REQUIREMENTS FOR MAINTENANCE OF HEALTH

To survive, you need water and food. You must also have and apply high
personal hygiene standards.
Water
Your body loses water through normal body processes (sweating, urinating,
and defecating). During average daily exertion when the atmospheric
temperature is 20 degrees Celsius (C) (68 degrees Fahrenheit),
the average adult loses and therefore requires 2 to 3 liters of water
daily. Other factors, such as heat exposure, cold exposure, intense
activity, high altitude, burns, or illness, can cause your body to lose
more water. You must replace this water.
Dehydration results from inadequate replacement of lost body fluids. It
decreases your efficiency and, if injured, increases your susceptibility to
severe shock. Consider the following results of body fluid loss:
A 5 percent loss of body fluids results in thirst, irritability, nausea,
and weakness.
A 10 percent loss results in dizziness, headache, inability to walk, and
a tingling sensation in the limbs.
A 15 percent loss results in dim vision, painful urination, swollen
tongue, deafness, and a numb feeling in the skin.
A loss greater than 15 percent of body fluids may result in death.
The most common signs and symptoms of dehydration are—
Dark urine with a very strong odor.
Low urine output.
Dark, sunken eyes.
Fatigue.
Emotional instability.
(BASIC SURVIVAL
MEDICINE)