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Hypothermia & the Importance of Correct
Clothing
Many
cold-water drownings are perhaps mistakenly attributed to hypothermia. It seems
more likely that many of these drowning victims (primarily those without
Buoyancy Aids) never had a chance to experience hypothermia because of the
sudden and severely debilitating effects of cold water immersion. Of course,
when a dinghy sailor's ability to think clearly, or move effectively, is
impaired due to hypothermia, it can ultimately lead to an accident.
Hypothermia
is a condition that occurs due to the lowering of the body's core temperature.
If your body becomes so cold that it can no longer produce more heat than it
loses, you are becoming a victim of hypothermia.. It often happens so slowly
that you don't realize you're in danger. That's why it's important to be able to
recognize the early signs. If untreated, hypothermia can lead to death.
Hypothermia
most often affects dinghy sailors that have fallen into water. However, they can
also experience hypothermia due to a variety of other factors that can cause or
contribute to it's effects. Some of these include: improper clothing, wind
chill, getting wet from splashes or rain, and low energy reserves.
What causes hypothermia?
Cold,
wind, poorly insulated or wet clothing, immersion in cold water (also prolonged
immersion in warmer water), and fatigue are some of the main factors that can
contribute to hypothermia.
- Cold is the most common cause of hypothermia.
Chilled air cools down the body. You can also become hypothermic at
temperatures above freezing if you are exposed to a combination of factors
such as a cold wind along with wet clothing.
- Wind removes the thin insulating layer of
warm air next to the skin, a layer that is usually kept there by clothing.
Wind causes cooling or "wind chill." The stronger the wind at a
given temperature, the cooler the wind chill will be. Your head, the sides
of your chest, and your groin are areas of your body that are often
especially vulnerable.
- You can become exposed to extreme cold if
your clothing becomes wet or is not properly insulated to protect you
from the cold and wind. Clothing that is wet from sweat or precipitation
also speeds up the heat loss from the body. Properly insulated head gear is
also vitally important. In some instances, up to 50 percent of your
body's heat loss can be caused by an unprotected or poorly protected head.
- Cold water immersion speeds
up the process of cooling down the body. When you are in the water, heat is
conducted away from the body 25 times faster than in cold air.
- Fatigue will increase your
vulnerability to the risk of hypothermia.
The symptoms of
hypothermia include:
- Shivering
- Impaired coordination or motor skills
- Slurred speech
- Confusion or apathy
- Drowsiness or exhaustion
Hypothermia
can progress very rapidly from the onset of symptoms. Perhaps one of the most
problematic effects of hypothermia is the resulting confusion, or inability to
think clearly, that a victim can experience. Often a victim of hypothermia will
become immobile - both physically and mentally - and do nothing to help reverse
the condition.
Prevention
The
basic principle for preventing hypothermia on land or water is to stay warm and
dry maintaining body core temperature, ie. reducing body heat loss as
effectively as possible.
One of
the best ways to do this is to dress for the conditions.
Guidelines
that work
Drysuits
are excellent.
They reduce the wind chill
They allow thin layers to be worn under the drysuit, eg polar suit, thermal
underwear – providing insulation to all areas of the body, especially the high
heat-loss areas: neck, armpits, sides of chest and groin. The first layer of
clothing should allow the skin to breathe by allowing sweat to escape.
Underwear, socks, made of polypropylene or knitted silk allow sweat to escape
from next to the skin.
They keep the wearer dry, allowing no wet clothing
And if the suit is semi of fully breathable they will allow perspiration to
evaporate, so a person does not get wet and cold from their own sweat.
Wetsuits
will work to a degree but
they need an extra cover to reduce the wind chill as the neoprene is tight on to
the skin (if it fits correctly – NB if it doesn’t the wearer is liable to
increased risk of cold water immersion – see GASP article )– with no thin
layer of air around the body.
they do not breathe and perspiration can cause the body to cool
Wear
warm head covering. Most body heat is lost through the head
Protect
your feet and hands.
Neoprene winter gloves definitely reduce the wind chill on the back of your
hands and provide insulation, the amara and leather gloves however once wet will
have a worse cooling effect than no gloves at all since the evaporation of water
will continue to chill the hands.
Feet kept dry and insulated will have least heat loss, ie wearing thermal socks
in a drysuit with socks inside dinghy sailing boots.
Respiration:
Heat escapes when air is exhaled. This can be reduced by covering the mouth and
nose area with wool or a bandana
Other
factors to take into account
Pace
yourself during vigorous activity. Take regular breaks to get away from the cold
environment. Don't let yourself become weakened through fatigue. People who are
fit are less prone to hypothermia. Stay fit through physical conditioning.
Be
sure you have some form of flotation before you enter the water. Without flotation, even good swimmers will have
difficulty staying afloat in cold water.
Avoid
alcohol.
Even small amounts of alcohol increase body cooling
What To Do
If
The Situation Arises
Once
the symptoms of hypothermia are present, swift action is required to help
correct the situation. If a sailor is in the water and getting out of the water
is an option, do so. Do not swim any distance since valuable energy reserves
could be spent. Also, the movement of cold water around a person's body will
accelerate heat loss. If possible, re-enter or get on top of a capsized boat. If
stranded in open water conserve body energy and lessen heat loss rate by
huddling with other , or if alone curl knees to the chest and lock arms around
them.
When
out of the water remove wet clothing. Keeping wet clothing on is worse that
being naked since the evaporation of water will continue to chill the body. Get
dry and stay dry. Get out of the wind. Get into dry clothing, under a blanket.
Preventing the loss of body heat is critical, and to aid raising the body
temperature by drinking small amounts hot liquids, warming body areas such as
the crotch and under the arms anywhere the main arteries are close to the
surface of the skin, this will hasten recovery with emergency heat – packs
sharing body heat with others, . Do not rub the body and do not stop the
shivering.
If
the patient is semi-conscious or worse: Try to keep him/her awake. (Do not give
hot liquids by mouth.) Leave him/her stripped. Put him/her in a sleeping
bag/blanket with another person (also stripped) to transfer heat. If you can put
the victim between two donors, skin to skin contact is very effective treatment.
Transport
the victim as soon as possible to the closest hospital for monitoring. It takes
a very long time to warm the inner core and only a rectal hypothermia
thermometer is long enough to find out what the inner core temperature really
is. DON'T DELAY!
Hypothermia
is a serious life-threatening condition that can happen rapidly and requires
immediate attention. Hypothermia victims that suffer more than just mild effects
should seek emergency medical attention immediately.
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