High pressure is a natural reaction of the body to a large water shortage. The body adjusts its operation in such a way as to endure unfavorable conditions. When the total volume of fluid in the body decreases, the main blood vessels also reduce their light. This is because in the absence of such a regulation that adapts the capacity of blood vessels to the content of fluids, in vessels in the case of water shortage, an empty space would arise and gases would be emitted from the blood, which could cause blockages. When we do not drink enough water, some cells have to lose it for the sake of the circulatory system. When deficient, it is replenished in 66% from cellular water, 26% from extracellular water, and 8% from blood. When the amount of blood in the body decreases, the blood vessels have no way out – they must reduce their diameter to compensate for the loss of volume. This process begins by closing capillaries in less active areas. The missing water can only be replenished from outside or from another part of the body. When there is no water, closing the blood vessels is the only natural solution to keep the rest of the filled vessels.
With physical hypertension, physical activity is extremely important, because the more muscles work, the more capillaries open and maintain more blood volume as a reserve of the circulatory system. Hence, physical exercise is the best way to regulate people suffering from hypertension. This is one of the aspects of the physiology of hypertension. Capillaries must be open to avoid resistance to blood flow. Otherwise, only increased blood pressure (higher pressure) will be able to provide flow through the circulatory system.