Water is the main component of the body: it represents around 60% of the weight of an adult's body. A little more in infants (~75%), and a little less in elder persons (50%) (1).
Water, presents in each cell and organs of the human body, plays several key roles. It acts first as a building material. Water is also a solvent, a reaction medium, a reactant and a reaction product. It helps to keep the body at the right temperature, through its evaporation at the surface of the skin. Moreover, water in the body transports nutrients to cells – it is the major component of blood (blood is 92% of water). Therefore, it maintains vascular volume and allows blood circulation which is essential for the good functioning of the different organs of the body. Water also helps removes waste products from the body. (1)
In other words, not drinking enough water may, sooner or later, leads to dehydration. That is how important water is!
What does "not drinking enough water" mean?
An individual's water needs depend on his age, his gender, the climate, his physical activity… (1-2). However, there is a recommendation: it is estimated that a healthy sedentary adult, living in temperate climate, should drink in average 1.5 liters of water per day (1).
What happens if you don't?
An insufficient water intake disturbs the water balance. Indeed, to maintain the water balance, the water inputs must be equal to the equal outputs. Water intakes are composed of: the water you drink (~ 1.5 liter per day*), the water you eat (on average 675 ml per day) and the water your body produce (around 300ml per day). Water outputs include: the water you lose via urine (around 1.6 liters per day), the water lost through the skin (approximately 450ml per day) and the lungs (~300ml/d), and finally the water in the feces (~200ml/d). (1)
When you maintain the water balance, you stay well hydrated. On the other hand, if the water intakes are lower than the water losses, you can experience a hydration deficit and thus one step further becoming dehydrated.
*For a healthy sedentary adult living in temperate climate
What are the consequences of the dehydration ?
Let's talk especially about people who do not drink enough every day: For instance, they drink 1 liter per day instead of the 1.5 liter recommended for a healthy sedentary adult living in temperate climate. Let's have a look at the consequences on short, medium and long term…