You Should Drink Water, but Why and How Much?
Water is one of very few vital needs for human beings. But what role does water play in our body?
A healthy sedentary adult living in a temperate climate should drink at least 1.5 liters of water per day . This level of water intake balances water loss and helps keeping the body properly hydrated.
The water you consume through food and drinks follows a very precise route to arrive in your cells, of which it is a vital constituent.
After passing through the stomach, water enters the small intestine, where it is largely absorbed in the first sections, the duodenum and jejunum. The rest passes into the colon. It crosses the intestinal mucous membrane into the bloodstream, then into the interstitial tissues that make up the framework of every organ, to arrive in the cells.
Blood brings nutritional elements to cells (minerals, vitamins, protein components, lipids and carbohydrates). Waste products are then removes through urines. Water plays also an essential function in helping the regulation of temperature.
The main functions of water in the body
Human body is made up largely of water. It serves vital functions:
1. Cell life
Water is essential for cells to function properly: it enters into the composition of the cells. Water is necessary for the life of the cell because it delivers the nutritional elements it needs, like minerals (sodium, potassium, calcium…), trace elements (iodine, selenium, zinc…) and vitamins. Water is also an excellent solvent for glucose (the main fuel of the brain) and the amino acids necessary for the synthesis of proteins in cells.
2. Chemical and metabolic reactions
By enabling hydrolysis reactions, water participates in the biochemical breakdown of what we eat (proteins, lipids and carbohydrates). This is one of many reactions in which water is involved. For example, water enables hydrolysis reactions like those of proteins, lipids and carbohydrates, which require water molecules. The H20 molecule is consumed in these metabolic reactions. But other metabolic reactions can, on the other hand, produce and release water molecules; this is referred to as “metabolic water” or “endogenous water.” The amount of water produced depends on whether it derives from the oxidation of proteins, lipids or carbohydrates. So, within the framework of a balanced diet of a sedentary person, the body is capable of producing 250-350 ml of metabolic (or endogenous) water a day.
3. Transport of nutrients and removal of waste
Water contributes to the transport of nutrients to the cells. It also helps removing waste products through urines. An important source of waste comes from proteins, in the form of nitrogenous waste (urea, creatinine, ammonium ions, urates). They are eliminated via urine after an intense process of filtration, reabsorption, secretion and elimination in the kidneys. So to be healthy, it is important to drink water in order to eliminate it!
4. Body temperature regulation
Water has a large heat capacity which helps limit changes in body temperature in a warm or a cold environment. Water enables the body to release heat when ambient temperature is higher than body temperature: we begin to sweat, and the evaporation of water from the skin surface cools the body very efficiently. Sweating means loss of water and the risk of dehydration in case of insufficient intake of water. We can lose a significant amount of water via sweat, from 0.5 to over a full liter per hour! It’s recommended to drink regularly during exercise, especially if it’s intense.
5. A lubricant and shock absorber
Water, in combination with other viscous molecules, form a lubricant surrounding the joints. It also acts as a shock absorber for eyes, the brain, the spinal cord and even for the fetus in amniotic fluid.
Water is at the heart of life. This is why a human being can survive no longer than few days without water.
Certain organs and body parts are particularly rich in water: kidneys (79% water); heart (73% water) , lungs (83%); brain (73%); liver (71%); skin (64%); bone (31%); adipose tissue teeth (10%). Since muscles contain more water than adipose tissue, a muscular person has a larger proportion of water in his body than a person with more adipose tissue.
Dehydration can impact the proper functioning of the body.
Drinking water every day (approximately 1.5 liters*), and at regular intervals, 8 times a day (before, during and in-between meals), without waiting until you’re thirsty, is important as part of a healthy lifestyle, at every stage of life!
*And How Much Water?
Total Water requirements are particularly elevated during periods of growth, increasing from a recommendation of 1.3 liters per day (total water consumption from drinks and food) for a child 2-3 years old to 2 or 2.5 liters a day for an adult (women and men, respectively) as defined in Europe by the EFSA. On average, 20-30% of water intake comes from food (mainly vegetables and fruits) and 70-80% from drinks. So, for an healthy sedentary adult living in a temperate climate, at least 1.5 liters of water should be drunk each day. Naturally, this quantity must be adapted to the age, gender, climate, and level of physical activity.
Also you can use following formula to calculate your daily water intake:
Weight (kilogram [kg]) x 25-35 milliliter (mL)=mL fluid required daily.
74 kg X 35 milliliter = 2590 mL