How much water do you really need to drink?

how much water do you need to drink

Human beings can survive without food for 30 to 40 days. But without water, life would end in 3 to 5 days.

Water is an essential nutrient that is involved in every function of the body. No wonder the human body is two-thirds water.

Why our bodies need water

The function of water in our bodies can be summarised as follows:

  • Helps to transports nutrients and waste products in and out of cells;
  • Necessary for all our digestive, absorptive, circulatory and excretory functions;
  • Required for the utilisation of water-soluble vitamins; and
  • Needed for maintaining body temperature.

Why do we get thirsty?

Replacing the water that is continually being lost through sweating and elimination is very important. When the water content in our bodies drop, it causes a decline in blood volume.  This in turn triggers the brain’s thirst centre (hypothalamus) to send out a demand for a drink. The result is a slight rise in the concentration of sodium in the blood, which triggers a sensation of thirst.

As we age, the sense of thirst may become dulled. This, together with the fact that older people have a lower percentage of reserve body water, are important considerations for possible dehydration in the elderly. They must drink water, even if they do not feel thirsty.

Inadequate water consumption and our health

Bladder and bowel problems, as well as headaches, can be reduced by drinking water. Water flushes the toxins out of our bodies. When not drinking enough water, toxins can build up in the body.  This causes headaches as a result of the built-up of metabolic waste. It could also lead to kidney damage.

Furthermore, inadequate water consumption may contribute to excess body fat, poor muscle tone and digestive problems.  The poor functioning of organs (including the brain), muscle and joint soreness and water retention are other consequences.

Adequate water consumption, on the other hand, can slow the aging process and can improve or prevent arthritis and constipation.  It can also prevent the formation of kidney stones, obesity, cataracts, diabetes, low blood sugar level and many other diseases.

How much water should you drink each day?

This is a simple question with no easy answer.

A person’s water needs depend on many factors, including their health, how active they are and where they live. There is no single formula that fits everyone.

An adequate daily fluid intake is generally considered as:

  • About 3.7 liters of fluids for men; and
  • About 2.7 liters of fluids a day for women.

The Institute for Medicine makes the following broad recommendations for children and adults:

Daily recommended amount of water

These recommendations include fluids from water, other beverages and food. About 20 % of our daily fluid intake comes from the food we eat; the rest from drinks.

Factors that influence water needs

Several factors affect our individual fluid needs:

  • Exercise – any activity that makes you sweat, will require you to drink extra water to cover the fluid loss.
  • Environment – hot or humid weather can make you sweat and requires additional fluid intake.
  • Overall health – your body loses fluids when you have a fever, vomit or have diarrhea. Other conditions that may require increased fluid intake include bladder infections and urinary tract stones.
  • Pregnancy and breast-feeding – pregnant or breast-feeding women need additional fluids to stay hydrated.

Good sources of water

You don’t need to rely only on what you drink to meet your fluid needs. What you eat also provides water, for example, fruits and vegetables are good sources of water.

Beverages such as milk, juice and herbal teas are composed mostly of water. Even caffeinated drinks such as coffee and soda can contribute to your daily water intake. But remember – water will always be your best source.

Hydration check

If you rarely feel thirsty, or your urine is colourless or slightly yellow, your fluid intake is probably adequate.

And remember – drink a glass of water with each meal and between each meal, as well as before, during and after exercise.


By Elmarie Jensen



Phyllis, A & Balch, JF. 2000. Prescription for Nutritional Healing. 3rd edition. New York: Penguin Putnam Inc.


The Content on this site is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.

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