It is a warm day — you are on your
boat and get up to grab something. Suddenly you lose your balance and teeter off the side, falling into water that is less
than 15°C.
Your muscles are instantly paralyzed and there is no one around
to help you. You are experiencing cold shock. There is no time to figure things out.
Cold
water shock likely causes more deaths than hypothermia. Canada’s typically cold waters are especially dangerous if you
are unexpectedly immersed in them. For three to five minutes after sudden immersion you will gasp for breath. You could also
experience muscle spasms or a rise in your heart rate and blood pressure. Worse yet, you could choke on water or suffer a
heart attack or a stroke. Even strong swimmers can succumb to the effects of cold water shock.
Cold water can paralyze your muscles instantly. Trying to get a hold of a device while in the water, let alone putting
one on, will be nearly impossible because of the physiological changes your body will be experiencing.
A lifejacket or personal flotation device (PFD) will keep you afloat while you gain control
of breathing and prevent drowning from loss of muscle control. Sadly, many people do not understand this danger and how to
avoid it.
If you have survived the shock of cold water, hypothermia is the next
danger.
Hypothermia is a drop in core body temperature below the normal level
that occurs from a prolonged exposure to cold weather, particularly in watersoaked clothing or from direct immersion. At this
lower temperature a person’s muscle and mental functions are affected. Someone who is exposed to cold water, and becoming
hypothermic, can exhibit progressive signs and symptoms such as:
Shivering,
slurred speech and semi consciousness
Slow and weak pulse, slow respiration,
lack of coordination, irrational, confused and sleepy behaviour
Weak,
irregular or absent pulse or respiration
Loss of consciousness
If you end up in the water, do everything you can to conserve energy and
body heat. Swim only if you can join others or reach a safe haven. Do not swim to keep warm.
Extend your survival time by:
Wearing a Canadian-approved lifejacket
or PFD. Valuable energy will be lost keeping your head above water if you are
not wearing one. Climbing onto a nearby floating object to get as
much of your body out of or above the water as possible.
If possible,
adopt a heat escape lessening position: cross your arms tightly against your chest and draw your knees up close to them.
Huddle with others and make sure the sides of everyone’s chest are close together, with
arms around mid to lower back and legs intertwined.
Protect yourself
by wearing a lifejacket or PFD, multiple light layers of dry clothing and a
water or wind-proof outer layer. Other equipment that comes in a variety of styles and names, and provides additional protection
from hypothermia include:
Floater or survival suits: a full nose-to-toes
PFD Anti-exposure
worksuits: a PFD with a thermal protection rating Dry suits: to be used with a flotation device and a thermal liner
Wet suits: to be used with a flotation device, traps and heats water against the body
Immersion suits: to be used in extreme conditions when abandoning a vessel (usually for off-shore
use)
Knowing how your safety equipment works, especially in water,
is a good idea. Test it in a warm swimming pool or in calm water before you may have to use it in an emergency.
If there is warning your boat may be sinking, put on as much clothing as possible beneath
your lifejacket or PFD.
Survival in Cold Waters (2003) - TP 13822
Detailed information on cold shock, swimming failure and hypothermia
