How do we manage the water needs of our body?
We often hear that the body needs water in order to function properly and to maintain good health. But why is this? What role does water play in our organism and how much should we drink daily?
Contrary to popular belief, the body is not a composite of solid organs in which liquids circulate but rather a composite of liquids in which solids can be found. The adult human body is, in fact, composed of 70% water. This proportion of liquid is not, however, the highest level a human body can reach: a newborn is 80% water and a 4-month-old foetus is 93% water. Most of our organs are themselves composed of about 75% water, the brain being the organ with the highest percentage at 83%. The skeleton on the other hand holds the least at 22%.
The liquids that the body holds are not mixed together but separated and distributed throughout different chambers or layers situated more or less deep within the organism.
The liquid that is closest to the surface is the blood. It circulates inside the vessels and represents approximately 5% of the body’s weight. Directly beneath the blood can be found the extracellular fluid of which the lymph is a part. As its name indicates it is found outside of the cells. It surrounds them and they swim in it, filling in the tiny interstices that separate them one from the other. Its volume is equivalent to 15% of the body’s weight. The deepest chamber is the one holding the intracellular fluid, which is found inside of the cells. Although the inside space of each cell is extremely small, by adding them up these spaces nevertheless constitute a very large volume: the intracellular fluid represents, in fact, 50% of the body’s weight.
The liquids composing our body are the connecting link between our cells and the outside of the body. They carry nutrients and oxygen to the cells and in turn bring back the toxins that these produce. Without water, our body would therefore not be able to function.
The organism’s water needs
We eliminate approximately 2.5 litres of water daily: 1.5L of urine, 0.5L of sweat, 0.5L through the lungs (in the form of vapour) and through the intestines.
It is imperative that this considerable liquid elimination be compensated with an equivalent intake in order for the body to continue functioning. It is the law of equilibrium that demands it, this law that governs every physiological phenomenon. In the same way that periods of activity must be counter-balanced with rest periods, burning energy with equivalent inputs, etc. so too, must liquid eliminations be compensated through water intake.
Where does our organism find 2.5liters of water daily for its needs? Part of it is contained in food (approximately 1litre), the rest in drinks (1.5 litres). These numbers correspond with eating generous portions of fruits and vegetables due to their rich water content. However today, in general, our nourishment consists mainly of water poor foods: grains and meat. Also, they contain too much salt and are filled with toxins, which only increase the need for water. In fact, the more waste there is to eliminate, the more liquid support is necessary in order to eliminate it from the organism.
By taking these different factors into account, the World Health Organization (WHO) recommends an average intake of 2 litres of water per day. Where does our personal liquid consumption stands in regards to these 2 litres? Is it inferior or superior? Or does it correspond with this number?
In order to know one must measure the volume of each liquid consumption during the day. The intake can vary from one day to the next therefore it is a good idea to take these measures over three or four consecutive days. An important point: water and herbal teas (unsweetened) count for a full measure but it is not the same for coffee, tea, chocolate and commercial drinks, as well as wine and beer that count as only half measures. These latter drinks are not as hydrating as the first ones mentioned because of their high sugar and alcohol content as well as other substances. A portion of the liquid that they contain is used to neutralize and eliminate these undesirable contents.
Because man always has an abundance of water at his disposal he does not think how brief is the time that he can go without drinking and consequently the short road that leads to dehydration and death.
It was, in fact, calculated that grave dehydration problems arise after 3 days of total deprivation and that death ensues 3 or 4 days later. People lost in the desert, people shipwrecked or miners trapped in a gallery, reach this point of no return. But besides these extreme cases of dehydration there also exists chronic dehydration where the water deficiency is never enough to lead to a critical situation but yet important enough to lead to health problems.
What happens when the body does not receive sufficient liquids? First of all the blood loses volume. It constantly yields its water content to the kidneys, the sweat glands as well as to the rest of the excretory system. Its volume cannot however, diminish very much. The body then reacts by drawing liquid from the extracellular matrix. The blood volume is then re-established but the extracellular liquid is then reduced causing the exchanges between the blood and cells to not work as well. In order to remedy the liquid deficit on the extracellular level, the body must once again find a helping solution. It will do so by drawing liquid from inside of the cells. These latter will in turn dehydrate and their capacity to work will consequently diminish. In this way, the body becomes deprived of water within the deeper and deeper layers.
Two major resulting metabolic disturbances will occur and originate from all the troubles of dehydration. The first is a slowing down of enzyme activity. Enzymes, which are responsible for all biochemical reactions within the body, work all the less efficiently when the organic liquids are thick and viscous. Energy, hormone production and reparative substance production, all necessary for proper functioning of the organism, decline rapidly.
The second major metabolic disturbance is an autointoxication of the organism. Toxin eliminations continue to take place but with a smaller amount of liquid. Urine becomes thick, sweat more concentrated and stools are drier. Under these conditions toxic elimination is forcibly less efficient since the support to evacuate is inadequate.
Specifically, chronic dehydration can bring on the following problems: fatigue and chronic lack of energy (through the slowing down of enzyme production), constipation (stools become too dry and hard), digestive troubles (through insufficient liquid in order to produce digestive secretion), hypotension (through lack of blood volume), gastritis and stomach ulcers (mucus deficiency that protects the gastric lining), respiratory problems (through the drying up of mucus), eczema (skin eruptions due to sweat that is heavily concentrated), cystitis (heavily concentrated urine leading to micro lesions allowing bacteria to grow). Excess weight can also result indirectly from dehydration. Some people sadly often confuse thirst with hunger. Eating can, however, get rid of thirst because of the liquids contained in foods. This liquid intake is, however, accompanied by a calorie intake that in the long run leads to weight gain. An overweight person should, therefore, drink a lot more water to curb false hunger sensations, but equally because large quantities of liquids ingested forces the body to burn calories.
Fatigue and a lack of energy remain one of the biggest symptoms of dehydration yet a regain in energy and liveliness is the first effect to manifest when a person who did not drink enough starts to drink sufficiently.
Thirst is the body’s alarm that goes off when it starts running out of water. It not only incites us to drink, but to drink enough in order to correct the hydrous deficit.
Some people admit to not feeling a thirsty sensation and consequently drink very little.
Quite often this results in them not drinking in spite of the thirsty signals emitted by the body, which in turn begin to manifest in an increasingly discreet manner and end up by almost completely disappearing.
Thankfully, as with all physiological functions, a dormant thirsty sensation can be reawakened. It suffices for such a person to force himself to drink normally, even if he does not feel the need. After a few days he will then notice, with surprise, how thirsty he is in spite of all that he drinks!
What should we drink?
The ideal drink for human beings is water as it is the only one offered by nature. In order to drink approximately two litres a day it must taste good.
Tap water is usually good but if this is not the case there are three possible solutions.
Water filters can be used that rid the water of excess chlorine and other impurities. Also by filling a pitcher of water and letting it sit in the refrigerator the chlorine will evaporate leaving the water with a better taste.
The third solution consists of drinking bottled spring water or slightly mineralized mineral water. It makes no difference if the bottled water is still or sparkling, it is simply a question of personal taste. It can likewise be drank cold, warm or also for some, hot.
It is preferable physiologically to spread our water consumption over the day rather than to «fill up» once or twice a day. In this latter case the volume ingested in one single shot would be too great. It is normal to drink at meals because it helps to humidify and dilute dry foods but the larger part of drinking liquids should be done in between meals.
The rule of thumb: «drink every time you feel thirsty» is therefore relevant and the best way to follow this is, and remains, to drink water!