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Cold-water Immersion

Hypothermia happens when your body temperature drops below 95 degrees. Because your body can cool down 25 times faster in cold water than in cold air, you need to know what to do if you fall into the water. Remember, the water does not have to be exceptionally cold for someone to experience the effects of cold water immersion.

The best preventive measures against hypothermia include wearing your PFD and having communication and signaling devices attached. Preventing capsizing, swamping, and falls overboard are the ideal, but if any of these happen, having a ladder or some other means to re-enter the boat drastically increases your chances of survival.

Researchers (Golden and Harvey, 1981) identified four stages in which a person immersed in cold water may become incapacitated and die. Boaters who understand the physiology of cold water immersion and understand the decisions that should be made if someone does fall into the water have a greater chance of surviving if it happens.

Wear Your PFD

The best way to protect yourself against hypothermia is to wear your PFD. Not only will the extra layer help keep the warmer water trapped close to your body, it will also keep your head out of the water, which is the place you lose most of your body heat. In addition, you won't lose body heat from having to work to keep afloat, and the chances of inhaling water are reduced when you automatically gasp as your body hits the cold.

Wear Protective Clothing

A lot of boaters wear hats for protection from the sun, but they are also important for holding in body heat if you ever find yourself floating in cold water. If the impact of hitting the water knocks the hat off, put it back on if you can reach it.

You can also wear a neoprene wet suit and gloves to protect you against the effects of the cold water. Wearing protective clothing won't prevent hypothermia, but it will slow the effects down, hopefully long enough for you to get out of the water and into dry clothing.

Conserve Your Heat

Because you lose body heat so much faster in the water than in the air, try to pull yourself out of the water as far as possible. Climb on top of anything that floats.

If you cannot get your body out of the water, use the H.E.L.P position. As you saw in the picture in the previous section, you pull your knees into your chest, cross your feet, cross your arms over your chest, and float.

If anyone else is in the water with you and you are wearing your PFD, huddle together to share your body warmth.

Stages, Symptoms, and Treatment of Hypothermia

Hypothermia progresses from mild to severe. The time it takes to go from one stage to the next depends on the temperature of the water and the degree of protection the victim has against the cold.

Stage 1 — Initial Reaction

When first hitting the water, the victim automatically gasps and then starts breathing four to five times faster than usual. His blood pressure and heart rate both go up. Holding his breath is also more difficult. This stage normally lasts from 2 to 3 minutes, however, hyperventilation could last up to 10 minutes. Dying during this first stage is possible, especially if the victim is underwater when he automatically gasps or if he has a stroke, heart attack, or loss of consciousness and subsequently drowns.

The symptoms of Stage 1 are:

  • Feeling cold
  • Shivering violently
  • Slurred speech

If someone is suffering from Stage 1 hypothermia, get him immediate medical attention before anything else. If this is not possible:

  • Move him to a warm place
  • Remove his wet clothing
  • Give him warm non-caffeinated drinks (no alcohol)
  • Keep him warm for several hours

Stage 2 — Short-term Immersion and Swimming Failure

During Stage 2, (the first 30 minutes after cold-water immersion), a victim's breathing returns to normal and she starts shivering. Her body pulls the heat from her arms and legs to keep her core warmer. As a result, her muscles begin to fail and she can no longer swim. She should maintain the HELP position or hang onto the boat or other floating debris. Most people who are not wearing a PFD die from drowning during this stage, before their body reaches 95 degrees.
The symptoms of Stage 2 are:

  • Losing some muscle control
  • Feeling drowsy
  • Feeling exhausted

If someone is suffering from Stage 2 hypothermia, get her immediate medical attention before anything else. If this is not possible:

  • Move her to a warm place
  • Remove her wet clothing
  • Cover her with warm clothing and blankets

Stage 3 — Long-term Immersion

During Stage 3, (more than 30 minutes after cold-water immersion) the core temperature of the body falls below 95 degrees. The victim feels disoriented and starts acting irrationally. He might appear drunk or distant. He stops shivering when his core temperature drops below 91.4 degrees.
The symptoms of Stage 3 are:

  • Collapsing or losing consciousness
  • Having trouble breathing
  • Shivering decreasing or stopping
  • Appearing to be incoherent or irrational

Stage 4 — Post-rescue Collapse

If a victim has hypothermia when pulled from the water, she has an 80 percent chance of surviving. About 20 percent of immersion deaths occur during or within hours of the rescue. When pulled from the water, the heart has to work even harder as the cold blood from the arms and legs moves back into the warmer core of the body. Rescuers will try to lessen the effect by handling the body as gently as possible.

If someone is suffering from severe hypothermia:

  • Carefully take the victim from the water and maintain her position so that if she was floating horizontal, she should be kept horizontal. Moving her vertically could cause the blood to rush to other areas of the body and lead to a heart attack or stroke.
  • Do not to attempt to provide care. Do not touch or stimulate her arms or legs in any way.
  • Get her immediate medical attention.
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