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Working in the heat

Signs to watch for, what to do, and your rights. Every line comes from OSHA, CDC NIOSH or the National Weather Service, with the source under it. Not medical advice: your clinician decides. En español

Heat stroke: call 911. Cool the person right away.

Signs: confusion, slurred speech, passing out, seizures, heavy sweating or hot, dry skin, very high body temperature, fast heartbeat.

Do now: call 911. Move them to shade or air conditioning. Take off outer clothing. Cool them with cold water or an ice bath if you can, or ice or cold wet towels on the head, neck, trunk, armpits and groin. Fan them. Stay with them.

Not sure? Cool the worker and call 911.

Call 911 OSHA: “When in doubt, cool the worker and call 911.” osha.gov/heat-exposure/illness-first-aid · CDC NIOSH: “Call 911 for emergency medical care.” cdc.gov/niosh

Heat exhaustion

Signs: headache, nausea, dizziness, weakness, irritability, thirst, heavy sweating, higher body temperature, peeing less.

Get medical care: a clinic or emergency room. Call 911 if no care is near.
Get them out of the heat. Give liquids to drink, in frequent sips of cool water.
Take off extra clothing, including shoes and socks.
Cool them with cold compresses, or have them wash head, face and neck with cold water.
Someone stays with them until help arrives.

CDC NIOSH, Heat-Related Illnesses: “Take worker to a clinic or emergency room for medical evaluation and treatment.” cdc.gov/niosh/heat-stress/about/illnesses.html

OSHA: you do not need to know which illness it is. Symptoms can overlap and get worse fast, so give first aid as soon as any sign shows.

OSHA: “Do not try to diagnose which illness is occurring.” osha.gov

Water, rest, shade

Water: about 1 cup (8 oz) every 15–20 minutes for moderate work in the heat lasting under 2 hours. Don’t wait until you feel thirsty: drink on a regular schedule.
Not too much: generally, no more than 6 cups an hour.
Rest: when heat stress is high, employers should require breaks. Skipping breaks in hot conditions is not safe.
Shade: rest in a cool place: shade, an air-conditioned vehicle, a building or tent, or a spot with fans and misters.

CDC NIOSH: “For moderate activities in the heat that last less than 2 hours, drink 1 cup (8 oz.) of water every 15–20 minutes.” “Generally, fluid intake should not exceed 6 cups per hour.” cdc.gov/niosh/heat-stress/recommendations · OSHA: “Workers should not rely on feeling thirsty to prompt them to drink.” “In hot conditions, skipping breaks is not safe!” osha.gov/heat-exposure/water-rest-shade

New to the heat? Build up slowly.

Take 7 to 14 days to work up to a full day in the heat. In the first few days, take every symptom seriously. A worker with symptoms should be allowed to stop working.

Day	New workers	Workers with previous experience
1	No more than 20% of the usual time in the heat	No more than 50%
2	Add no more than 20% a day	No more than 60%
3	(so 60% at most)	No more than 80%
4	(so 80% at most)	100%

Breaks in air conditioning do not undo it.

CDC NIOSH: “No more than 20% of the usual duration of work in the heat on day 1”, “No more than 20% increase on each additional day”, “Taking breaks in air conditioning will not affect acclimatization.” cdc.gov/niosh · OSHA: “Workers who develop symptoms should be allowed to stop working.” osha.gov

Today’s heat check

Type the temperature and humidity from your weather app or a thermometer, or the heat index if you already have it. It works on this phone only: no location asked, nothing sent.

Heat index	NWS band
80–90°F	Caution: fatigue possible with long exposure or physical activity
90–103°F	Extreme Caution: heat stroke, heat cramps or heat exhaustion possible
103–124°F	Danger: heat cramps or heat exhaustion likely, heat stroke possible
125°F or more	Extreme Danger: heat stroke highly likely

Bands and wording: National Weather Service, weather.gov/ama/heatindex. Formula: NWS Weather Prediction Center, wpc.ncep.noaa.gov heat index equation. Heat index is for shade and light wind; NWS: “exposure to full sunshine can increase heat index values by up to 15°F.” weather.gov/safety/heat-index

Long, sweaty shifts

For jobs longer than two hours, employers should provide drinks with electrolytes, such as sports drinks: water cannot replace the salt you sweat out. To estimate your own sodium for a long shift, use the sweat calculator on this site (an estimate, on your phone).

High blood pressure, heart or kidney problems, pregnant, or on blood-pressure medicine? Don’t add salt on our say-so: take the question sheet to your clinician. Your clinician decides.

OSHA: “For longer jobs that last more than two hours, employers should provide electrolyte-containing beverages such as sports drinks.” osha.gov · CDC NIOSH: “If sweating lasts for several hours, drink sports drinks containing balanced electrolytes.” cdc.gov/niosh

Planning for a whole crew (coolers, shift length, day-by-day ramp)? See the crew shift planner.

Your right to speak up

Federal law gives you the right to work in a safe place.
You can speak up or report safety concerns without being punished or treated unfairly.
You can file a confidential complaint with OSHA and ask for an inspection.
If you are punished for using your rights, you can file a whistleblower complaint within 30 days.
OSHA: 1-800-321-6742 (1-800-321-OSHA).

OSHA Worker Rights and Protections: “You can speak up or report safety concerns without being punished or treated unfairly.” osha.gov/workers

In a mental-health crisis: call or text 988.

Sources: osha.gov/heat-exposure · cdc.gov/niosh/heat-stress · weather.gov/ama/heatindex · osha.gov/workers. Printed from sweatsciences.com/work-heat. Educational, not medical advice.

Sources

Each page below was read on 2026-10-26. Quotes are copied from it.

OSHA, Heat-Related Illnesses and First Aid: heat stroke and heat exhaustion signs; “When in doubt, cool the worker and call 911.”; ice bath “is the best method to cool workers rapidly in an emergency”; “Workers who develop symptoms should be allowed to stop working.” https://www.osha.gov/heat-exposure/illness-first-aid
CDC NIOSH, Heat-Related Illnesses: heat stroke first aid (“Call 911 for emergency medical care.”) and heat exhaustion symptoms and first aid. https://www.cdc.gov/niosh/heat-stress/about/illnesses.html
CDC NIOSH, Heat Stress Recommendations: “drink 1 cup (8 oz.) of water every 15–20 minutes”; “Generally, fluid intake should not exceed 6 cups per hour.”; “If sweating lasts for several hours, drink sports drinks containing balanced electrolytes.”; acclimatization over 7 to 14 days, 20% then 20% a day for new workers, 50/60/80/100% for workers with previous experience. https://www.cdc.gov/niosh/heat-stress/recommendations/index.html
OSHA, Water. Rest. Shade.: electrolytes for jobs over two hours; breaks when heat stress is high; “skipping breaks is not safe”; shade, air-conditioned vehicle, building, tent, fans and misters. https://www.osha.gov/heat-exposure/water-rest-shade
OSHA, Worker Rights and Protections: right to a safe workplace, speaking up without punishment, confidential complaint, 30-day whistleblower window, 1-800-321-6742. https://www.osha.gov/workers
National Weather Service, Heat Index: Caution 80–90°F, Extreme Caution 90–103°F, Danger 103–124°F, Extreme Danger 125°F or higher, with the effect on the body for each. https://www.weather.gov/ama/heatindex
NWS Weather Prediction Center, The Heat Index Equation (Rothfusz regression and adjustments, used on this phone by the heat check). https://www.wpc.ncep.noaa.gov/html/heatindex_equation.shtml
National Weather Service, Heat Index safety page: full sun can raise heat index values by up to 15°F. https://www.weather.gov/safety/heat-index
988 Suicide & Crisis Lifeline, Get Help: call or text 988. https://988lifeline.org/get-help/