It is often said that the human body is made up mostly of water, and it is that on average the 65% of body weight It's due to the water.
However, this figure is an average figure calculated considering all ages and sexes, but in the elderly it is usually lower, in babies it is usually higher and in men it is usually higher than in women.
The reality is that the amount of water in the human body may vary from 50 to 75% at different stages of life:
- Adults: between 50-65%.
- Babies and children: up to 78% in newborns, drops to 65% from 1 year of age.
- Seniors: <50%.
In addition, the percentage of water, like other characteristics of body composition, presents a clear relationship with gender, physical condition, and amount of adipose tissue. Fat tissue is one of the tissues with less water, only 10%.
An average male adult has a percentage of water around 60% (58 ± 8%), while the woman is around 50% (48 ± 6%). This is due, among other reasons, to the fact that women tend to have a higher percentage of adipose tissue naturally. For the same reason, overweight people have a lower percentage of water.
- Babies and children have the highest percentage of water
- Grown men follow
- Adult women have less water than men and children.
- Obese and overweight people are the ones with the lowest percentage of water, they can reach even to be below 45%.
In addition to age, sex and complexion, the percentage of water changes due to many other factors; For example, by the level of hydration or the health condition.
The feeling of thirst appears when 2-3% of body water is lost. Mental performance and physical coordination can be affected even earlier, starting at 1% dehydration.
Distribution of water in the human body
Body water can appear as free fluid or as part of other substances and tissues.
Most of the body's water is found in the inside of cells forming part of cytoplasmic fluid. This water represents approximately two-thirds of all body water.
The rest, approximately a third, corresponds to the water of extracellular fluids.
Thus, a person with 70kg weightyou can have some 40 liters of water in your body divided into several fluids:
- intracellular fluid: about 25 liters would be inside the cells.
- extracellular fluids: about 15 liters would be in fluids such as plasma, interstitial fluid, gastrointestinal, cerebrospinal, ocular fluids, etc.
In addition, the distribution of body water is not homogeneous between the different organs and tissues. 90% of the blood is water, which represents 20% of the total body water. The brain and lungs have ∼80%, kidneys, muscles and heart 75%, skin 65%, and bones around 30%, always bearing in mind that these data are quite variable.
body water function
The water is essential to any known life form on planet Earth, who knows if there will be other forms of life in the Universe that do not need water. Among its functions, the following stand out:
- Is the principal solvent of the body. Dissolves minerals, water-soluble vitamins and numerous nutrients.
- as a solvent, transports nutrients and oxygen to cells.
- Essential in the formation of the lubricating fluid of the joints.
- Act like thermal damper to regulate the internal temperature. This is largely because water has a high specific heat. Water is also involved in thermal regulation by perspiration.
- Main component in many fluids: saliva, blood, sweat, etc.
- Absorbs shocks to various organs, eg brain and spinal cord.
- Through the water numerous waste and toxic substancesfor example through urine or sweat.
For prevent dehydration and maintain optimal water levelit is recommended to drink 2 liters a day or 30 ml per kg of body weight, although the specific needs of each person may change according to their physical situation and state of health.