The following describes heat-related illnesses and how to recognize and treat them. The illnesses are presented in order of increasing severity. If workers show signs or report symptoms of heat-related illnesses, they should be removed from the hot environment and, if necessary, treated by an occupational first aid attendant or a physician.
Heat rash
- Rash or worsening of existing skin problems
- Intense itching
- Prickly sensations
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- Leave the hot environment, preferably until the rash has healed.
- Keep the affected areas clean, cool, and dry as much as possible.
Heat cramps
- Muscular pain or spasms
- Excessive sweating
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- Move the worker to a cooler environment. If possible, lay the worker down and remove or loosen tight-fitting clothing.
- Cool the worker by sponging with cool water and fanning. Take care not to cool the worker too much. If the worker begins to shiver, stop cooling.
- If the worker is fully alert and not nauseated, provide oral fluids. Juice, non-caffeinated soft drinks, commercially available oral rehydrating solutions (sport drinks), or a solution of salt water (1 teaspoon of salt in 0.5 litres of water) are best. Alcoholic and caffeinated beverages are not recommended.
Heat exhaustion
- Shallow respiration
- Increased respiratory rate
- Weak, rapid pulse
- Cool, pale, clammy skin
- Sweating
- Weakness, fatigue, dizziness
- Headache and nausea
- Fainting
- Muscle cramps
Signs and symptoms are the same as for mild shock. The presence of sweating is an important finding, because it is often the only way to differentiate heat exhaustion from the life-threatening heat stroke.
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- Move the worker to a cooler environment. If possible, lay the worker down and remove or loosen tight-fitting clothing.
- Cool the worker by sponging with cool water and fanning. Take care not to cool the worker too much. If the worker begins to shiver, stop cooling.
- If the worker is fully alert and not nauseated, provide oral fluids. Juice, non-caffeinated soft drinks, commercially available oral rehydrating solutions (sport drinks), or a solution of salt water (1 teaspoon of salt in 0.5 litres of water) are best. Alcoholic and caffeinated beverages are not recommended.
- In most cases, the patient’s symptoms will improve dramatically within 30 minutes. These patients should still be transported to medical aid.
Heat stroke
- Hot, dry, flushed skin
- Absence of sweating
- Agitation, confusion
- Decreased level of conciousness
- Headache
- Nausea and vomiting
- Seizures
- Increased respiratory rate
- Irregular pulse rate
- Shock
- Cardiac arrest
The presence of hot, dry, flushed skin without any evidence of sweating is one of the important findings that differentiate heat stroke from other heat-related illnesses. Heat stroke can occur quickly and without warning.
Heat stroke is a medical emergency
Notify the first aid attendant, call 911, and/or arrange for immediate transportation to medical aid.
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- Maintain airway, breathing, and circulation as required.
- Move the worker to the coolest place available.
- Lay the worker down on their back unless the worker is actively vomiting or having a seizure. In this situation, place them in the three-quarter prone or on-the-side position.
- Remove all outer clothing and apply cold water to the worker by either dousing or applying wet cool sheets. Spraying or sponging the entire body with cold water is also effective. Fanning will also help.
- If the worker is fully alert and not nauseated, provide oral fluids. Juice, non-caffeinated soft drinks, commercially available oral rehydrating solutions (sport drinks), or a solution of salt water (1 teaspoon of salt in 0.5 litres of water) are best. Alcoholic and caffeinated beverages are not recommended.
- Transport the worker to medical aid and continue to cool during transport.
To learn more about heat stress, read Preventing Heat Stress at Work.
