The human body is 70% water. We are built of cells, which in our bodies is more than 50 trillion. Cells differ in their composition, function, size and life time. The process of dying and creating new cells is constant and necessary for our existence. Essential to the life of the cell is the continuous supply of nutrients and oxygen and the collection of toxins formed during the consumption of nutrients supplied. This is done through the water.
80% of our body cells are made of water, and only 20% of its volume is its proper structure. Water is present in every part of our body. Even the bones have water in their composition, because without it they would be fragile. It plays a special role as a filler in synovial fluid.
Water is a carrier of substances necessary for life and a binder. Without water there is no chance of any process taking place in our system. Constant fluid rotation is essential for life. When this process is unsettled, the problem immediately arises, illness, and if the cycle is not restored, death occurs.

Fluid rotation is very fast. Man has an average of about 5 liters of blood. Within an hour, almost 350 liters of life-giving liquid flows through the heart. Along with the blood, the necessary nutrients and oxygen are distributed to all body cells. The lymph that receives substances from the blood and transmits them to the cells creates a volume of about 12 liters. The water contained directly in the cells is the next 25 liters.

Our body is made up of cells, between which there are empty spaces through which tissue fluids flow with substances suspended in them. Cells use vital substances, and by-products of metabolism pass through the cell walls into the tissue fluid. Fluids flow only in one direction, without the possibility of reversing. The liquid penetrates into the bloodstream and is then filtered through the kidneys. In this way, we get rid of toxins. If we additionally use mineral water, the purification process will be strengthened. For example, the detoxifying effect of waters containing sulfur ions has been known for a long time. Ranier and Rabussier found in the experience with drinking sulfuric water on dogs the excretion of mercury in the urine.

Regardless of whether nutrients penetrate directly through the wall of the small intestine, or are subjected to additional treatment in the liver and other glands, the blood supplies them to the cells. Arteries and veins do not leak water. All substances transported through the blood pass through the walls of tiny capillaries, the surface of which is 6,000 m2. Blood returning to the blood contains side-products of the cells’ activity to be expelled. This happens at the same time that the total volume of blood does not change. Excessive escape of water from the blood to the cells is secured by the proper osmotic pressure, which is regulated by the presence of mineral salts. If the blood runs out of salt, then the osmotic pressure in the cells will be higher and the water from the bloodstream will penetrate into the fluid and then into the cells. This will direct the cells that will not function properly and create a shortage of intercellular fluid. If too much water leaves the blood, it may cause shock.
Blood is constantly filtered through the kidneys and unnecessary substances are excreted in the urine. Lack of filtration through the kidneys is dangerous for life. 180 liters of liquid flows through the kidney daily.

The blood contains substances that create the defenses of our body. This system is capable of immediate action by multiplying leukocytes, or white blood cells that fight infections.
Through the blood, hormones important for the functioning of cells are transported as chemical information carriers regulating their work. Coordination of chemical processes, regulation of the rate of consumption of nutrients and release of energy or excretion of water through the kidneys. The vasopressin hormone controls the regulation of renal water excretion to prevent the loss of too much of it. Due to the action of vasopressin, the currently required part of the water is absorbed back in the distal parts of the kidney tubules. Our system transmits and processes a huge amount of information. One of them is pain. The feeling of pain may indicate local chemical changes in areas around the nerves responsible for monitoring the acid-base balance. This mechanism prevents accumulation of acids that could damage the cell membranes and damage cells. When there is not enough water to flush out the excess acid products of nerve endings, they send this information to the brain through the sensation of pain. Unfortunately, indifferent to the signals given by the body, we simply take a painkiller instead of rehydrating the body.

Complementary to the circulatory system is the lymphatic system, which also distributes fluid throughout the body, closely cooperating with the circulatory system. However, this is much slower due to the lack of such a high pumping force, which is the heart for the circulatory system. The most important function of the lymphatic system is protection against infections. At various points, the lymphatic vessels connect to the lymph nodes. Limfa leaves the lymph node and takes lymphocytes and antibodies. In the case of some disease, the lymph nodes can be enlarged, because they have to deal with both the attacking organisms and the white blood cells destroyed by the disease, which need to produce more in danger.

So fluid exchange and movement are essential to life. To function properly, the body must constantly control the balance of liquids. The importance of maintaining a balance between the amount of water wasted and delivered to the body may be demonstrated by the fact that the loss of 1 or 2% is noticeable to the system and may negatively affect its functioning. Worse, during the course of evolution, man probably lost his ability to feel thirst.

Water is essential for the life of cells to be kept in the body needs potassium and sodium. Sodium keeps water in intercellular fluids, and potassium keeps water in the cells. They are a pair, as elements of a specific pump that pumps water into cells and from cells. In a simplified way, it can be said that sodium  is responsible for the absorption of water (moves between the cell membranes while transferring nutrients and removing toxins), and potassium for the maintenance of this water in the cells of the body. There must be an adequate balance between these two elements, it is a condition for effective hydration of the body. The most effective way to dehydrate is to drink a lot of water. In this situation, also sodium and potassium are leached out of the organism, i.e. the most important guards of the right water level in the cells. For this reason, it is recommended to drink slightly salted water to supplement sodium, potassium and prevent dehydration.

Most often there is no problem with sodium and potassium deficiency because they are present in virtually every food. Sodium overdose is manifested by excessive accumulation of water in the body, swelling of the body, problems with hypertension. If we have efficient kidneys, we can easily rinse the excess sodium by drinking clean water. The kidneys easily expel excess salt, restoring balance.

Paradoxically, dehydration can occur when we drink a large amount of clean water, eg distilled water. The body in the process of getting rid of excessive amounts of water released simultaneously sodium and potassium necessary to maintain water in tissues and body fluids. If we do not supplement the diet with the necessary amounts of sodium and potassium salts, our body will have a serious problem to maintain the vital functions of our body.
Body fluids have a content of 0.9% NaCl. The basis for drips administered intravenously in the hospital is from so-called saline, i.e. a solution of water and salt at a concentration of 0.9%. If we want to hydrate the body, we can drink water at this concentration, i.e. in a liter of water, we must dissolve 1 g of salt.