Hypothermia is subnormal body temperature, a lowering of the body core temperature. When you lose enough body heat, you become hypothermic. Cold water robs the body of heat 25-30 times faster than air. Depending on the waters' temperature, 10 or 15 minutes, your core body temperature (brain, spinal cord, heart, and lungs) begins to drop. Your arms and legs become numb and useless. You may lose consciousness and drown before your core temperature drops low enough to cause death. Unconsciousness can occur when body core temperature drops from normal (98.6°F/37°C) to about 86°F/30°C. Safety experts estimate that half of all drowning victims die from the fatal effects of cold water, not from water filled lungs.
Hypothermia can be fatal and occurs in most survivors extracted from water under 68°F. Cold water does not have to be icy, just colder than you are to set water hypothermia in motion. A person who is wet, improperly dressed and intoxicated can become hypothermic in 70°F weather. The rate of body heat loss depends on water temperature, the clothing worn, percent body fat and other physical factors, and most importantly the way you conduct yourself in the water:
Predicted Survival Time (average adult in 50°F/10°C water)
Body Hot Spots
Certain areas of your body are "hot spots" that lose large amounts of heat faster than other areas. These hot spots need special protection against heat loss. The head and neck are the most critical areas. The sides of the chest, where there is little fat or muscle, are major areas of heat loss from the warm chest cavity. The groin region also loses large amounts of heat because major blood vessels are near the surface.
SURVIVING IN COLD WATER
DO NOT SWIM!!!
Unless it is to reach a nearby boat, another person, or a floating object on which you can climb. Unnecessary swimming "pumps" out warmed water between your body and your clothing circulating new cold water to take its place. Unnecessary movement of your arms and legs pumps warm blood to your extremities, where it cools quickly, reducing your survival time by as much as 50%!
If you can't get out of the water try one of the following survival techniques:
HYPOTHERMIA SYMPTOMS
Watch for the "Umbles." Stumbles, fumbles and grumbles. These may indicated the brain is being effected by cold being pumped through it.
Symptoms include intense shivering, loss of coordination, mental confusion, cold & blue (cyanotic) skin, especially around lips or fingers, weak pulse, irregular heartbeat and enlarged pupils. Once shivering stops, core body temperature begins to drop critically.
Core Body Temprature Loss
Mild . .-1°F Speech becomes slurred
-2°F Fingers become clumsy, nub, weak and shiver
Moderate . -3°F Feet loose strength, difficult to stand
-4°F The brain affected, thinking becomes difficult
Severe . . . -9°F Shivering is replaced by muscle rigidity
-14°F Unconsciousness and heart becomes irregular
-23°F Death from heart failure
Mild Hypothermia
Shivering, "goose bumps," hands may be numb with an inability to perform fine motor skills.
Moderate Hypothermia
Intense shivering, coordination is slow or labored with mild confusion. If the victim cannot walk 30 feet in a strait line he is moderately hypothermic. Later stages include persistent or violent shivering, slurred or difficult speech, dizziness or sluggish thinking or amnesia, fumbling or impaired gross motor movement and an inability to use hands, and irrational behavior or disinterest or depression.
Severe Hypothermia
Shivering may occur in waves with the pauses getting longer. Skin is blue or pale and puffy. Very little muscle coordination. Confusion, incoherent/irrational behavior (but the victim may LOOK aware). Muscle rigidity. Semiconsiousness, loss of awareness, pupils may have dilated. Decreased heart rate and heart fibrilation (victim may appear dead), then unconsciousness. By the time the core temprature is down to about 78°F and pulmonary edema, cardiac and repertory failure may occur but death can result before this happens. Death is imminent if breathing becomes shallow and erratic.
HYPOTHERMIA FIRST-AID
Any person pulled from cold water should be treated for hypothermia and ignore protests from the victim. Your goal in treating hypothermia is to prevent further body cooling. Severe cases call for rewarming by trained medical personnel. In all cases, arrange to have the victim transported to a medical facility immediately.
COLD WATER DROWNING
Some apparent drowning victims may look dead, but may actually still be alive! A phenomenon called the "mammalian diving reflex" can be triggered by cold water. This reflex, common to whales, porpoises and seals, shuts off blood circulation to most parts of the body except the heart, lungs and brain and slows the metabolic rate. What little oxygen remains in the blood is circulated where it is needed most. Do not assume that a person who is cyanotic and who has no detectable pulse or breathing is dead. Administer CPR and transport the victim to a medical facility as quickly as possible for specialized rewarming and revival techniques. People have been revived after having been submerged for extended periods, some in excess of 45 minutes! So DON'T GIVE UP!
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