: Heat Exposure Injury and Its Prevention
How does heat affect the body?
The effect of heat on the body is a result of three factors: humidity
level causing 70% of heat stress, sun radiation causing 20% and
the temperature causing 10% of heat stress. It is therefore important
to understand that the humidity level plays the most important
role in heat induced stress and illness. During heat waves, the
temperature is measured but the humidity is also recorded and
tends to bring up the temperature. This measurement is referred
to as the HUMIDEX.
How does heat affect the body?
Generally humans can control their internal temperature in the
heat by sweating. However under extreme heat and humidity conditions
the body cannot keep up and will suffer from heat stress. The
elderly and young children, as well as those with chronic respiratory
and heart conditions are more susceptible to heat induced injury.
What are the consequences of heat exposure?
Heat exhaustion usually occurs after prolonged exposure to heat
and/or heavy exercise in the heat resulting in increased loss
of body fluids through heavy sweating. The signs of heat exhaustion
Clammy, pale skin
Headache and or dizziness
How is heat exhaustion treated?
Children suffering from heat exhaustion need to be removed from
the heat immediately and given water to drink and cool compresses
on their skin. Fortunately, heat exhaustion is not life threatening,
and will resolve with rest, fluids and cooling down.
Heat stroke is a very dangerous and a potentially life threatening
form of heat stress or injury. The body is so overwhelmed by the
heat and humidity that it loses the capacity to sweat. This results
in very high body temperature which in severe cases can actually
cause brain damage and tragically, even lead to death. The signs
of heat stroke include:
Very high body temperature (103 degrees-F or higher)
Hot, red and dry skin
Absence of sweating
Deep or shallow breathing
A weak pulse rate
Confusion or hallucinations
Loss of consciousness
Heat stroke can occur suddenly and is an emergency
requiring immediate medical attention.
Prevention of heat injury
Clearly the best approach is to try to prevent heat injury
as it can potentially result in heat stroke which is very dangerous.
Here are some ways to prevent heat injury during heat/ humidity
Young children and babies should be dressed very lightly and not
bundled in blankets or heavy clothing.
Stay out of the heat and humidity by staying indoors during the
hottest time of the day(usually mid morning to mid afternoon).The
use of air conditioners if available helps…even for young babies
If the there are no air conditioners, try to stay at the lowest
level of the house as it tends to be cooler. Also, try to keep
the house as shaded as possible by closing window blinds and curtains.
A fan will help as well.
Do not stay or leave children in parked cars during hot weather.
Avoid vigorous exercise in the heat(this includes children as
well). If you have a young child or a child with chronic respiratory
conditions such as asthma, do not allow them to partake in sporting
events or exercise during heat waves especially when there is
a heat/humidity advisory in effect.
Drink plenty of fluids. Water is good. Sports drinks are good
too as they contain added salt. It is important to know that children
may not feel thirsty but will still need to drink regularly. Avoid
salt tablets. Avoid drinking caffeine containing beverages.
When in the sun keep track of how long a child has been outside.
Learn to recognize the signs of heat exhaustion right away so
you or your child can get shelter in order to avoid further heat
injury. Also, use your common sense and remove your child from
the sun/heat as frequently as you think is necessary. Do not over
If your children are swimming in a pool or beach, you still have
to be aware that the high humidity and sun rays are still a potential
threat. Proper sun-screen protection as well as frequent rests
in the shade are still necessary.
Children are unable to perspire as much as adults and therefore
are more prone to heat stress during exercise than adults. A sensible
approach must be used in determining if children can safely partake
in sports activities during heat/humidity waves.
What is the "WBGT"?
According to the American Academy of Pediatrics, the best way
of determining the heat and humidity risk is to measure the WBGT.
The WBGT, a measure of humidity, temperature and sun radiation
is determined by an apparatus called the psychrometer which is
available commercially. This apparatus is composed of three thermometers:
a wet bulb for humidity determination, a globe(black ball) measuring
radiation and a thermometer measuring the temperature. The American
Academy of Pediatrics recommends the following approach to restricting
activities in children during hot/humid spells based on the WBGT:
WBGT:<24ºC(<75ºF) - Activities allowed
WBGT:24-25.9ºC(75-78.6ºF) - Longer rest periods, drink water
every 15 minutes
WBGT:26-29ºC(79-84ºF) - Stop activities for high risk children,
and limit activities of others
WBGT:>29ºC(>85ºF) - Cancel all athletic activities
What about smog during heat waves?
The hot, humid air often carries pollutants, pollens and molds
in higher concentrations than usual. Under these conditions, breathing
this air may be harmful to younger children, and children with
chronic respiratory or cardiac conditions. During a smog and heat/humidity
alerts be extra careful by not letting your children outside as
long as the advisory is in effect.
Other Childhood Illnesses
The information provided in this site is
designed to be an educational aid only. It is not intended to
replace the advice and care of your child's physician, nor is
it intended to be used for medical diagnosis or treatment. If
you suspect that your child has a medical condition, always
consult a physician.
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