IntroductionEmergency Ambulance

The human body functions effectively only when the body temperature is maintained within fairly narrow limits.  An increase or decrease in body temperature out of these limits can lead to incapacity and in extreme cases, death.

The information provided within this article is not intended to act as a replacement to professional advice but merely to provide the reader with an overview of common issues associated with physical activity, exercise and hot climates.

Heat Illness

Heat illness can be defined as: when the performance of an individual is impaired as a result of a rise in body temperature.

Types of Hot Climate

Hot climates are those in which cooling by evaporation of sweat is required during at least some part of the day to keep the body temperature within normal limits.  Hot climates may be divided into:

  • Hot wet climates that are typical of the tropical jungle with high humidity and little daily temperature variation; and
  • Hot dry climates are those of desert and semi desert areas.  The sky is clear and air temperature may go up to 122 degrees Fahrenheit or even higher during the day with a marked fall in temperature at night.

Acclimatisation to Heat

Acclimatisation to heat is a process of adaptation by the body, which reduces the effects of heat stress. The main changes occurring are:

  • Increased blood volume;
  • Decreased pulse and body temperature in response to constant stress; and
  • Increased sweat production with a reduction of its salt content.

Conditions Affecting Heat Illness

Physical activity leads to increased heat production by the body.  This heat load is lost to the air around the body partly by convection to cooled air, but mainly by evaporation of water through the lungs and skin.   Sweating leads to the loss of body water and salt.  When sweat production is restricted or it is not able to evaporate due to clothing, then the core temperature will rise and heat illness may occur.  Other factors that can and will affect the individual are:

  • Environmental conditions; and
  • Individual conditions.

Environmental Conditions

Heat illness may result from one or more of the environmental conditions that include:

  • Local weather.
  • Work intensity.
  • Water intake.
  • Clothing and equipment.
  • Acclimatisation.

Individual Conditions

Heat illness may also result from one or more of the following individual conditions or a combination of both types of conditions:

  • Obesity.
  • Lack of physical fitness or lack of sleep.
  • Illness.
  • Congenital disorders.
  • Recent alcohol intake.
  • Dehydration.
  • Medication or illegal drugs.
  • Nutritional status.

Types of Illness

Heat illness can be divided into the following categories:

  • Heat exhaustion; and
  • Heat stroke.

In practice it is hard to define the division between the two.  For the purpose of this article “heat illness” is all embracing and applies to an individual who becomes incapacitated as a result of a rise core body temperature.

The Key to Prevention

The key to prevention of heat illness is an awareness of the risk by fitness professionals and those involved in the training of clients.


Warning signs may begin with muscle spasms (cramps) or fatigue at normal temperature.  If left unattended this could lead to the following symptoms:

  • Agitation.
  • Nausea or vomiting.
  • Disturbed vision.
  • Staggering/loss of co-ordination.
  • Confusion, collapse or loss of consciousness.
  • Hyperventilation over and above that which might be normally brought on by the activity being carried out.


Treatment consists of:

  • Stop the activity. This means stopping the activity for all others exposed to the same conditions. A single case may be a warning that a large number of individuals are at risk.
  • Lie the casualty down at rest in a cool place (elevate feet if conscious).
  • Remove outer garments.
  • Sponge or spray the casualty’s body with water.
  • Fan the casualty’s skin to improve evaporation.
  • Give frequent small drinks of water if the casualty is conscious.
  • If unconscious place in the recovery position.
  • Evacuate to medical care as quickly as possible.
  • The nearer the body temperature gets to 40 degrees centigrade, the more serious the condition may become.

Heat Induced Fainting

This is also known as Syncope. Individuals who are standing quietly after long periods of physical inactivity are more prone to faint in hot climate because of the increased strain on the circulation of blood.


The treatment consists of:

  • Lie the casualty down, raise and support the legs.
  • Reassure the casualty and give sips of water if conscious.
  • If unconscious check airway, breathing, circulation and place into the recovery position.


Sunburn is the reddening and blistering of the skin due to the ultra-violet content of the sun’s rays.  Protection is by means of gradual exposure or by the use of clothing or sun creams.  Sunburn may cause reduced performance or even hospitalisation.


Treatment of sunburn consists of:

  • Place the casualty in the shade.
  • Give the casualty sips of water.
  • For extensive blistering seek medical aid immediately.
  • Do not break any blisters.

Prickly Heat

This is a common heat condition causing irritation and reddening of the skin.  It is due to the blockage of sweat gland ducts by a plug of cells.  Skin abrasion by clothing and the use of harsh soaps and detergents can make the condition worse.


Treatment consists of:

  • Cool the affected area of skin with regular showers.
  • Minimise exertion until referred for medical treatment.

Prevention of Heat Illness

Remember prior to any activity carry out a risk assessment of both environment and individual factors.  Identify the hazard & implement safety measures.  The main preventative measures are:

  • Acclimatisation should provide a programme of gradually increased physical activity for new arrivals.
  • The replacement of water lost through sweating.  The quantity required would vary according to heat stress and the type of work being carried out but intake cannot be restricted.  If the urine is scanty and dark coloured more water needs to be drunk.
  • Clothing should be loose fitting to allow good ventilation and washed and changed frequently.
  • Adequate rest and sleep.
  • Maximum use of shade.
  • Early recognition of heat disorders.
  • First aid cover.
  • Sufficient instructor ratios.
  • Standard of fitness.
  • Work intensity.


Complications through heat illness can range from the individuals concerned missing valuable training to the very worst case scenario “death”.

Regardless of treatment outcome it may be advisable to consult your medical professional or the emergency services for advice.


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