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Did you know that when you feel thirsty, you are already dehydrated? 1,2 Drinking water is the best way to keep you hydrated throughout the day and the body functioning well. When you lose excessive water and electrolytes through illness such as diarrhoea, it is critical to replace the right combination of ingredients for your body to absorb everything it needs to function correctly. 2,3
Normal water loss vs dehydration
Every day you experience situations which can lead to water loss.  Breathing, sweating, urinating, vomiting and diarrhoea can lead to your body losing more water or electrolytes than you are taking in. 1  A healthy person’s body is made up of between 45 % and 75 % water by weight. That is roughly 42kg in a 70-kg man and about 26kg in a 50-kg woman. A newborn baby’s body comprises 75 % water, which lowers to about 60 % by six months. Our bodies control their water volumes very tightly, which generally fluctuates at less than 1 % per day for adults. In other words, around 250 ml per day for women and 500 ml per day for men. 2
Infographic showing the water content of humans

When you have a fever during illness, the body heats up and needs to cool itself down by sweating. Perspiration consists of water and several vital salts (electrolytes) like sodium, potassium and chloride. 4 Someone who has diarrhoea loses electrolytes such as sodium, chloride, potassium and bicarbonate. They can also lose up to 200 ml of fluid per kilogram of body weight in 24 hours. That could be more than 12 litres in one day for a person weighing 60 kg! When someone does not adequately replace this fluid loss, they could dehydrate. 1

Recognising the signs of dehydration

How do you know if you or your child is dehydrated? In the early stages of dehydration, generally, the person will experience no signs or symptoms. As dehydration increases,  they may experience some symptoms. 1

Table showing the signs of dehydration

When someone shows signs of severe dehydration, it is best to get them to a medical facility as soon as possible, as they will need to be treated intravenously (directly into the vein with a drip). 1

You may need more than water as a dehydration treatment due to diarrhoea

Drinking enough water during the day is very important to prevent dehydration, whether you are well or during an illness such as diarrhoea. So why is drinking only plain water not enough to treat dehydration during a bout of diarrhoea? 1,2


When a person suffers from diarrhoea, it damages or irritates the intestines. Consequently, they do not absorb nutrients (specifically sodium) or water from the liquids or foods we drink or eat as they are supposed to. If we cannot absorb sodium, we can also not absorb water, and dehydration can worsen. 3


So how do we get to absorb the sodium?

Although the intestine cannot absorb sodium because of the damage, it can still absorb glucose. As we absorb the glucose through the intestinal wall, the sodium is also carried through with the glucose – we call this a “coupling mechanism”. Water is then drawn into the body from the intestines as water always follows sodium. 3

Electrolytes in a spoon next to a glass of water
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Medical References

Dehydration medical references

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