Sunstroke is a dangerous condition that occurs when the
body’s thermostat breaks down from overheating. It can, and should always be
prevented, as even with treatment it may be fatal or cause permanent damage.
Although we are all used to thinking of this extremely
serious heat disorder as something that only happens to people who stay out too
long in the hot sun, in fact the heat itself is the problem and not the sun’s
rays. For instance, people who find themselves in very hot places such as
engine rooms and steel works can suffer the severe effects of ‘sunstroke’
without ever being near the sun. And, for this reason, doctors tend to talk
about ‘heat-stroke’.
The body’s reaction to heat
The body has two main mechanisms for losing heat. First, the
blood vessels to the skin are dilated so that more blood flows to the surface,
allowing it to lose heat through the skin into the air. Second, the skin is
cooled by the action of the sweat glands. The sweat glands pour out their salty
fluid on to the surface of the skin. It evaporates, and heat is lost as vapor.
Overheating
There are many ways in which the environment can intensify
the effects of the heat on the body - it is not just a question of the reading
on the thermometer. If the air is humid, then this reduces the ease with which
the sweat evaporates, so that it becomes more difficult to lose heat.
Similarly, if the air is very still, then less heat is lost from the surface of
the body by convection. People doing hard physical work in a hot environment
are, of course, producing a lot of heat of their own. They may be losing up to
one liter of sweat every hour, compared with the one liter per day of sedentary
workers in a temperate climate. This loss of salt and water can contribute to a
condition known as heat exhaustion, which, unless checked, can lead to the
eventual breakdown of the body’s temperature-regulating mechanism (heat stroke).
Fortunately, however, as the body gets used to working in a hot environment, it
adapts and the loss of salts decreases, making the body less vulnerable to heat
disorders.
Extra risk factors
The very young and the very old are most at risk from heat
disorders, and consequently from heat stroke. This is because their bodies’
temperature regulating mechanisms are not very efficient. Also elderly people tend
to wear too much clothing in hot weather.
However, there are several other pre-disposing factors.
People who are unused to heat, who are very overweight, who drink heavily, or
who are suffering from a feverish illness, in the right circumstances, may all
be at a greater risk from heat stroke.
Symptoms and dangers
The three basic signs of heat-stroke are: a very high
temperature (more than 41 ⁰C (106 ⁰F); a total absence of sweating; and,
most seriously, nervous system problems which may lead to coma. Disturbances of
mood, disorientation and headache, often accompanied by dizziness and
difficulty in walking all happen in the early stages of the stroke until,
eventually, consciousness is lost.
Unfortunately, a fully developed heat stroke is an extremely
dangerous condition and over 20 per cent of sufferers may die, even with
treatment. In addition, those who do recover may have persistent trouble in the
nervous system and their balance and co-ordination may take months to get back
to normal. However, if treatment is prompt - at the first sign of symptoms and
before consciousness is lost – then the chances of recovery are good.
Treatment and prevention
As soon as any symptoms appear, it is essential to call a
doctor immediately. Meanwhile, cool the patient down as quickly as possible.
The temperature should be brought down to about 39 ⁰C (102 ⁰F) - no lower as the patient’s
circulation may go into shock. The best way to cool the patient down is in a
bath of cold water. In hospital, special slatted beds on which sufferers can be
doused with water and cooled by fans are used. The most sensible and effective
way to fight sunstroke is, of course, prevention.
And this can be done quite simply by ensuring that the body
is not overheated. This means not staying out too long in the sun; wearing
cool, loose clothing in the heat; taking salt tablets and drinking plenty of
liquids when doing physical work in very hot environments.
