EFFECTS OF EXPOSURE TO HEAT
Effects of exposure to heat are:
1. Heat exhaustion
2. Dehydration exhaustion
3. Heat cramps
4. Heatstroke (sunstroke).
HEAT EXHAUSTION
Heat exhaustion is the body’s response
to excess loss of water and salt through sweat, caused by exposure to hot
environmental conditions. In fact, it is the warning that body is getting too
hot. Heat exhaustion results in loss of consciousness and collapse. Before the
loss of consciousness, following warning signs appear in the body:
i. Increased heart rate
ii. Increased cardiac output
iii. Dilatation of cutaneous blood
vessels
iv. Increased moisture of the body
v. Fall in blood pressure
vi. Weakness and uneasiness
vii. Mild dyspnea.
DEHYDRATION EXHAUSTION
Prolonged exposure to heat results in dehydration.
It is due to excessive sweating. Dehydration leads to fall in cardiac output
and blood pressure. Collapse occurs if treatment is not given immediately.
HEAT CRAMPS
Severe painful cramps occur due to
reduction in the quantity of salts and water as a result of increased
sweating, during continuous exposure
to heat.
HEATSTROKE –
SUNSTROKE
Heatstroke
Heatstroke is an abnormal type of hyperthermia that occurs during
exposure to extreme heat. It is
characterized by increase in body
temperature above 41°C (106°F), accompanied by some physical and
neurological symptoms. Compared to
other effects of exposure to heat such as heat exhaustion and heat
cramps, heatstroke is very severe and
often becomes fatal if not treated immediately. Hypothalamus loses the power of
regulating body temperature.
Sunstroke
Sunstroke is the hyperthermia caused
by prolonged exposure to sun during summer in desert or tropical
areas.
Persons Susceptible
to Heatstroke or Sunstroke
People more susceptible to heatstroke
or sunstroke are:
i. Infants
ii. Old people with renal, cardiac or
pulmonary disorders
iii. People doing physical labor under
sun
iv. Sportsmen involved in continuous
sports activities without break.
Features
Common features of heatstroke or
sunstroke are:
i. Nausea and vomiting
ii. Dizziness
iii. Headache
iv. Abdominal pain
v. Difficulty in
breathing
vi. Vertigo
vii. Confusion
viii. Muscle cramps
and convulsions
ix. Paralysis
x. Unconsciousness.
If immediate and vigorous treatment is
not given, damage of brain tissues occurs, resulting in coma and
death.
Heatstroke and
Humidity
Development of heatstroke depends upon
humidity of the environment. If the environmental air is completely dry,
exposure of body for several hours even to a temperature of 54.4°C (130°F) does
not cause heatstroke. If air is 100% humid, even the temperature of 41°C
(106.8°F) causes heatstroke.
Prevention
Heatstroke or sunstroke can be avoided
by the following measures:
i. Avoiding dehydration
by taking plenty of fluids such as water or sports drinks
ii. Taking frequent breaks during work
or sports activity
iii. Wearing light clothes with hat.
Treatment
Person affected by heatstroke or
sunstroke must be treated before the damage of organs. The subject
should be immediately moved from hot
environment and hospitalized
as
soon as possible. Immediate cooling of the body is the usual treatment. The
person must be immersed in cold water or cold water may be sprayed on
the skin. If water supply is not sufficient, cooling the
head and neck of the subject should be done first. Ice cubes can be rubbed on head
and neck. Ice packs must be kept under armpits and groin. Cooling efforts should
be continued till the body temperature falls to about 35°C
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