Beat the Heat

In July 2023, at a construction site in Kansas City, Missouri, 29 men and three women started their workday in an unusual way: by swallowing a pill-sized data-collection device. The devices would monitor their body temperature as they labored in heat that averaged around 88 degrees, with 50 to 70% humidity.

The results were alarming. Over three days of data collection, 43% of workers’ body temperature reached 100.4 degrees—the level of a low-grade fever, the University of New Mexico–led study found. And 4% of workers exceeded 101.3 degrees.

Keeping workers safe is a growing challenge in a rapidly warming world. The 10 hottest years on record have all occurred since 2013, with 2023 breaking thermometers as the hottest year ever, according to data from the National Oceanic and Atmospheric Administration. El Paso, Texas, endured 44 days of temperatures at or over 100 degrees last summer, beating the previous record of 23 consecutive days in 1994. Phoenix suffered 31 straight days of 110 degrees or higher in 2023, shattering the old record by 13 days; some projections show the Arizona city facing 102 days a year of extreme heat by 2050.

For workers, searing temperatures can increase the risk of conditions such as heat rash, heat cramps, heat exhaustion, heat stroke and dehydration. Heat-related illnesses can lead to a higher risk of hospitalization for heart disease, according to the U.S. Department of Health and Human Services. Dehydration can cause kidney issues and blood-pressure problems; heat stroke can inflict brain injuries and even result in death.

Most companies have strict programs in place to prevent heat-related illnesses. They start work early and modify schedules depending on the heat, provide crews with water, rest and shade, and maintain logs to monitor water intake. They train staff about heat symptoms, urge them to reveal if they’re feeling ill and encourage them to watch for struggling coworkers. They have an emergency-preparedness plan and first-aid procedures in place.

On elevated jobs, companies provide water on multiple floors, so workers at high elevations don’t have to come down to ground level for a drink. They provide large water containers not just for drinking but so workers can immerse their hands and forearms to reduce their skin and core temperature. They religiously emphasize safety procedures in daily meetings.

And yet some aspects of heat-related illnesses are still surprising. Want to test your heat expertise? Take this true/false quiz.

1. Crews are often dehydrated before they arrive at a worksite.

TRUE: In the University of New Mexico study, this was the most eye-opening result. More than 60% of workers were already dehydrated when they arrived at the job. In a similar study from the University of Copenhagen, roughly 70% of workers in five different industries, including construction, were dehydrated when they began their workday.

Crews should begin hydrating the day before they’re exposed to the heat. Hydration “is a 24-hour long preparation process that involves consuming fluids the entire day prior to when you’ll be outside for an extended period of time,” according to University of Iowa Health Care.

“We preach this in safety meetings: As the heat starts to increase throughout the day, you can’t wait until you start feeling ill to hydrate yourself,” says Ledon Green, vice president with the Houston office of Performance Contractors, ABC’s 2023 Contractor of the Year. “If you wait until you start feeling ill, it’s too late.”

2. Heat stroke only causes physical symptoms.

FALSE: Heat stroke—which happens when body temperature reaches 104 degrees—can traumatize the human body. Symptoms can include nausea and vomiting, flushed skin, rapid breathing, seizures and an accelerated heart rate. But it can also affect behavior and mental state, resulting in confusion, agitation, slurred speech, delirium and irritability.

“One of the effects of heat is that people tend to be more forgetful, and they tend to have shorter tempers,” says Joe Xavier, ABC’s senior director of safety.

The mental and physical strain can affect safety. In a 2022 Oregon State University study of the state’s agricultural and construction sectors, traumatic injury rates rose significantly when the heat index was above 75 degrees, compared to more moderate weather. Traumatic injury rates increased by another 19 to 29% when the heat index rose to 90 to 119 degrees.

3. To stay hydrated, workers should drink at least eight ounces of water every 15 to 20 minutes.

TRUE: This is the standard from health agencies such as the Centers for Disease Control and Prevention and the Occupational Safety and Health Administration. “Most people feel like, ‘Well, I’m thirsty, so I’ll get something to drink,’” Xavier says. “But when there’s extreme heat, you have to keep drinking, so you never get to the point of being thirsty.”

Diet is important, too. The human body gets about 20% of its water from food. Watery foods include vegetables such as cucumbers and celery, plus fruits like strawberries and watermelon. During warm-weather months, Performance Contractors provides crews with fruit and frozen pops that have electrolytes and other essential ingredients.

4. Energy drinks can provide a safe boost to weary workers in the heat.

FALSE: Some energy drinks contain more caffeine than soft drinks or a cup of coffee or tea. That’s a problem when your body is working to manage the heat. “Drinking several energy drinks per day can raise your caffeine levels enough to affect your heart,” according to the CDC. “High caffeine levels can be risky when added to the strain placed on your body by heat.”
Alcohol is also problematic. Beer and booze can cause dehydration, so workers should avoid alcoholic beverages within 24 hours of laboring in the heat.

One alternative beverage worth considering: sports drinks. For jobs lasting longer than two hours, OSHA recommends providing employees with beverages containing electrolytes. Typically, however, regular meals and adequate water intake should help to maintain a good electrolyte balance.

5. Heat affects everyone differently.

TRUE: Not everyone responds the same way to high temperatures. Reactions can vary based on everything from workers’ ages to their fitness levels. Medications can also cause heat intolerance. Examples from the Mayo Clinic include blood-pressure meds, antihistamines and psychiatric meds such as antidepressants.

“People need to understand that, just because they feel fine, doesn’t mean that their coworker feels fine,” Xavier says. “We need to watch out for each person and have that culture where you can speak up. If you’re already taking a 10- or 15-minute break an hour and you’re staying hydrated and you still feel off, make sure you say something. Or use the buddy system and say something if your coworker looks ill.”

As Green puts it: “Nobody knows your body better than you do. If you start feeling ill, make sure you voice it.”