentioned don’t get caught out, always have water available.

Drink first thing on a morning, you’ve just gone 6-8 hours without any fluids.

Let your body be your guide, and drink when you’re thirsty.

When exercising, drink more water, and even drink isotonic drinks or supplements.

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