The Body’s Water Needs

About two-thirds of the human body is water. So that we feel good, this proportion must be kept constant. This means that we each need take in 2 to 2.5 litres of water each day. On hot days or if you’re doing sport, your water needs can rise by a factor of three to four. Under normal conditions, we lose about 0.5 litres of water just by sweating through the skin alone. The same is true for breathing. We also excrete approximately 1.5 litres of water through the kidneys.

You can find out just why water is so important for us humans, and what happens if we do not keep our water balance in check here:

Water is vital...

... for our blood
As a key component of blood, water supplies us with oxygen and all the vital nutrients. At the same time, toxins are directed through the bloodstream to the kidneys and then excreted.

... for regulating the body temperature.
When the body temperature is higher, we sweat out water. Water retention is a symptom of fevers, and that’s why we feel sick.

... as a solvent
Water acts as a solvent and maintains body fluids’ consistency. For example, blood becomes thicker if there’s not enough water.

...for breaking down substances
Water plays a critical role in breaking down substances so that they can undergo further necessary processing. For example, the body can only use vitamins and sugar molecules by getting them through water.

... for cells and tissues
Water is an essential component of cells and tissues. 1,400 litres of bodily fluids flow through the brain alone each day, ensuring top performance and concentration.

Too little water in the body...

... results in thirst and makes the mouth dry.

... makes you weak. Just a two percent water loss affects your ability to think and concentrate.

... reduces the amount of harmful substances that can be excreted. Three percent less water results in reduced urine production.

... hurts. A five percent reduction means the heart has to use much more energy to pump thicker blood around the body. The resulting rise in body temperature leads to headaches and muscle pain. Also, perceptual ability decreases.

... means we can collapse. A ten percent loss in water means the body starts suffering from cramps. This results in a state of confusion, and there is a risk of kidney and circulatory failure.

Water also acts as...

... a calorie killer
water contains no calories, but it consumes them. A daily intake of one and a half to two litres results in an additional consumption of up to 100 kilocalories. That’s the equivalent of about ten minutes of jogging.
In this way, 36,500 additional calories can be consumed each year. That translates to approximately five kilograms of fatty tissue.
Tip: chilled drinking water also boosts energy consumption.

... a beauty elixir
Drinking water regularly reduces wrinkles. Water collects in the connective tissue and cushions small wrinkles naturally from the inside out.