Did you know that 60% of our bodies are made up of water? But every day, our bodies evacuate several litres of water (around 2 or 2.5 litres) through urine, perspiration and even breathing. In addition, the human body does not store water. It is therefore essential to compensate for these losses with good hydration in order to maintain optimal functioning of the body.

Why should you drink water?

To live! Our bodies cannot live without water intake for several reasons.

Blood contains water and constantly circulates throughout our body. It allows the transport of oxygen to the muscles and brain.

The kidneys are the filters in our body and are responsible for the production of urine. The blood filtered by the kidneys is thus cleaned and the undesirable elements (toxins, metabolic waste, etc.) are removed from the body through urine. Urine contains not only blood waste but also, and above all, water waste. Through the action of the kidneys, our bladder drains around 1.5 L of urine (composed of 90% water) per day. A loss that needs to be compensated!

Water also helps regulate our body temperature. It must be between 36.1° and 37.8°.  But when it’s too hot, during physical exertion or a fevery episode, the body temperature rises. It is perspiration, and therefore the water present in the body, that will regulate this excess, cooling the body and therefore regulating the temperature.

And if there’s sweat, there should be hydration! This is why you need to hydrate even more in the summer or during physical activity.

The digestive system needs water to properly perform its task. To promote digestion, our bodies provide water to the stomach and small intestine to help transport food. Most of this water will be returned to the bloodstream through the walls of the small intestine, while the rest will follow the waste circuit to be released in the faeces.

Saliva is also an essential tool for digestion. It helps to chew and absorb elements. Since it is 99% water, good hydration will have an impact on diet and digestion.

Made up of 80% water, the skin requires proper maintenance in order to avoid premature ageing or drying. Drinking water helps renew the cells and restores suppleness and vitality to the skin.

Drinking water is thus vital to maintain all these bodily functions optimally.

Daily hydration

Some tips for good hydration

Don't wait until you're thirsty

Thirst is already a first sign of dehydration. You need to adopt good habits and drink water regularly throughout the day, even if you don't feel thirsty.

Drink small amounts of water

Our bodies need water throughout the day. It is therefore better to drink small amounts of water regularly during the day, than a large amount of water from time to time.

Find satisfactory alternatives

If you don't enjoy drinking water, you can find alternatives: flavoured water, broths, tea, sparkling water... all small things that can promote daily hydration. Be careful, water cannot be replaced by juices, sodas, or other sugary drinks.

Eat fruits and vegetables

Our bodies absorb about 1 L of water per day through our diet. It is therefore necessary to consume fruits and vegetables for optimal hydration.

In the event of physical activity or extreme heat

If our body is hot, it sweats and releases more water. It is necessary to compensate for this greater loss with greater hydration. Drinking more in summer does not mean, however, not drinking in winter. Changes in temperature between indoors and outdoors, humidity, etc. also require our water capital to regulate body temperature.

Increased vigilance in certain cases

Some more fragile people may be more susceptible to dehydration. This is the case for older people who feel less thirst than younger people. It is therefore necessary to be vigilant and take the initiative, especially as age-related physical complications require a greater intake of water (taking medication means more urine has to be passed, diabetes, fever, etc.).

This is also the case for pregnant women. Blood volume increases during pregnancy to irrigate the placenta. The amount of water absorbed should therefore be from 1.5 L to 2 L of water per day. This will also prevent urinary tract infections, which are common during pregnancy. For breastfeeding women, good hydration habits taken during pregnancy should be maintained or even increased. Breast milk contains a lot of water, so a breastfeeding mother’s body releases far more than the 2.5 L of water it needs every day.

Finally, you also need to be vigilant when it comes to hydrating your baby, especially in hot weather and in case of diarrhoea. Infants do not display their thirst, so it is important to offer them something to drink regularly and to check their fontanelle.

Recognise dehydration

When the body drains too much water (in case of vomiting, diarrhoea, heat wave, over-exertion, etc.) or when the body’s water requirements are not met, the risk of dehydration is increased.

Symptoms vary depending on the profile of the person affected:

Children and adults



The first symptoms

– Thirst

– Dry lips

– Fatigue 

Symptoms of advanced dehydratation

– Dry mouth

– Thirst

– Dry, cold skin

– Fever

– Headache

– Weak and dark urine

– Dizziness malaise

– Hard stools

– Weakness, apathy

Apathy, heavy sleep, groaning

Pale skin

-Circles around the eyes

Accelerated breathing

-Significant weight loss (>5%)

– Hard stools

-Incessant vomiting

– Hollow fontanelle

-Loss of appetite




The feeling of thirst is not one of them, since it is often felt too late in the elderly.


        Sante-pratique-Paris.fr, Pourquoi l’hydratation est importante pour votre corps ? 2023, https://sante-pratique-paris.fr/bonnes-pratiques-dossier/pourquoi-lhydratation-est-importante-pour-votre-corps/

        Philippe Beaulieu, « Boire de l’eau : un acte essentiel pour notre santé », Le centre d’information de l’eau, https://www.cieau.com/leau-et-votre-sante/eau-hydratation-et-hygiene/hydratation/pourquoi-doit-on-boire-de-leau/

        Dominique Armand, « Découvrir l’eau », Sagascience, 2000, https://www.cnrs.fr/cw/dossiers/doseau/decouv/rubrique.html

        Ameli.fr, Déshydratation, 2022, https://www.ameli.fr/assure/sante/urgence/pathologies/deshydratation


        ANSES, Eau de boisson : bonnes pratiques de consommation, 2020, https://www.anses.fr/fr/content/eau-de-boisson-bonnes-pratiques-de-consommation#:~:text=Il%20est%20recommand%C3%A9%20de%20boire,sensation%20de%20soif%20est%20amoindrie.