Representing close to 70 percent of our body mass, water is the most essential element of all nutrients. Our body keeps modest reserves of water and constant hydration is vital: even a two percent loss of hydration can lead to lowered athletic performance and the worst case scenarios can even lead to death.
The role of water in the body
There are 3 major roles of water in our bodies:
Structural : as the main component of cells and tissues. Without water there would be no cells or living organisms.
Functional: transport of nutrients (proteins, carbohydrates, fats, vitamins, minerals and trace elements), disposal of toxins and waste products, electrolytic. A few of our body “elements” are in liquid state (blood, plasma, lymph ), and this state is due to the water which is the main component.
Cooling: as a way to cool our body – by sweating. Water helps regulate our body temperature as you surely know to be maintained at around 36.5 degrees Celsius.
Dehydration and Re-hydration
As you know we are all different, and this also applies to our body composition. Age, sex, and especially body composition – the amount of muscle mass and fat we carry – greatly influence the amount of water our body holds. Indeed, the muscle is 70% water so that body fat contains only 23%. This explains the smaller size of people that carry more muscle opposed to those that carry more fat mass.
Depending on the individual and body composition, the body loses generally 1.7 to 2.4 liters of water a day (urination, respiration, transpiration etc.). These losses must be re-filled in order to maintain body’s water balance, otherwise dehydration happens.
The re-hydration happens in two ways:
– Through the food you eat (a daily diet of 2500 kcal per day brings 1-1.5 L of water anyway),
– The rest should come from beverages: 1-2 L, to make up losses. Do not drink too much during meals to avoid overloading the stomach. Drinking fluids is preferred before or after your meal.
Water is the only essential drink that does not have calories. All other drinks contain some calories such as sugar (4 kcal / g) or alcohol (7kcal/g) , as well as vitamins and minerals.