Water is the major source of energy in the body. Dehydration causes the enzymatic activity of the body to slow down resulting in Tiredness and fatigue.
The blood is normally 92% water when you are completely hydrated, when dehydrated blood becomes thicker causing resistance to blood flow and resulting in elevated blood pressure.
When dehydrated your body will restrict airways as a means to conserve water. In fact the rate of histamine produced by the body increases exponentially as the body looses more and more water.
Dehydration impairs the elimination of toxins the skin and makes it more vulnerable to all types of skin disorders, including dermatitis and psoriasis, as well as premature aging and discoloration.