A condition which is a threat to anyone out on Scotland's hills,exposure
to wet, cold conditions coupled with exhaustion can lead to the onset of
hypothermia. This is a condition which arises when the body core is cooled.
However, cold alone rarely kills. rather it is the combination of exhaustion,
cold, anxiety and mental stress which can be lethal, particularly (but
not exclusively) in winter.
It is a condition brought on by extended exposure
to the cold. Specifically, hypothermic symptoms can occur when the body's
core temperature drops below 35º C. The core body temperature is basically
the temperature of the torso. Such a fall will decrease the ability of
the body to manage normal muscular and cerebral functions.
The two most
common causes of hypothermia on the hill are exhaustion and injury. Walkers
with inadequate food, clothing and shelter will not be able to sustain
the level of physical work to replace the heat they are losing. Injury
leads to immobility and a similar inability to generate heat . The insulation
properties of most clothing are also severely reduced when wet and ,therefore,
dealing with wet clothing is a critical part of raising temperature or
preventing hypothermia. There are modern artificial down fillings that
maintain much of their insulating properties when wet and individuals who
regularly put themselves at risk through winter activities may wish to
pay for this added protection.
The signs and stages of Hypothermia
Signs of hypothermia will make themselves obvious when the body temperature
falls too far. . The signs become more pronounced the more severe is the
hypothermia;
- Mild hypothermia is manifest by shivering and impaired ability to perform
simple tasks, it may be accompanied by a reduction in the perception
of risk and the decision to sit down and take a rest. This is the time
to add a layer or to seek shelter from the wind. The classic test is
whether the individual can still perform mental tasks of a relatively
simple nature, (for example counting backwards from 103 by seven, 96.89.82
etc.).
- Moderate hypothermia is characterised by feeling bitterly cold and
stiff; stumbling shamblolic movement; judgement becomes severely affected
and mental confusion sets in; the victim shivering even when on move,and
shivering becomes uncontrollable; this is often accompanied by disregard
for self preservation (and failure to fasten clothing against the cold;
vision may becomeimpaired. By this stage the victim is usually beyond
self diagnosis
- Severe hypothermia brings shivering which has ceased to be constant,
but now comes in waves, muscles become rigid, pupils dilate, pulse rate
drops and finally collapse.At this stage that the hill walker is in real
trouble. It is at this stage that the victim needs to be off the mountain
receiving professional help and will need specialist heat immersion equipment
a mountain rescue crew might have to begin to recover on the hill
- At the final stage the body shuts down completely and is incapable
of reversing the process
What to do
If you spot any of the symptoms in someone else(you will not spot them
in yourself, because of the effect hypothermia has on your mental functions)
it is very important to act fast. If you are relatively near civilisation,
descend quickly to where you can get help. Watch the sufferer carefully,
they may behave irrationally and in self harming ways, deciding to wander
off, or more probably lie down. If a source of help is not near by, you
must treat the symptoms yourself quickly. First and foremost:
- Reduce heat loss. Give the sufferer any spare clothes you might have,
or swap wet clothes they are wearing for dry if you have any. Wet clothes
will draw heat away from the body more rapidly. Find some shelter from
the wind, but once there don't let the sufferer lie down. Move them about,
exercise will keep them warm. Use your space blanket or bivvy bag to
insulate them from the wind and your mat to insulate them from the ground..
- Add fuel and fluids. If you are carrying a flask of hot drink use that,ut
avoid alchohol and caffiene.Both will tend to increase dehydration and
hence componud heat loss.Carbohydrates are the most appropriate source
of energy and offer the quickest conversion of food to heat.
- Add heat. The most likely ways you will be able to do this is by creating
a snowhole, your emergency shetler and using the enclosure to trap and
retain heat. The more people in the shelter or bivvy bag the quicker
the warm will build up, so get in the bivvy bag too and share your warmth
How to avoid hypothermia
Far better than reacting to the symptoms is taking some preventative action.
It is never easy to predict weather conditions or the possibility of injury
which might result in the onset of hypothermia, but you can prepare for
it. :
- Eat a good breakfast before you head out, with lots of carbohydrates.
Fat is also good, since it offers a long, slow source of heat production.
- Don't go walking in the cold with a hangover.
- Take more food than you think you will need. A good way to stave of
hypothermia is to constantly top up your energy by eating. You could
take a flask of hot juice or some similar liquid, although they will
probably have lost their heat if you are caught out by accident or navigation
error and are on the hill later than planned.
- Wear the right clothes and carry spare layers in waterproof bags. Hats
and gloves are particularly important. The heat loss through the top
of the head is disproportionate to its size.
- Bring a survival bag. If the worst comes to the worst this is a light
and simple way of getting warm quickly.
- In winter, never walk alone far from shelter and easy escape routes,
unless your have equipped your self for extreme survival conditions.
Links
http://www.mountaineering-scotland.org.uk/leaflets/hypotherm.html
http://scotclimb.org.uk/safety/hypothermia.shtml
http://www.northern.police.uk/areas/lochaber_hills/tregaskis.htm
Body
mechanisms behind Hypothermia
This site goes into the physiology of hypothermia and is not primarily
a how to spot and how to treat primer. The first three offer this sort
of advice and and are similar to this page, but may well contain extra
information
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© Copyright Edinburgh Ski Touring Club 2007. e-mail: webman@estc.org.uk Last updated May 2007