Jul 01, 2024

Body Water: Percentage and Ratios You Should Know

Water is everywhere, and we consume it daily, but do we know how important it is? Most people are shocked to learn that it makes up over 60% of our organs and the body in general.

The all-important H2O helps our bodies function properly. However, although we constantly drink water, we lose a huge percentage of it through the skin, urine, breathing, and sweating. For this reason, we must find the perfect body water balance.

In the article below, we’ll explain the basics of body water, tell you how much of it you need, explain the difference between intracellular and extracellular water, and discuss the importance of hydration.

Body Water Explained

Body water refers to the total amount of fluid in one’s body. Water is vital for every system inside, as it functions as the building block for cells, regulates body temperature, dissolves minerals and nutrients, moisturizes the skin, protects the organs, and strengthens the muscles.

Overall, our entire body weight is made of 45%–65% of water. When we are born, this number is even higher and goes up to 80%. As we age, the percentage drops to 60%–65%. Body water also differs from one individual to the other, as it depends not only on age but also on gender and body weight (each individual has a different amount of fat and lean mass).

Where Is Water Stored?

If you wonder where all that water in our bodies is stored, the answer is — everywhere. It resides in our organs, tissues, blood, and other body parts. For instance, plasma, which is the liquid portion of blood, consists of 90% water.

The percentage in the lungs is 83%, in muscles and kidneys 79%, in the brain and the heart 73%, in the skin 64%, while bones are composed of 31% of water.

Water Storage at the Cellular Level

About two-thirds of the entire water amount in our bodies is in our cells, while the rest is in extracellular fluid. Let’s try to break down the difference between the two.

What Is Intracellular Water?

As the name suggests, intracellular water (ICW) is located within the cells. It comprises around one third of the entire body water, and its role is to transport molecules into different organelles.

ICW is rich in electrolyte potassium and low in electrolyte sodium. Moreover, it is a rich source of essential dissolved substances and proteins needed for all cellular processes.

What Is Extracellular Water?

Extracellular water (ECW) is found outside of your cells, and its main function is to deliver oxygen to them, clear waste from metabolic processes, and control electrolyte movement. It makes up the other two-thirds of the total body water in healthy adults, which is around 40%.

Unlike ICW, ECW is rich in electrolyte sodium and low in electrolyte potassium. It consists of transcellular fluid, blood plasma, and intestinal fluid.

Strive For Balance Between ICW and ECW

Balance is the key when it comes to the ICW and ECW ratio (it must be 3:2 in favor of the former). Your body will signal you if any of them goes out of balance.

Thus, if there is an increase in extra cellular water, you can experience inflammation, kidney failure, and obesity.

On the other hand, intracellular water amounts sometimes increase due to resistance training as the cells take in more water. This is a positive change and a sign of increased lean body mass, so you have nothing to worry about.

How Much Water Do I Need?

Glass of water

Your ideal body water percentage depends on multiple factors, including your age, hormones, and body composition. Aside from that, the water amount someone needs also depends on the situation they are in. For instance, you need more water during exercise, while you’re sick, and when you are in a hot environment.

Therefore, it is essential we drink around eight glasses of water per day, more or less. The recommended daily water intake is 3.7l for men and 2.7l for women, both over 19 years old. This amount increases during pregnancy when women should consume around 3l of water daily. While breastfeeding, their daily water intake should be even higher — 3.8l.

Calculate Your Water Body Percentage

Nowadays, you have online calculators that can help you find out your body water percentage. However, you can also use the Watson formula:

For men — TBW = 2.447 - (0.0914 x age) + (0.1074 x height) + (0.3362 x weight)
For women — TBW = -2.097 + (0.1069 x height) + (0.2466 x weight)

It’s worth noting that the measurements taken should be expressed in centimeters, liters, and kilograms.

This calculation is not 100% accurate, but it estimates your total body water percentage. It should serve as a guideline and tell you whether you are in a healthy range.

Body water percentage can also be calculated by using the dilution method and the BIA method, both of which must be conducted by trained physicians.

The former includes drinking deuterium oxide, also known as heavy water. Once it distributes around the body and settles, its amount is compared with that of normal water, and the proportion is your total body water.

The latter method involves a BIA device, which applies low electrical current to the body and measures these impulses. By calculating the difference in ECW and ICW, you get the balance between the two.

The Importance of Hydration

Staying hydrated is a vital part of maintaining good health. Studies show that over 75% of Americans are chronically dehydrated, which severely impacts protein production, increases the likelihood of injury, slows down blood flow, and causes muscle mass breakdown.

Drinking enough water:

Contributes to a healthier heart
Decreases joint pain
Speeds up weight loss and maintains water balance
Supplies your brain with oxygen and provides more energy
Improves brain performance
Helps with better temperature regulation
Detoxifies your body
Aids migraine pain

What Is a Healthy Water Percentage and How to Maintain It

Woman drinking water

As we mentioned, your body's water percentage changes as you age, and your body composition can also affect it. Therefore, the following percentages are merely averages.

It is recommended that adult women maintain a body water percentage between 40% and 60%. On the other hand, male adults typically have a body water percentage between 50% and 65% of their total body mass.

To maintain an optimal water body percentage, consider the food and beverages you consume daily. Drinking plain water is the safest option, but be careful with beverages like coffee, tea, alcohol, and soda because they have a diuretic effect.

Consume food with a high water percentage, such as watermelons, oranges, strawberries, and tomatoes. Green vegetables, like lettuce, spinach, and cucumbers, are also excellent water sources.

You can see how successful you are by the number of times you use the toilet — if you hydrate enough, your body will produce more urine in the kidneys, but if you don’t, your body will conserve water, and you won’t feel the need to go to the restroom.

Is It Possible to Consume Too Much Water?

Although it rarely happens, drinking too much water is possible, and it is known as water intoxication. In this condition, sodium levels drop too low and can lead to hyponatremia.

Drinking is not the only route that will lead you to water intoxication. Certain conditions, such as kidney disease, poorly managed diabetes, and congestive heart failure, can cause fluid retention in the body.

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Conclusion

As you now understand how vital water is for your body's proper functioning, you can check if you are meeting the daily dose and calculate its percentage using the Watson formula. If your numbers are low, start small and create a routine you can follow.

Incorporate high water content foods, healthy beverages, and a few more glasses of water per day. Listen to your body and look at the signs it gives you — if you have dry lips and experience frequent headaches, you should definitely increase your daily water intake.