Water in Human Body
By weight, the average human adult male is approximately 55%-75% water. However, there can be considerable variation in body water percentage based on a number of factors like age, health, weight, and sex. In a large study of adults of all ages and both sexes, the adult human body averaged ~ 65% water. However, this varied substantially by age, sex, and adiposity (amount of fat in body composition). The figure for water fraction by weight in this sample was found to be 48 ± 6% for females and 58 ±8% water for males.
Water - A Vital Nutrient :
Water is essential for the human body to function. The body cannot store water and must have fresh supplies every day to perform virtually every metabolic process. Babies and the elderly are vulnerable to lack of water or dehydration. Not drinking enough water increases the risk of kidney stones and, in women, urinary tract infections.
The human body can last weeks without food, but only days without water. The body is made up of 50 to 75 per cent water. Water forms the basis of blood, digestive juices, urine and perspiration, and is contained in lean muscle, fat and bones.
As the body can’t store water, we need fresh supplies every day to make up for losses from the lungs, skin, urine and faeces . The amount we need depends on our body size, metabolism, the weather, the food we eat and our activity levels.
Importance of Water in Human Body :
Water is needed for most body functions, including to :
- Maintain the health and integrity of every cell in the body
- Keep the bloodstream liquid enough to flow through blood vessels
- Help eliminate the by-products of the body’s metabolism, excess electrolytes (for example, sodium and potassium), and urea, which is a waste product formed through the processing of dietary protein
- Regulate body temperature through sweating
- Moisten mucous membranes such as those of the lungs and mouth
- Lubricate and cushion joints
- Reduce the risk of cystitis by keeping the bladder clear of bacteria
- Aid digestion and prevent constipation
- Moisturise the skin to maintain its texture and appearance
- Carry nutrients and oxygen to cells
- Serve as a shock absorber inside the eyes, spinal cord and in the amniotic sac surrounding the foetus in pregnancy.
Not drinking enough water can increase the risk of kidney stones and, in women, urinary tract infections. It can also lower your physical and mental performance, and salivary gland function, and lead to dehydration.Dehydration occurs when the water content of the body is too low. This is easily fixed by increasing fluid intake.
Water Cycle :
The water cycle
is a continuous cycle where water evaporates, travels into the air and becomes part of a cloud, falls down to earth as precipitation, and then evaporates again. This repeats again and again in a never-ending cycle. Water keeps moving and changing from a solid to a liquid to a gas, over and over again.
that travels over the ground surface and helps to fill lakes and rivers. It also percolates
or moves downward through openings in the soil to replenish aquifers
under the ground. Some places receive more precipitation
than others do. These areas are usually close to oceans or large bodies of water that allow more water to evaporate
and form clouds. Other areas receive less precipitation
. Often these areas are far from water or near mountains. As clouds move up and over mountains, the water vapour condenses to form precipitation and freezes. Snow falls on the peaks.
- Evaporation is the process where water changes from a liquid to a gas. When water vapor (or droplets) come together in the sky, they form clouds.
- Condensation is the process by which water changes from a gas to a solid or liquid.
- Precipitation is the process by which the condensed water in the clouds returns to the earth. Depending on the temperature, precipitation can be as rain, snow, ice.
- Collection where it may fall back in the oceans, lakes or rivers or it may end up on land, where it will soak into the earth.