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Childhood Illnesses and Conditions
: 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

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 include:

  • Clammy, pale skin
  • Sweating
  • Dry mouth
  • Tiredness(fatigue)
  • 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

    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
  • Seizures
  • 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 waves:

  • 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 helpseven for young babies and infants.

  • 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 do it.

  • 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:<24C(<75F)  - Activities allowed

    WBGT:24-25.9C(75-78.6F)  - Longer rest periods, drink water every 15 minutes

    WBGT:26-29C(79-84F)  - Stop activities for high risk children, and limit activities of others

    WBGT:>29C(>85F)  - 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 and Conditions

    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.

    © Autograph Communications Inc., All rights reserved