The Importance of Water for the Human Body

The human body consists of about 60 per cent water, an amount that varies with age, sex and the proportion of muscle tissue and fat.

Approximately 25 liters of water are distributed throughout the cells of the average adult body. Some parts of the body are more water than anything else: the body’s muscles contain about 75 per cent water, and blood plasma is almost all water (more than 90 per cent). Water also plays an important role in cushioning the joints and internal organs, lubricating body tissues such as the eyes, lungs and air passages, and protecting the fetus during pregnancy.

Of all the essential nutrients, water is the most critical. A human being can survive on the body’s store of food for as long as 10 weeks, but without water intake life would be over in a few days. Every function of the body uses water. It is needed for digestion, absorption, circulation and excretion; for transporting nutrients, helping to build tissue and maintaining body temperature.

Large amounts of water are constantly lost through perspiration and other bodily functions. As much as 300ml may be exhaled from the lungs every day and about 900ml may be lost through perspiration. This amount increases drastically in warm weather or during exercise. In very hot, dry climates the water loss may be 10 times higher.

The body’s control mechanism for ensuring an adequate water intake is thirst. Never ignore thirst – inadequate replacement of water can result in dehydration or heat exhaustion. Always take in more water than just to replace lost water. Most experts agree that the liquid equivalent to six or eight classes of water per day is sufficient for adults. Remember, alcohol does not count in this equation! Actually, alcohol intake affects water requirements: 50ml of whiskey for instance requires 200ml of water to metabolize it!

People who are involved in any strenuous physical activities as well as those who are working outdoors should ensure an adequate intake of water. The relatively large amount of weight an athlete may lose during exercise or competition is largely a loss of water, in the region of 4-6 liters. Loss of more than 10 per cent of body weight in water can result in dehydration. Under conditions of prolonged strenuous activity, for example cycling tours or marathon running, the thirst signal may fail and dehydration, leading to impaired performance or even collapse may occur.

Although liquids such as water, tea, coffee, juices, etc. are the largest suppliers of water to the body, solid foods make a contribution too. The average person needs at least three liters of water a day. About one liter of this comes from the food we eat. Most fruits and vegetables are about 80 per cent water, cooked spaghetti is about 60 per cent water and meats are about 50 per cent water.

Water is still the world’s oldest and best health drink – it is essential for good health, good skin and most of the body’s functions.

Image source: Microsoft.com