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, gender, 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.
The excess water is excreted in the urine, and essential for allowing the removal of nitrogenous waste (following ingestion of protein) by the kidneys. So the more protein we eat (of course in reasonable limits) the more water is needed to wash away the waste co-products.
In the case of a high-carbohydrate diet, about 2.5 grams of water are needed for the storage of 1 gram of glycogen. This means that water is also important for successful glycogen storage.
During exercise the body loses water at an increased rate as a cause of respiration. This is why your weight can be different before and after an intense workout. Poor hydration can cause poor athletic performance, decreased mental performance, cramps, vomiting and in extreme cases mortality.
The best way to stay hydrated during exercise
The capacity of the body to absorb fluids is limited and this is why we must plan ahead and drink sips of water regularly every 15-20 minutes before we start our workout. This will ensure the best state of hydration.
For sports drinks (purchased or homemade), you must monitor the content of sugars and minerals. Isotonic beverages (containing a concentration equal to that of the body) are assimilated at an optimal speed.
Too many carbs, or not enough, and your sports drink loses the ability to re-hydrate you optimally (pure water absorption can hydrate you less balanced than an isotonic drink under certain conditions during exercise).
The conclusion ? Assuming you are already hydrated well, you should drink 100-150 ml of water every 10-15 minutes.