Heat stress disorders
Numerous factors, like work load, clothing, and environmental conditions (i.e. temperature, humidity, air current & radiant heat), contribute to the heat balance in our bodies. If any of the factors are overlooked when managing work in hot conditions, heat stress disorders can develop.
Heat stress disorders occur when our bodies cannot maintain an average body temperature of 37°C as we try to get rid of heat. High heat and humidity force our sweat glands to work harder. If these glands cannot handle the heat stress, body temperature will rise. If unchecked, this can cause vital organs to malfunction and ultimately fail. Sickness and even death can result. Three common heat disorders are:
- heat cramps
- heat exhaustion
- heat stroke
Heat cramps
Painful cramps in the chest, abdomen, arms and legs can result if heavy sweating drains a person of salt. Cramps may occur immediately or be delayed by a few hours. Cramps are a warning that more serious heat disorders may occur if the stress continues. When heat cramps occur, move the worker(s) to a cool area, loosen their clothing and have them drink cool water or a sports drink.
Seek medical attention immediately if the cramps last for more than an hour, the worker is on a low sodium diet or the worker has heart problems.
Heat exhaustion
Heat exhaustion occurs when the body’s cooling system cannot keep up with the heat stress. Sweat contains a balance of important fluids and salts. If lost water and salt are not replaced, the body becomes dehydrated. Signs of heat exhaustion include:
- heavy sweating
- cool, pale, and moist skin
- body temperature greater than 38°C
- fast, weak pulse
- normal or low blood pressure
Victims may be tired, weak, clumsy, upset or confused. They are usually very thirsty, panting and may have blurred vision. They can also be nauseated and vomit or faint. Affected workers should be moved to a cool area, have their clothing loosened, given sips of water and put a cool, wet cloth on the body or take a cool bath.
Since heat exhaustion can lead to heat stroke, provide first aid and send workers to a doctor.
Learn more about heat exhaustion.
Heat stroke
Heat stroke develops when all the water and salt available for sweating has been used up.
The body’s temperature rises to above 40°C, the skin becomes hot, dry and red. Affected workers may act strange, be weak, confused, have a fast and strong pulse, headache, feel nauseated or be dizzy. In later stages, victims may faint or have convulsions.
Heat stroke can kill. Anyone in this condition must be taken to a hospital immediately.
Preventing heat stress disorders
- Engineering controls such as fans, air conditioning and spot cooling should be used if workers must frequently work indoors under hot conditions.
- Cooling measures such as rest breaks, providing adequate supplies of drinking water and ensuring workers are well trained to recognize heat disorders should be implemented for occasional hot indoor and outdoor work situations.
- Factors such as work load, air temperature, humidity, air flow and radiant heat must be taken into account to give a more accurate measurement of risk. This includes Humidex values.
For more information on working under hot conditions, see the WorkSafe publications, Working Under Hot Conditions and Hot Conditions Guidelines, below:
