How Much Water Is Enough

Survive on less water than you think

Paul G. Weir

Described by planetary explorers as a Goldilocks planet, our solitary blue dot is just the right distance away from the sun — not too far and not too close — so that water is present in liquid form on its surface. No other planet in our solar system has the traits necessary to hold water in liquid form; most are way too cold, such as Neptune and Uranus, while the inner planets, such as Mercury and Venus, are much too hot. However, Earth does this in a big way, as 70 percent of its surface is covered in liquid water, trillions and trillions of gallons of it. Without it, life on this planet would not be possible, as human beings are composed mostly of water, and we need it daily to livelife comfortably.

The big problem with the vast majority of the water on the planet is that it is not potable; only 3 percent of the water found in liquid form on this planet is drinkable. And most of that is in underground aquifers and inaccessible to humans, while the rest is saltwater. It is a terrible irony that the majority of people stranded in the great expanse of the world’s oceans after a plane crash or a boat catastrophe usually die from lack of water… not drowning or exhaustion or starvation.

DROUGHT AND DEHYDRATION

While a human can survive without food for three weeks or more, an individual can go without water for only a few days to a week, and that’s under ideal conditions. Add into the situation an increase in temperature, an increase in activity, and the level of salt in his or her diet (if any), and the level of liquid reserves in the body can be drastically reduced.

Only a 5 percent loss of bodily fluids causes a sensation of thirst. If the body is pressed further, that sensation turns into irritability, nausea and weakness. Double the loss to 10 percent, and the victim will experience dizziness, headache, inability to walk, and a tingling sensation in the limbs. A 15 percent loss of body fluids results in dim vision, painful urination, swollen tongue, deafness and a numb feeling in the skin.

The body compensates for the fluid loss by increasing the heart rate and constricting blood vessels to maintain blood pressure and flow to vital organs. Eventually, you’ll feel nausea, weakness and delirium. As you become more dehydrated, the brain and other organs receive less blood, which leads to coma, organ failure and eventually death.

SIGNS OF DEHYDRATION

The most common signs and symptoms of dehydration are dark urine with a very strong odor, darkened skin around the eyes, unusual fatigue, loss of skin elasticity, and a deep line down center of the tongue. It goes without saying that the victim will feel thirsty, but beyond that and the aforementioned sensations, symptoms may coincide with other heat-related ailments, such as heat cramps (muscle cramps due to loss of salt in the body), heat exhaustion (headache, confusion, dizziness, excessive sweating), and heat stroke (lack of sweating, quick pulse, nausea, unconsciousness).

COMBATING DEHYDRATION

Your body's normal temperature is 98.6 degrees (F). Your body gets rid of excess heat by sweating. The warmer your body becomes — whether caused by work, exercise, or air temperature — the more you sweat. The more you sweat, the more moisture you lose. Sweating is the principal cause of water loss and one of your biggest enemies if you are dehydrated. However, if you stop sweating during periods of high air temperature and heavy work or exercise, you can quickly develop a heat-related injury.