Since the body continually loses water – 2.5 to 3 litres per day – through normal body functions, this water needs to be replaced to keep the body healthy. Ironically, the sensation of thirst occurs only after the body has started to become dehydrated. For this reason it is very important to drink water often, without waiting to feel thirsty. By the time you begin to feel thirsty, the body is already dehydrated to a level of 0.8% to 2% of body weight.
Here are just a few of the many important roles water plays in the functions of the body:
Your brain tissue consists of 85% water. When you are not properly hydrated it may be your brain that starts to feel the effects, with headaches, poor concentration and reduced short-term memory. Even your ability to perform arithmetic and the rapidity of your psychomotor skills can be reduced. This is due to the fact that dehydration causes the level of energy production in the brain to decrease. Studies have shown that a person’s ability to concentrate progressively declines when the body is subject to a water deficiency of just 1 to 2%.
Your blood is 95% water, which is what carries the essential nutrients to the cells in your body, and removes the waste from the cells. If you are dehydrated the mechanisms that regulate blood pressure will not work, which may cause an increase in blood pressure.
The skin is the largest human organ, both by weight and by surface area, consisting of 70% water. We lose a percentage of our body’s water everyday by evaporation through the skin. The environment in which we work, with climate-controlled heating and air conditioning, low humidity, and even simple things like soap and cleaning solutions can damage the protective outer layer of the skin, reducing its ability to hold moisture. When you are not drinking enough to compensate the for the body’ water loss, you may notice your skin feeling dry; moisturizers or body lotions can treat the symptoms, however the best solution is to reach for a glass of water and moisturize from the inside.
Every cell in your body depends on water to keep it working properly. The average person is made up of between 50 to 75% water, two-thirds of which is carried in the cells. If there is not enough water in the body these cells cannot effectively do the job that they are supposed to do, such as transport nutrients and eliminate waste.
Even your bones have a high level of water in them – approximately 22%. Water is also necessary to ensure the smooth movement of bone joints. The cartilaginous tissue at the end of the bones retains water to lubricate the movement of your joints. When well hydrated the two opposing surfaces slide smoothly; if the cartilage is dehydrated, the damage from friction increases, causing deterioration of the joints and leading to pain, such as arthritis.
The heart consists of 77% water. Clinical studies have shown that adequate hydration may improve the way your heart works and reduce your risk of developing heart disease.
The kidneys are made of 80% water. Their function is to remove waste products from the body, which are dissolved in water. When there is not enough water these waste products are not removed effectively which can cause damage to the kidneys. The National Kidney Research Foundation recommends that drinking two litres of water a day can reduce your risk of developing kidney stones.
The Liver consists of 73% water. Its function is to convert the body’s fat into energy it can use. But if the liver is forced to help in the work of the kidneys due to insufficient water consumption, the body will accumulate extra fat that would have been burned if there had been adequate water intake.
As counter-intuitive as it may sound, your body needs water to breathe: the lungs consist of 85% water. In order to take in oxygen and eliminate carbon dioxide, our lungs must be continually moistened with water. The average person looses between half to one litre of water per day just by breathing. When the body is dehydrated it tries to prevent respiratory water loss by producing histamines which close off the capillaries in the lungs. This reduces water loss, but makes breathing more difficult.