To best define dehydration in mammals, first consider what is hydration.
When a body is properly hydrated, the fluids both inside and out the cells are in balance and at optimal levels.
Each tissue, organ and cell in the body must have water in order to function properly. Your body relies on water to maintain body temperature, lubricate your joints and remove waste materials. For good health, it is important to keep your body well hydrated.
The organs, tissues and down to every cell, we need water to function properly.
Water helps lubricate, remove waste, and maintain temperature and maintain blood pressure.
Based on what it does, we like to use the definition of dehydration as a drought inside our bodies.
The easiest way to tell if you are are properly hydrated is the urine test. If your urine is almost colorless or pale yellow, you are most likely well-hydrated. One exception to the urine test is urine after certain foods and supplements, which may be darker or of a different color.
Other indications of proper hydration is mental alertness, increased energy, free of headache or mental confusion, and the eyes tearing properly.
Dehydration is when our bodies are in a state of less than optimal hydration or fluid levels.
Unlike having water in a jar or container where you can measure how much you have, our bodies are the vessel. The water in our bodies is inside our trillion cells and outside those same cells. Think of our bodies as being made up of trillions of microscopic drops of water inside our cells and a thin layer of water outside our cells.
Now think of the cells like grapes. When there is not enough water inside, they shrivel up. When there is not enough water outside, there is a drying and loss of lubrication and elasticity.
When we enter into dehydration, our bodies use a complex system that both balances the water reserves and makes sure the most important organs have enough water to survive.
In this dehydrated state, the water goes from the organs that can survive with the least water to the ones that require the most water.
This is where dis-ease gets started, in various organs depending on our genetic make up, diet and life stye.