Heat-Related Illness and Outdoor Workers

Each year, extreme heat and humid conditions affect thousands of workers, causing a range of heat illnesses that can affect anyone at any age

Reviewed by: Edward Bernacki, MD, MPH
Written by: Rocky Epstein and Ashley Lawrence

A top-down view of a person pushing a lawn mower through grass.

Sweltering heat and humidity, cooling off at Barton Springs, or sitting under a porch fan listening to cicadas in the late afternoon, these are the trademarks of a typical Austin summer day. As idyllic as summer seems for most of us, each year, extreme heat and humid conditions affect thousands of outdoor workers causing a range of heat illness that can affect anyone at any age in any condition. And, with temperatures reaching over 100 degrees, we may be looking at a record-breaking summer heat wave this year.

UT Health Austin’s Walk-In Clinic works closely with employers and employees to help educate, advise, and care for individuals who may be most at risk for heat-related conditions. As seen in the chart below, many risk factors contribute to heat-related illness, such as rhabdomyolysis, heat exhaustion, fainting, and heat rash:

Common Heat-Related Conditions:

  • Rhabdomyolysis is a serious condition brought about by trauma or contact, which causes the breakdown of a person’s skeletal muscle that is then released into the bloodstream. Brought on by heat exhaustion or heat stroke and without prompt attention, this condition can lead to kidney failure or even death. Outdoor workers and athletes may experience rhabdomyolysis after working or working out in the heat for prolonged periods. Affected individuals may complain about muscle pain, cramping, swelling, weakness, and decreased range of motion in their joints. Another sign of rhabdomyolysis is dark or tea-colored urine.
  • Heat exhaustion may precede heat stroke, a much more significant condition. With heat exhaustion, your body’s core temperature may rise to between 100 and 102 degrees. Common symptoms include a headache, nausea, vertigo, weakness, thirst, heavy sweating, irritability, and a decreased urine output.
  • Fainting or heat syncope can occur in workers who stand all day or rise suddenly from a seated position, causing a temporary drop in blood pressure. They may feel light-headed, dizzy, and sometimes faint. Dehydration and lack of acclimation are the main causes of this condition.
  • Heat rash may appear if a worker’s clothing is too restrictive. Tight clothing traps sweat close to the skin blocking the sweat glands. Sweat is unable to evaporate causing a red rash to appear. The rash will appear bumpy and red as well as give off a prickly or hot sensation. It is important to remove tight or restrictive clothing to let the skin cool and air out.

Acclimate Early

Executive Director for UT Health Austin’s Walk-In Clinic Edward Bernacki, MD, MPH, says acclimating to the heat in the early days of summer is key to preventing heat-related illness. In an interview with KXAN, Dr. Bernacki explains how people usually need two weeks to acclimate to working in the heat. It is important to remember to build up your heat tolerance slowly, wear light, sun protective clothing, and make sure to hydrate regularly. He compares working in the heat to being on a sports team, explaining that football teams do not run out on the field in full pads on the first day, they start with shorts, shirts, a helmet, and participate in lighter, less intense practices with frequent water breaks. As the two weeks pass, coaches incrementally add more gear and a little more intensity to the workouts until athletes are able to fully gear up for practice. He advocates for the same incremental build-up for those who work outside during the summer.

Mind the Humidity

Humidity is as important as high temperatures when planning outdoor activities or work. Yes, humidity can mean the difference in how quickly a person may recover from heat exposure. When relative humidity is 75%, you cannot count on sweating alone to cool your body. However, high humid conditions and heat close to 100 degrees make it difficult to cool a person down. It is very important to cool a person’s whole body as soon as possible on high humidity days if they are suffering from heat illness. A pool of water is usually the fastest way to cool a body, but if you do not have access to a pool or lake, use water-cooled or cooling garments or wet towels to help bring down the body temperature. In less humid conditions, it may be easier to cool someone down using cool compresses, water, or by getting them to rest in a cool, shady location.

Wearing a Face Mask in the Heat

Wearing a face mask while working in the high heat and thick humidity may reduce your ability to breathe comfortably. Sweat can also make your mask become wet more quickly, promoting the growth of microorganisms.

Ways to minimize discomfort and keep yourself and others safe:

    • Check your face mask’s fit: Make sure your face mask fits properly and is tight enough to still allow you to breather normally.
    • Choose a breathable face mask: Cotton fabric is a more breathable option when it comes to using cloth face masks.
    • Carry extra face masks: Change out your face mask as soon as it becomes damp with sweat.
    • Take frequent breaks: Make time to step aside and remove your face mask. This is also a great time to hydrate.
    • Social distance: Take precautions by continuing to stay six feet away from others when changing out your face mask, hydrating, and even when wearing your face mask.

    What Can You Do?

    Dr. Bernacki emphasizes, “The time people really get into trouble is when we get that first strong heat wave. Be hyper-vigilant, although you always want to be vigilant, as that’s when heat illness usually occurs because people just aren’t used to the heat and humidity.”

    Ways to stay safe throughout the summer:

    • Take time to acclimate to the heat: It usually takes at least two weeks – don’t rush it.
    • Dress lightly for the weather: Wear breathable materials that are lightweight, such as cotton.
    • Take frequent water breaks: Drink 8 ounces of water every 20 minutes - no less, no more, because you can over-hydrate. Thirst should always be the best indicator of your need for water.
    • Limit work or play during the hottest part of the day: Plan outside activities in the early morning or late afternoon.
    • Check the heat index and follow heat safety tips: If you do work in the heat, the Occupational Safety and Health Administration (OSHA) and the National Institute for Occupational Safety and Health (NIOSH) have developed a helpful Heat App to help quickly assess the heat index. It also offers heat safety tips to keep you safe during the day. You can download it here for Apple and Android: OSHA/NIOSH Heat App.

    At UT Health Austin’s Walk-In Clinic, expert providers are available to help you weather the summer safely.

    About UT Health Austin

    UT Health Austin is the clinical practice of the Dell Medical School at The University of Texas at Austin. We collaborate with our colleagues at the Dell Medical School and The University of Texas at Austin to utilize the latest research, diagnostic, and treatment techniques, allowing us to provide patients with an unparalleled quality of care. Our experienced healthcare professionals deliver personalized, whole-person care of uncompromising quality and treat each patient as an individual with unique circumstances, priorities, and beliefs. Working directly with you, your care team creates an individualized care plan to help you reach the goals that matter most to you — in the care room and beyond. For more information, call us at 1-833-UT-CARES or request an appointment here.