Heat illness: signs, first aid and when to call 911

What are the types of heat illness?

NIOSH lists six: heat stroke, heat exhaustion, rhabdomyolysis, heat syncope, heat cramps and heat rash. They run from mild to deadly. Heat stroke is the most serious. It is always a 911 emergency. The others need prompt action, and some need medical care too.

This table is a field summary of NIOSH’s guidance. It is not medical advice. When you are not sure, treat it as serious and call for help.

What are heat rash and heat cramps?

Heat rash is a skin problem. Heat cramps are muscle pain. Neither is usually an emergency, but both are warnings that a worker is losing a lot of sweat. Treat them and watch the crew for more signs.

Heat rash. NIOSH describes heat rash as a skin irritation caused by excessive sweating during hot, humid weather. It looks like red clusters of pimples or small blisters, usually on the neck, upper chest, groin, under the breasts and in elbow creases. NIOSH says the worker should work in a cooler, less humid place if possible, keep the rash dry and apply powder for comfort. Do not use ointments and creams.

Heat cramps. NIOSH says heat cramps usually affect workers who sweat a lot during strenuous activity. The sweating depletes the body’s salt and moisture, and low salt in muscles causes painful cramps. They may also be a symptom of heat exhaustion. NIOSH’s steps:

1. Drink water and have a snack or a drink that replaces carbohydrates and electrolytes, such as sports drinks, every 15 to 20 minutes.
2. Avoid salt tablets.
3. Get medical help if the worker has heart problems, is on a low sodium diet, or has cramps that do not go away within 1 hour.

Read about heat cramps and heat rash in the glossary.

What is heat exhaustion?

Heat exhaustion is the body’s response to losing too much water and salt, usually through heavy sweating. NIOSH lists the signs as headache, nausea, dizziness, weakness, irritability, thirst, heavy sweating, elevated body temperature and decreased urine output. It is a warning that can turn into heat stroke.

NIOSH’s first aid for heat exhaustion:

1. Take the worker to a clinic or emergency room for medical evaluation and treatment. Call 911 if medical care is unavailable.
2. Have someone stay with the worker until help arrives.
3. Remove the worker from the hot area and give liquids to drink.
4. Remove unnecessary clothing, including shoes and socks.
5. Cool the worker with cold compresses or have them wash their head, face and neck with cold water.
6. Encourage frequent sips of cool water.

Do not send a worker with heat exhaustion back to work to “walk it off.” See the full comparison in our heat exhaustion vs heat stroke guide. Our post on early signs crews miss lists the quiet ones.

Why is heat stroke an emergency?

Because it can kill or disable a worker fast. NIOSH says that when heat stroke occurs, body temperature can rise to 106°F or higher within 10 to 15 minutes, and it can cause permanent disability or death if the worker does not get emergency treatment. Call 911 first.

NIOSH describes heat stroke as the point when the body can no longer control its temperature: temperature rises rapidly, the sweating mechanism fails, and the body cannot cool down.

Signs of heat stroke:

• Confusion, altered mental status, slurred speech
• Loss of consciousness
• Hot, dry skin or heavy sweating
• Seizures
• Very high body temperature

What to do. Call 911 first.

1. Call 911 for emergency medical care.
2. Stay with the worker until emergency medical services arrive.
3. Move the worker to a shaded, cool area and remove outer clothing.
4. Cool the worker quickly. NIOSH lists a cold water or ice bath if possible, wetting the skin, cold wet cloths, or soaking clothing with cool water.
5. Circulate the air around the worker.
6. Place cold wet cloths or ice on the head, neck, armpits and groin.

Heat stroke does not wait for a supervisor to be sure. If you are not sure, call 911. Read about core body temperature in the glossary.

What is rhabdomyolysis?

Rhabdomyolysis, or rhabdo, is a medical condition NIOSH ties to heat stress and prolonged physical exertion. It causes rapid breakdown, rupture and death of muscle. NIOSH says it can cause irregular heart rhythms, seizures and kidney damage. It needs medical care.

NIOSH lists these signs of rhabdomyolysis:

• Muscle cramps or pain
• Abnormally dark (tea or cola-colored) urine
• Weakness
• Exercise intolerance
• No symptoms at all in some cases

A worker with signs should stop activity, drink more liquids (water preferred) and seek immediate care at the nearest medical facility. NIOSH adds that the worker should ask to be checked for rhabdomyolysis, which means a blood test for creatine kinase.

What about fainting and heat syncope?

Heat syncope is a short fainting spell or dizziness. NIOSH says it usually happens when a worker stands for too long or stands up suddenly after sitting or lying down. Dehydration and lack of acclimatization can contribute. Have the worker sit or lie down in a cool place and slowly drink water, clear juice or a sports drink.

If a worker faints and does not wake up quickly, treat it as an emergency and call 911. Ask the safety professional on your team how to handle follow-up.

Who is most at risk?

Anyone can get a heat illness, but some conditions raise the risk. NIOSH names high temperature and humidity, direct sun exposure, indoor radiant heat, limited air movement, lack of acclimatization, dehydration, physical exertion, and protective equipment and clothing. It also names physical condition and health problems, certain medications, advanced age, pregnancy and a previous heat-related illness.

Use that list to watch the right people. A new hire doing heavy work in full gear on a humid day with no shade checks several boxes at once. Give that worker lighter work, more rest and a buddy.

Prevention lives in the plan. See the heat stress prevention pillar, the acclimatization schedule and the jobsite hydration plan.

What does a supervisor do in the first minutes?

A supervisor stops the work, looks at the worker, and picks one of two paths: call 911 or move to first aid. Minutes matter, so train on this before the heat arrives.

1. Stop and look. Is the worker confused, slurring, seizing or unresponsive? If yes, this is heat stroke. Call 911.
2. Stay. Never leave the worker alone. Use the buddy system. NIOSH recommends workers watch each other for signs.
3. Move. Get the worker out of the sun to shade or a cool area.
4. Cool. Follow the steps for heat stroke or heat exhaustion above.
5. Report. Tell the safety manager and write down the time, place and what you did.
6. Review. After the event, review the plan. See the heat stress prevention pillar.

NIOSH says workers and supervisors should be trained about heat-related illnesses, symptoms and first aid. Put that training on the calendar before the first hot week. The heat toolbox talk kit is a five-minute way to start.

What should a five-minute heat illness talk cover?

Cover one page of facts, then ask the crew to say them back. Use the toolbox talk format and keep it short.

1. Name the six illnesses. Heat rash, cramps, fainting, exhaustion, rhabdo and heat stroke.
2. Teach the heat stroke signs. Confusion, slurred speech, seizures and loss of consciousness.
3. Say the rule out loud. Heat stroke means 911. Do not wait.
4. Practice the cool-down. Where is the shade, the water and the cold cloths?
5. Assign buddies. Each person watches one other person.
6. Say who reports. Any sign in yourself or a coworker goes to the supervisor right away.

Our heat toolbox talk kit has a script. For a quiet-signs list, read the post on early signs of heat illness crews miss.

Where is the printable one-page card?

JMAR publishes an emergency protocol page for crews. Print it, post it at the water station and review it in toolbox talks. Check it against the NIOSH steps above, and have your safety professional approve any change.

JMAR’s own app says: “Rapid Restoration Drops are a safeguard, not a substitute for emergency care. In any suspected heat stroke or medical emergency, call 911 immediately.”

Where do electrolytes fit?

They support hydration. They do not treat heat illness. Rapid Restoration Drops are a dietary supplement that replaces electrolytes lost in sweat. They are not medicine, and they are not a substitute for medical care. Water, rest, shade, acclimatization, training and 911 come first.

For label facts, see the liquid electrolyte drops pillar. To see how JMAR helps crews build a plan with onsite toolbox talks and coaching, see the hydration programs. For the rule side, read OSHA heat rules. This page is general information and not medical advice.

Where can I learn more?

• Heat exhaustion vs heat stroke: a field guide to telling them apart.
• Heat stress prevention: the plan that keeps crews out of trouble.
• Heat toolbox talk kit: a five-minute script.
• Emergency protocol: JMAR’s printable card.
• Compare hydration formats: how drops, powder, sports drinks and more differ.

Next step

Book a free 15-minute demo with JMAR at calendly.com/jen-jmarsolutions/15-min-meeting. You can also ask for a free sample or request bulk and government pricing.