Written by: Bob Salo
The term “Cold Water Immersion” refers to sudden immersion of a body in water that is less than about 50° F or 10° Centigrade. BC waters, especially off the west coast of Vancouver Island seldom get to this temperature.
The term “Hypothermia” refers to the lowering of core body temperature over a long period of time.
Unlike hypothermia, the effects of cold water immersion can lead to death in just a few minutes and in some cases, instantly. Sudden entry into the water can cause cardiac arrest, even for people in good health. The shock of the cold water can also cause an involuntary gasp reflex that can cause victims to inhale water and drown. After just a few minutes, the ability to swim or tread water is impaired as the victim loses muscular coordination.
It is impossible to die from hypothermia in cold water unless you are wearing flotation, because without flotation – you won’t live long enough to become hypothermic!
True hypothermia usually doesn't set in until at least 30 minutes after being in the water, depending on body size and type, insulation of clothing and other factors. Even then, victims wearing a PFD can survive for hours before losing consciousness and drowning.
Three Stages of Cold Water Immersion
Stage 1 -Cold Water Shock
When someone falls into cold water their first uncontrollable response is to take a large breath of air, called the "involuntary gasp reflex." If their face is in the water when that gasp occurs, then their chances of survival immediately diminish. Of all the people who die in cold water, it is estimated that 20% die in the first two minutes! They drown, panic, or have heart problems – all from the initial shock.
Stage 2 -Swim Failure or Cold Incapacitation
After one has been in cold water for up to 30 minutes, there's a continued inability to hold one's breath, loss of coordination in the arms and legs results in cramping and inability to grab onto anything. Swimming becomes increasingly difficult, and painful. You are still not at the Hypothermia stage, but are at the stage of potentially not being successful performing a self-rescue! Without ever experiencing a drop in core temperature, over 50% of people who die in cold water, die drowning from Cold Incapacitation.
Stage 3 -Hypothermia
Depending upon an individual’s health, fitness and thermal protection it can take from 30 minutes to 1 hour or more to reach this stage. The first signs are uncontrolled shivering and the person starts to become disoriented. As the body pulls blood away from the extremities toward the organs, the person usually cannot use their arms and legs for self-rescue. When severe hypothermia sets in, they will eventually become unconscious. A person's normal body temperature is around 98.6° F. Most people cannot survive a core body temperature below 85° F.
How does this information relate to kayaking in BC?
Ocean water on the BC coast, even in summer, is cold and can lead to dangerous problems with Cold Water Immersion and Hypothermia. Be prepared at all times when you go out for a paddle
- Thermal protection – wet suit or dry suit – should be worn at all times.
- A dry bag with warm fleece clothing - pants, top, gloves, hat, socks – should be part of every kayaker's Safety gear.
- Good skills at self-rescue, assisted-rescue and kayak rolling will minimize the time in cold water, leading to less chance of Cold Water Immersion and/or Hypothermia problems.
- Group Safety! Watch for signs and symptoms of hypothermia in your paddle companions. Ie; shivering, lack of co-ordination and diminished mental/physical abilities.
Information for this article is mainly from two sources:
- Jeffrey Pollinger U.S. Coast Guard www.oregon.gov/osmb