Water Balance

We need water to live.  In fact, 65% of our weight originates from nothing but water.  

Water makes up the largest component of blood.  Water carries the heat necessary for thermoregulation; water removes wastes from the body; water lubricates organs and joints; and water provides the necessary environment for all the body's chemical reactions.  Therefore, to function properly, the body needs to continuously maintain proper water levels.  Survivors accomplish this by focusing on replacing their water losses with similar water gains to maintain balance.

Under normal conditions, an average person loses approximately 1.5 liters of water per day (for our discussion, quarts and liters fill up approximately the same volume).  Specifically, our bodies lose about 0.5 liters through the skin, about 0.5 liters through the lungs, and about 0.5 through urine every day.  Conversely, our body usually gains around 0.5 liters from the metabolism of food leaving us with a normal drinking requirement of about 1.0 liter of water per day.

Environmental conditions, level of activity, diet, or illness can affect the water balance in our body.  Hot environments pull water from our body via sweat.  Add in exercise, and we can lose up to two liters of water per hour.  Additionally, very cold dry environments pull as much as 2 liters of water per day from our bodies simply through breathing.  Protein-rich foods extract water from the body as well.  Urea, a toxic by-product of protein metabolism, requires additional urine production in order to be expelled from the body.  Illnesses causing vomiting or diarrhea speed up water losses, threatening the balance even more.  Any of these factors easily tip us into a water deficit (or dehydration) unless we replenish the lost water immediately.   

   

Under normal circumstances, we simply replenish the water by drinking more.  Problems arise, however, if the water deficit occurs when a natural disaster, emergency, or accident at sea prevents ready access to safe drinkable water.  Therefore, it is critical to plan and prepare for our water needs before a crisis hits.