How to Work in Extreme Heat: Safety Precautions to Take

How to Work in Extreme Heat: Safety Precautions to Take
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Medically Reviewed By:
Mark Arredondo, M.D.

As climate change warms the planet, extreme heat is becoming more common in the workplace for millions.

Many jobs throughout the United States require working in extreme heat, and higher temperatures can cause conditions like heat exhaustion, cramps, fainting and heatstroke.

If you work in any of the following industries or positions, the Occupational Safety and Health Administration (OSHA) says you may be at risk for heat stress:

  • Agriculture

  • Construction

  • Landscaping

  • Delivery services

  • Oil and gas operations

  • Utility operations

  • Law enforcement

  • Fire services

Experts will explore what happens to your body in extreme heat, who should avoid working in these conditions and the best ways to protect yourself when temperatures rise.

What happens to the body under extreme heat conditions?

According to the Canadian Centre for Occupational Health and Safety (CCOHS), normal body temperature is set at 98.6° Fahrenheit. When it rises due to heat, this triggers certain body responses.

“The hypothalamus [gland], it reacts to temperature and in an extreme environment, [it] is going to … begin to increase the sweat glands in order to secrete sweat,” explained Dr. David Berry, a member of the American Red Cross Scientific Advisory Council.

The CCOHS notes that the movement of blood to the surface also allows more heat to escape your body through the skin.

However, the U.S. Centers for Disease Control and Prevention says your body’s sweat may not evaporate quickly enough in extreme heat to cool you down, or you may become dehydrated. This can lead to:

  • Higher than normal body temperature

  • Headaches

  • Dizziness

  • Nausea

  • Vomiting

  • Fatigue and weakness

  • Pale or red skin

  • Skin that’s hot to the touch

  • Rapid pulse

  • Muscle pain or spasms

  • Heat rash

  • Heavy sweating initially, with no sweating as body heat rises

What can working in extreme heat do to you?

Here are some of the main health impacts that the CDC says to watch for when you’re working in extreme heat.

Heat cramps

Sweating a lot in the heat depletes water and salt in your body and can lead to heat cramps. You’ll notice pain or spasms in your muscles, particularly in your arms, legs and abdomen.

Heat rash

Sometimes the skin becomes irritated from sweating in the heat, and a heat rash can develop. It looks like red blisters or raised pimples on the skin.

Heat exhaustion

When you’re in the heat for several days and you’ve become depleted of fluids, heat exhaustion can set in. You may notice excessive sweating, pale skin, dizziness, weakness, fatigue, fainting, headaches, nausea, vomiting and muscle cramps.

Heat stroke

If your body temperature rises and you’re unable to release enough sweat into the air to cool down, heat stroke can occur.

The CDC notes that heat stroke starts above 104° F. Your temperature can go as high as 106° F within 10 to 15 minutes, which can lead to permanent disability or even death.

Who shouldn’t work under extreme heat conditions?

The following health conditions or lifestyle factors make it hazardous to work in extreme heat.


The CDC recommends avoiding extreme heat if you’re aged 65 or older. This is because as you age, it becomes more difficult to regulate body temperature. Older people may also be more prone to health conditions or take medications that raise the risk for heat-related illnesses.


“Certain medications can increase your risk of developing heat stroke,” Berry noted.

The CDC says that these include:

  • Psychotropics

  • Parkinson’s disease medications

  • Tranquilizers

  • Diuretics (aka “water pills”)

Excess weight

OSHA and the CDC both advise that extra weight can lower your ability to properly cool down. According to a review published recently in the Handbook of Clinical Neurology, this may be because fat tissue acts as a “barrier” to heat loss and affects your body’s heat-regulating abilities.

Kidney disease

People with kidney disease can experience kidney failure or electrolyte imbalance that leads to hospitalization when dehydration occurs, according to the Canadian Broadcasting Corporation (CBC).

Cardiovascular issues

The CDC says anyone with high blood pressure or heart disease is at increased risk for heat stress and related illnesses.

Breathing conditions

Heat and humidity may pose a risk to people with breathing conditions because some research shows they can irritate and inflame the lungs, according to the CBC.

How can you protect yourself?

Understanding how to work in extreme heat can help you reduce your risk of developing heat-related health issues.

Drink plenty of fluids

Berry recommends staying hydrated by drinking “10 to 20 ounces of water every 20 minutes or so.”

He also notes that replacing electrolytes like salt is important when you sweat.

“One of the reasons why we get things like cramps is as we sweat, we do lose electrolytes, sodium potassium in particular,” he advised. “And so [drinking] a carbohydrate-based beverage [can help].”

Dress to stay cool

The best way to dress in extreme heat is by wearing loose-fitting, light-colored clothing, says the CDC. Breathable fabric like cotton is best.

Stay aware of your condition

Monitoring you and your coworkers’ symptoms can ensure you get the help you need when heat illness occurs.

Take more frequent breaks

Moving into air conditioning a few hours a day or putting cool water on the skin can help prevent heat-related health problems, according to the American Red Cross. The National Institute for Occupational Safety & Health provides a work/rest schedule based on the outside temperature, humidity and degree of direct sunlight.

To discover more about working in extreme heat, check out OSHA’s Hazard Alert guidelines.


Dr. David Berry, PhD, member, American Red Cross Scientific Advisory Council and department chair, kinesiology, Saginaw Valley State University, Michigan

Occupational Health and Safety Administration: Overview: Working in Outdoor and Indoor Heat Environments

Canadian Centre for Occupational Health and Safety: Hot Environments — Health Effects and First Aid

Centers for Disease Control and Prevention: Frequently Asked Questions About Extreme Heat

Centers for Disease Control and Prevention: Heat Stress

Centers for Disease Control and Prevention: Heat and Older Adults

Handbook of Clinical Neurology: Obesity and Thermoregulation

Canadian Broadcasting Corporation: How extreme heat impacts the body — and why it eventually kills you

The American Red Cross: Extreme Heat Safety

National Institute for Occupational Health & Safety: Heat Stress Work/Rest Schedules

Occupational Health and Safety Administration: Hazard alert: Extreme Heat Can Be Deadly to Workers

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