Heat-Related Illnesses at Work: Symptoms and First Aid

Workers exposed to extreme heat, outdoors or indoors, can develop heat-related illnesses. Workers and supervisors should be trained to recognise them and give first aid. They include:

Heat stroke — call 911

The most serious. The body can no longer control its temperature: it rises fast, sweating fails, and the body cannot cool down. Body temperature can reach 106 °F or more within 10 to 15 minutes, and without emergency treatment heat stroke can cause permanent disability or death.

Symptoms: confusion, altered mental state or slurred speech; loss of consciousness (coma); hot, dry skin or heavy sweating; seizures; very high body temperature. It is fatal if treatment is delayed.

First aid:

• Call 911, and stay with the worker until emergency services arrive.
• Move them to a shaded, cool place and remove outer clothing.
• Cool them quickly — with a cold-water or ice bath if possible, or by wetting the skin, placing cold wet cloths on it, or soaking clothing with cool water.
• Circulate air around them to speed cooling.
• Put cold wet cloths or ice on the head, neck, armpits and groin.

Heat exhaustion

The body's response to losing too much water and salt, usually through heavy sweating.

Symptoms: headache, nausea, dizziness, weakness, irritability, thirst, heavy sweating, raised body temperature, less urine.

First aid:

• Take the worker to a clinic or emergency room to be checked and treated; call 911 if medical care is not available, and have someone stay with them.
• Move them out of the heat and give them liquids; encourage frequent sips of cool water.
• Remove unnecessary clothing, including shoes and socks.
• Cool them with cold compresses, or have them wash head, face and neck with cold water.

Rhabdomyolysis

Linked to heat stress and long physical exertion, "rhabdo" is the rapid breakdown and death of muscle. Dying muscle releases electrolytes and large proteins into the blood, which can cause irregular heart rhythm, seizures and kidney damage.

Symptoms: muscle cramps or pain; abnormally dark, tea- or cola-coloured urine; weakness; exercise intolerance. It can also cause no symptoms.

First aid: stop the activity, drink more fluids (preferably water), get care at the nearest medical facility at once, and ask to be checked for rhabdomyolysis — a blood test for creatine kinase.

Heat syncope

Fainting or dizziness, usually after standing too long or standing up suddenly after sitting or lying down. Dehydration and not being used to the heat can contribute.

Symptoms: brief fainting, dizziness, light-headedness when standing long or rising suddenly.

First aid: sit or lie down somewhere cool, and slowly drink water, clear juice or a sports drink.

Heat cramps

Common in workers who sweat heavily during hard work, which depletes the body's salt and water; low salt in muscles causes painful cramps. Heat cramps can also be a symptom of heat exhaustion.

Symptoms: muscle cramps; pain or spasms in the abdomen, arms or legs.

First aid:

• Every 15 to 20 minutes, drink water and have a snack, or a drink that replaces carbohydrates and electrolytes, such as a sports drink.
• Avoid salt tablets.
• Get medical help if the worker has heart problems, is on a low-sodium diet, or has cramps that do not ease within 1 hour.

Heat rash

Skin irritation from heavy sweating in hot, humid weather.

Symptoms: red clusters of pimples or small blisters, usually on the neck, upper chest, groin, under the breasts and in elbow creases.

First aid: work somewhere cooler and less humid if possible, keep the rash dry, apply powder for comfort, and do not use ointments or creams.

Sources

• National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, "Heat-related Illnesses." https://www.cdc.gov/niosh/heat-stress/about/illnesses.html
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