Water is the main component of our body. A man is about 65% water, and a woman is 60%. To function optimally, your water percentage must not fall below a certain level.

Indeed, water is a crucial fuel for a well-functioning body. For example, water aids in the transport of oxygen and nutrients throughout the body, as well as the regulation of body temperature and the digestion of food.

As a result, knowing how much water you need to drink each day is critical.

How many liters of water can you drink per day?

The ‘rule’ of eight glasses of water per day is not really supported by science. Everyone is different – and every day is different, so you must adjust your water consumption to those changes.

For example, if you work in a warm, humid environment, if you are an athlete who exercises more intensely than the average person, you need more water regardless of your weight.

Children under 12

From the age of 1, it is recommended that children drink almost the same amount of water as that recommended to adults, namely, 1.5 liters of water per day. Indeed, the child’s water needs increase as a result of their growth.

However, during physical activity and in hot weather, children under 12 should drink at least 2 liters of water per day.


Adolescents should consume 2.5 to 3 liters of water per day, which is more than adults of similar weight.

A study by researchers at Harvard University found that nearly one in two American teenagers do not drink enough water. The reason? Almost 25% of them say they prefer juices, soft drinks, and other alternatives.


Adults may move a little less than their offspring, but they still need to stay hydrated. It is generally recommended to drink a minimum of 1.5 to 2 liters of water per day.

However, not everyone has the same needs. To find out the amount that’s right for you, multiply your weight in kilograms (kg) by 30 milliliters (ml).

For example, a person, weighing 70 kg, needs about 2000 ml or 2 liters of water per day. However, this amount can increase depending on certain factors, such as training, physical conditions, environment, and the weather.


The water need of an athlete is even greater. It is recommended that athletes drink half a liter of water a few hours before each workout and continue to drink throughout the workout, at the rate of about one liter of water per hour of physical activity.

The elderly

For people aged 60 or older, the formula changes a little, as the body’s water content decreases as we age. To find the recommended daily amount of water for a person over 60 years old, simply multiply their weight in kg by 25 ml.

Make sure to distribute this amount evenly throughout the day.

Benefits of drinking enough water

Water balances body fluids

The essential function of water is the good circulation of fluids in the body. In this context, water is particularly important for digestion, blood circulation, maintenance of body temperature, and saliva secretion.

Energizes the muscles

Water helps to energize muscles. When muscle cells don’t have enough fluids, they don’t function as well, and their performance can suffer. So, drinking enough fluids is important when exercising.

Helps keep the skin beautiful

The skin contains a lot of water and acts as a protective barrier against excessive fluid loss. Proper hydration gives the skin a fresher appearance, preserves its radiance, and delays the appearance of wrinkles.

Contributes to weight loss

Water is an ally, but it shouldn’t be seen as a way to lose weight. It works primarily as an appetite suppressant. For example, it is recommended to drink one or two glasses for about 30 minutes before having a major meal.

Promotes weight loss

Water also speeds up metabolic activity, which burns more calories. It is even better to drink cold water, as the body will use more energy to heat the water to body temperature.

Improves cognitive performance

Consuming plenty of water improves cognitive performance and has a direct beneficial effect on short-term memory. The effects are particularly noticeable in children in school.

This is a subject not to be taken lightly because according to the study “Effects of additional water consumption at school on cognitive performance in children” from the University of Cagliari, 84% of children start their school day with mild dehydration.

It is therefore essential that a child is properly hydrated throughout the day.

Avoid any excess

While drinking water is necessary for the proper functioning of the body, drinking too much water can conversely cause some serious damage.

The term to define overhydration is hyponatremia. It occurs when a person drinks too much water quickly. The water then dilutes the concentration of electrolytes in the blood, including sodium, the main electrolyte.

Hyponatremia causes water to enter all parts of the body, including the brain, in a phenomenon called osmosis. The pressure then exerted on the brain, trapped in the cranium, has neurological consequences.

Symptoms associated with hyponatremia are dizziness, confusion, feeling extremely tired. It can even lead to coma and death.

Overhydration often happens in extreme sports, especially marathons, where competitors often have an incorrect perception of thirst.

Knowing that the kidney can only filter or excrete about 1 liter of water per hour, as soon as this quantity is exceeded, we are exposed to an accumulation of fluid in the body.

To prevent such complications, please respect the recommended amounts.

Water replacements

No other drink can replace water for optimal hydration. However, if you find it hard to fulfill your daily water requirement, you can also replenish with other drinks like the following:

  • Black and green tea: tea contains no calories. The advice for adults is to drink up to 3 cups of green or black tea in a day. Besides hydration, tea also lowers blood pressure and reduces the risk of stroke. Tea contains caffeine, which stimulates the nervous system. Children under 13 can drink up to about 1 to 2 cups a day.
  • Herbal tea: herbal tea contains no calories and no caffeine. Herbal tea is officially not a tea but an herbal extract. The advice is not too much, but for example to drink a maximum of a few cups a day. And not to drink the same herbal tea over and over again, but to alternate.
  • Smoothies: smoothies can be used for lunch or snacks but are also very nutritious hydrating drinks. You can find recipes all over the internet.
  • Coconut water: coconut water is one of the best alternatives to water. Natural, hydrating, and rich in nutrients and vitamins; you should give it a try.
  • Milk: despite its thick appearance, milk is actually a very hydrating drink. Furthermore, along with calcium and vitamin D, milk contains the protein needed to give you energy on a hot summer day.
  • Fruit juice: fruit juice is around 85% water, which makes it very hydrating. Vitamins from real fruit are also good for your health. However, pay special attention to the amount of added sugars that juices may contain, as they prevent hydration. If you drink a lot of fruit juice, you can dilute it with water.
  • Coffee: coffee contains almost no calories. Drinking coffee is also associated with a lower risk of heart disease, stroke, and type 2 diabetes. Adults can drink up to 4 cups of coffee a day because of the caffeine.


Water is an essential element for the well-functioning of our body. Indeed, the human body is more than 60 percent water, and water participates in a wide range of vital functions. Not drinking enough water can lead to chronic dehydration, coma, or even death. It is, therefore, necessary for us to drink enough water on a daily basis.