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Cold Water Immersion Kills

Proper response to accidents results from good training and common sense. If an injury is minor, treat it immediately. If an injury is major, make the victim as comfortable and safe as possible until medical personnel arrive, assuming you have a way to call for help.

Cold Water Immersion and Hypothermia

Cold water immersion kills in several ways. The colder the water, the greater the chance of death. However, the initial reaction to cold water immersion can occur in water as warm as 77° Fahrenheit. By understanding how your body reacts to cold water, you can prepare for and be better able to respond appropriately, thus increasing your chance of survival.

There are four stages of cold water immersion.

Stage 1: Initial “Cold Shock”

Initial "cold shock" occurs in the first 3-5 minutes of immersion in cold water. Sudden immersion into cold water can cause immediate, involuntary gasping; hyperventilation; panic; and vertigo—all of which can result in water inhalation and drowning. Immersion in cold water also can cause sudden changes in blood pressure, heart rate, and heart rhythm, which also can result in death.

Stage 2: Short-Term “Swim Failure”

Short-term "swim failure" occurs 3-30 minutes following immersion in cold water. The muscles and nerves in the arms and legs cool quickly. Manual dexterity, hand grip strength, and speed of movement all can drop by 60% - 80%. Even normally strong persons can lose the strength necessary to pull themselves out of the water or even to keep their head above water. Death occurs by drowning.

Stage 3: Long-Term Immersion Hypothermia

Long-term immersion hypothermia sets in after 30 minutes, at a rate depending on water temperature, clothing, body type, and your behavior in the water. Cold water robs the body of heat 25 times faster than cold air. Hypothermia occurs when your body loses heat faster than it produces it, cooling the organs in the core of your body. Hypothermia eventually leads to loss of consciousness and death, with or without drowning.

Stage 4: Post-Immersion Collapse

Post-immersion collapse occurs during or after rescue. Once rescued, after you have been immersed in cold water, you are still in danger from collapse of arterial blood pressure leading to cardiac arrest. Also, inhaled water can damage your lungs, and heart problems can develop as cold blood from your arms and legs is released into the core of your body.

Chart showing stages of cold water immersion
Symptoms of Hypothermia

Learn to recognize symptoms of hypothermia. They are listed here in order of severity.

  1. Shivering slurred speech, blurred vision
  2. Bluish lips and fingernails
  3. Loss of feeling in extremities
  4. Cold, bluish skin
  5. Confusion
  6. Dizziness
  7. Rigidity in extremities
  8. Unconsciousness
  9. Coma
  10. Death
Your Chance of Surviving a Cold Water Immersion

Your chance of surviving cold water immersion depends on having sufficient flotation to keep your head above water, controlling your breathing, having timely rescue by yourself or others, and retaining body heat.

Prepare for boating in cold water conditions by always wearing a secured life jacket. Also wear layered clothing for insulation. Equip your boat with a means for re-entry (ladder, sling, etc.) to use if you should fall into the water.