Hypothermia & Cold Water Survival

Cold Water Kills

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Safety experts estimate that half of all drowning victims actually die from the fatal effects of cold water, or hypothermia, and not from water filled lungs. Loss of body heat is one of the greatest hazards to survival when you fall overboard, capsize, or jump into the water. Cold water robs the body of heat 25-30 times faster than air. When you lose enough body heat to make your temperature subnormal, you become hypothermic. Sudden immersion in cold water cools your skin and outer tissues very quickly . Within 10 or 15 minutes, your core body temperature (brain, spinal cord, heart, and lungs) begins to drop. your arms and legs become numb and
completely useless. You may lose consciousness and drown before your core temperature drops low enough to cause death.

Rules of 50

1 - An average adult person has a 50/50 chance of surviving a 50 yard swim in 50 degree F. water.
2 - A 50 year old person in 50 degree F water has a 50/50 chance of surviving for 50 minutes
 

Body Hot Spots

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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 to avoid hypothermia. The head and neck are the most critical areas. The sides of the chest and armpits, 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.

How Cold is "Cold Water"?
 

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Cold water does not have to be icy... it just has to be colder than you are to set water hypothermia in motion. A person who is wet, improperly dressed and intoxicated can become hypothermic in 70 degree F weather. The rate of body heat loss depends on water temperature, the protective clothing worn, percent body fat and other physical factors, and most importantly the way you conduct yourself in the water.

Note: Much of Alaska's waters are Very cold! Many of the larger bodies of water, rivers, and all marine waters are in the low 40s (Fahrenheit). Without a survival suit a person loses functional use of their limbs within minutes.

Unconsciousness soon follows.

Different activities in the water consume varying amounts of body heat. The more energy (heat) you expend, the quicker your body temperature drops,  reducing your survival time. As shown below wearing a life jacket (PFD) can add hours to your survival time.

Predicted Survival Time

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(average adult in 50 degree F (10 C) water)
 

How To Survive In Cold Water

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If you suddenly find yourself in the water don't panic! Calmly follow the procedure below to increase your survival time.

Minimize body heat loss. This is the single most important thing you should do. Take the following steps:

Do not remove clothing, despite what you may have been told. Instead , button, buckle, zip and tighten collars, cuffs, shoes and hoods. Cover your head if possible. A layer of water trapped inside your clothing will be slightly warmed by your body and help insulate you from the colder water, slowing your rate of body heat loss. Put on a PFD if available.

Devote all your efforts to getting out of the water. Act quickly before you lose full use of your hands and limbs. Climb onto a boat, raft, or anything floating. Right a capsized boat and climb in. Most boats will support you even if full of water. If you can not right a capsized boat climb on top of the hull. The object is to get as much of yourself out of the water as possible.

Do not attempt to swim unless it is to reach a nearby boat, another person, or a floating object on which you can climb or lean. 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. Heat Escape Lessening Position (H.E.L.P) hold knees to chest to protect trunk of body from heat loss. Wrap arms around legs and clasp hands together.

Huddle, huddling together with 2 or more people will extend survival time 50% longer than swimming or treading water.

Remain as still as possible, however painful. Intense shivering and severe pain are natural body reflexes in cold water which will not kill you but heat loss will.

First Aid For Hypothermia

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Any person pulled from cold water should be treated for hypothermia. 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.

Your goal in treating hypothermia is to prevent further body cooling. Severe cases call for re-warming by trained medical personnel. In all cases, arrange to have the victim transported to a medical facility immediately.

What To Do:

Gently move the victim to warm shelter. (Treat gently to prevent fibrillation of the heart)

Check breathing and heartbeat. In cases of hypothermia you should check very closely for as long as two minutes. Start CPR if necessary.

Remove victim's clothing with a minimum of movement, cut them away if necessary.
 

Lay victim in a level face up position with a blanket or other insulation beneath them.
 

Wrap victim in warm blankets, sleeping bag or other warm covering.
 

If there will be a long delay before victim arrives at a medical facility use the following re-warming techniques.

Apply heating pads or hot water bottles (wrapped in a towel to prevent burns) to the head , neck, chest, and groin.

Do not apply heat to arms and legs or give them a hot bath. This forces blood out through the cold extremities and back to the heart, lungs and brain, which will further drop the core temperature. This can cause "after drop" which can be fatal.
 

Do not massage or rub the victim, rough handling may cause cardiac arrest. Apply warmth by direct body to body contact. Have someone remove their own clothes and lay next to victim skin to skin. Wrap both in blankets.
 

f person is alert enough you can give them hot drinks. If they are unconscious or stuporous do not give them anything to drink. Never give alcoholic beverages.

Cold Water Drowning

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Some apparent drowning victims may look dead, but may actually still be alive! A phenomenon called the "mammalian dive-ing 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 re-warming and revival techniques. Most the waters of Alaska are cold enough at any time of year to trigger this reflex. People have been revived after having been submerged for extended periods, some in excess of 45 minutes! So don't give up.