Functions of Water in the Body

a jar of water

Why Do We have Water in the Body?

Water is essential and fundamental to life because of its importance and properties. Water chemically contains hydrogen (H) and oxygen (O). The chemical formula for water is –H2O, and it exists in three states, which include; liquid, solid and gaseous state. Water is tasteless, odorless, and colorless. It is also an electrolyte.

Total body water in an adult man is 42 liters, it constitutes about 50% to 60% of the body weight. It differs from infancy to adulthood. In infants, the water constitutes about 75% of the body weight. This is to inform you that babies have more water than adults. In a mature man, his body’s water content is about 45% to 60%, while in a grown woman, it is about 50% to 60%. However, in old age, it reduces to 45%.

The body comprises of two types of fluid; they are

  • Intracellular fluid
  • Extracellular fluid

The Intracellular Fluid-ICF

This is the fluid inside the cells enclosed by the plasma membrane, it is two-third of the body water (2/3 of the body water), and its volume is 28 liters. Intracellular fluid supply body cells their turgor (turgidity and tension) and a medium within which biochemical reactions occur.

Extracellular Fluid-ECF

It is the fluid outside the cells in the body, it is one-third of the body water (1/3 of the body water), and its volume is about 14 liters. The intracellular fluid supports the cells and permits the transportation of nutrient and waste products. The ECF is sub-divided into two components:

  • Interstitial fluid—the fluid that surrounds the cells in the various tissues of the body. It is about three-quarters of the ECF volume (3/4 of ECF volume). It includes water contained within the bone and the dense connective tissue.
  • Intravascular fluid–plasma—this is the fluid inside the blood vessels, which is plasma. It is about one-quarter of the ECF volume (1/4 of the ECF volume).

Percentage of Body water changes due to the body’s development because of the proportion of body water given over to various organs, muscles, bones, and other tissues that modify from infancy to adulthood.

water in glassFunctions of Water in the Body

Water is very vital to life because of its importance and the services of water in our body. It has critical roles it plays in maintaining the body system. Some of the tasks carried out by water in our body are;

  • Protection
  • Proper digestion process
  • Removal of waste
  • Dehydration prevention
  • Transportation of nutrients in the body
  • Regulation of body temperature


Water protects the body, organs, and tissues. It is water in the body that aids in moistening the eye, nose, ear, and mouth. The water also prevents these body parts from getting dry. The smooth movement of the spinal cord is favored by the lubrication from water. Asides from that, water also cushions the joints. This cushioning process helps in reducing discomfort when the body engages in physical activities like arthritis, arthralgia, and so on.

Removal of Waste

Toxins are part of our body intake from food and oxygen through digestion and respiration. The consumption of water flushes the toxic wastes in the body out. Water is a natural lubricant that is capable of softening stool and promote its evacuation from the body.

The kidney is an excretory organ that removes waste products from the blood and excretes toxic substances via urine. The kidney maintains body water balance to excrete toxin and excess fluid through the bladder. Water removes waste products via the skin by sweats and perspiration.

Proper Digestion Process

Digestion starts from the mouth as soon as you start chewing your food, then the chewing signals the salivary gland to start producing saliva, which contains enzymes that help break down the food.

It is advisable and healthy to drink water after eating. The water softens and breakdown the food to absorb nutrients. It moistens the esophagus and keeps the food moving through your throat. It moistens the intestine and makes it smooth and flexible.

Digestion ends when the leftover materials of the food are excreted from the body.

Dehydration Prevention

Dehydration is a notable reduction in the body fluids; it occurs when you lose or use more fluid from your body than the quantity you take in. These signs will tell you if you are dehydrating, extreme thirst, less regular urination, dark colored urine, tiredness, and dizziness.

Excessive sweating, fever, excessive urination, and vomiting cause dehydration, however, when you drink enough water regularly, it increases the body fluid. It is recommended to drink enough water after any physical activity.

Transportation of Nutrients in the Body

The body contains roughly five liters of blood. Oxygen and nutrients are distributed throughout the body. Water is a significant component of the blood that helps move the glucose, water-solubles, vitamins, minerals, and other nutrients throughout your body.

Regulation of Body Temperature

Water controls the internal temperature of the body in reaction to the external environment.  Water can absorb heat and transfer heat at the same time, so the body makes use of this to regulate body temperature. One of the properties of water is to act as a buffer against temperature changes.

Also, you can take care of your skin by cleaning your skin with good and clean water. The moment the water touches your skin, it softens the skin, opens the skin pores, and wash away the dirt, debris, and oil, so therefore it makes the surface clean. Let me tell you this, water has been existing right from time, and that makes it a history; water is history.

water from sweat poresHow Water Leaves the Body

Water leaves the body in so many ways in our daily activities. It is healthy for water to leave the body; nevertheless, it must be maintained in the right proportion.

  • Respiration – water leaves the body through your breath in the form of a small droplet of water.
  • Perspiration – small droplets of water leaves the body via sweat after exercise or heat.
  • Excretion – high exit strategy of water is through the kidneys in the form of urine, and another high exit strategy is in the way of stool.

It is a sign of healthiness whenever water leaves the body. Some waste products are excreted in liquid form, for example, sweat and urine, etc. The water leaving the body must be replaced to keep an enclosed system and live a healthy life.

How Much Water Should One take in a Day?

Water is essential for good health; it should be taken regularly on a daily basis. What quantity of water should you drink every day? It’s a rhetorical question that has no answer.

Your daily activities, gender, health, and place you live are factors that determine the rate at which you drink water daily.  An individual living in an arid land will take more water than someone living in savannah land.

So at least in a day drink up to “8 cups of water each day”, men are expected to drink more water than women do because women remove waste products from their bodies more than men do.  It is recommended for men to take a total of 13 cups; approximately 3 liters, while for women 10 to 12 cups; a little over 2 liters approximately.

In conclusion,

water is the most vital nutrient in the body, it should always be regulated in the right proportion. Once again, here are the signs recommended for dehydration; extreme thirst, less regular urination, dark colored urine, muscle cramp, tiredness, and dizziness. Dehydration is dangerous to the extent of killing, about 75% of the brain is made up of water.

So if the water content in the brain decreases, gravitational pull makes the water move away from the brain and thus dehydrating the body. This makes you unconscious till you get enough water or lie down flat till the water circulates throughout the body.

After any physical activities drink a clean cup of water, it regulates the internal temperature with the external temperature till it reaches the normal temperature range; 36.5 to 37.5 degrees Celsius, this is equivalent to 97.7 to 99.5 degrees Fahrenheit. Value the need for having water in your body by drinking water to replenish your body fluid.