Cold water shock
Kayakers have been found dead hanging upside down in their kayaks, having apparently made no attempt to even exit their boats. Most kayak deaths are listed as drownings. It was thought that these victims drowned because of hypothermia. Recent speculation is that many of these drowning victims may actually be victims of Cold Water Shock, a sudden and deadly result of a quick plunge into cold water.
Plunging your torso, head and neck into cold water ( <10 degrees
C) can lead to a number of deadly debilitating physical
reactions that can lead to immediate death. The colder the
water, the more likely cold shock may affect you. Without a PFD
on when you go over, you will not survive if cold shock occurs.
Many PFDs typically worn by kayak paddlers will not save you
either.
When your body is quickly immersed in cold water, it reacts with
a sudden constriction of the capillaries under the fat just
under your skin. This causes a sudden increase in blood
pressure. Your heart rate rises dramatically, perhaps to its
maximum. These are automatic physical reactions and can not be
consciously controlled. The following can happen:
1. Immediate loss of consciousness. Without a PFD that will
right your body and float your nose and mouth out of the water,
or immediate assistance, you will drown. Most PFDs worn by
paddlers will not right an unconscious body.
2. Cardiac arrest from the strain placed on your heart. If your
heart can not stand the sudden jump to maximum heart rate and
the high blood pressure, it stops. Without immediate assistance,
you are dead.
3. Involuntary Gasping Reflex (Mammalian Dive Reflex) can cause
you to inhale while you are underwater. You will not be able to
prevent this reflex reaction. Cold water in the lungs or muscle
contractions of the windpipe may prevent you from breathing
should you regain the surface. If you hit your roll or wet exit
wearing your PFD, you PFD will bring you back or keep you at the
surface. Perhaps you live. No PFD, straight to the bottom with
you.
4. After gasping in a lung full of cold water, the temperature
of you heart plunges, the muscles stop contracting and you die.
Even if you manage to gain the surface or even land, you may
still die if you can not empty your lungs quickly enough.
So how do you prevent cold shock?
1. Only paddle in warm water. Not a realistic option for most
paddlers.
2. Wear protective clothing - a neoprene wet suit or dry suit
will protect the torso from the immediate effects of the cold
water and reduce the possibility of cold shock. However, most
paddlers still leave the head and neck areas exposed. Wearing a
neoprene hood that covers the neck and head will greatly reduce
the possibility of cold shock.
3. Practice - immerse yourself in cold water in safe conditions
with someone to rescue you if you need it. Tolerance can be
built up. However, you can never be sure how your body will
react each time, particularly regarding cardiac arrest. Practice
can be dangerous in and of itself. Make sure that your rescuer
knows what needs to be done if you fall victim to cold shock.
Start small by taking cool showers and progress to cold showers.
Consult your physician before attempting any of this.
When the water is cold, never paddle by yourself. If you are a
cold shock victim while paddling alone you will die.
Remember it is the temperature of the WATER, not the air that
matters. In fact if the air is warm while the water is cold, the
possibility of cold shock is even higher as the warm skin and
dilated capillaries are plunged into cold water. The greater the
difference between air and water temperatures, the more likely
cold shock will occur. Spring is the most likely season for Cold
Shock accidents as the warm air temperatures encourage kayakers
to dress for the air temperature and not the water temperature.
The more fit your are, with a lower body fat content, the more
susceptible your are to cold shock.
