Heat Stress: The Hidden Hazard That Comes with Warming Weather

May 15, 2023 • Previsor

Heat stress is a hidden hazard that comes with warmer weather. The US Department of Labor reported 344 worker deaths related to heat exposure between 2011 and 2019. However, that number is likely much higher as it leads to other medical emergencies, including heart attacks. Heat stress doesn’t just happen. It’s a safety risk that can be avoided.

On this episode, we welcome back Rod Harvey, Director of Industrial Hygiene and Field Operations with RHP Risk Management. Harvey has more than 35 years of experience in environmental health and safety. He provides consulting services to clients in both the public and private sectors.

First, we’ll talk about the warning signs of heat stress. Then, we’ll discuss how employers can equip employees to handle high temperatures throughout the day. Finally, we’ll share short- and long-term solutions to working in hot conditions.

Listen to this episode of the WorkSAFE Podcast or read the show notes below.

Heat-related illness 101

Extreme temperatures have a negative effect on the human body. “As warm-blooded animals, humans are always striving to maintain a core body temperature of between 98 and 90 degrees Fahrenheit,” Harvey explained. “As we become exposed to heat, our body has certain mechanisms and physiological responses to start shedding that heat.” Heat-related illness occurs when our bodies can no longer cope. 

Learning the warning signs

Heat stress begins as the body attempts to cope with high temperatures. The body starts to sweat, losing fluid and electrolytes through the skin. Most people think of sweating as a normal response. After all, sweat cools the skin. Exercise, working in the yard, or even playing with kids can cause a person to sweat. Harvey highlights a few ways to know if the amount of sweat you’re losing is doing more harm than good:

  • Check your body weight. Are you losing too much fluid? Measuring yourself at the beginning and end of the day can reveal a state of dehydration.
  • Examine your urine. Dark-colored urine can indicate you aren’t retaining enough water to hydrate your body. The Occupational Safety and Health Administration provides a chart to help workers compare.
  • Feel your heartbeat. Is your heart pounding? Is your face red and flushed? Both are signs that the body is working extremely hard to keep up in a hot environment.

Other vital symptoms can appear when the body is under heat stress, such as dizziness, lightheadedness, a heat rash and muscle cramps. Prolonged exposure to heat overtaxes the body’s systems. When it can’t keep up, core body temperature begins to rise. This can lead to heat stroke, a severe overheating that can lead to death. These conditions are warning signs. When they appear, it’s time to take action.

Indoor heat risks

Heat stress doesn’t just occur outdoors. “Our exposure to heat comes from two primary sources,” Harvey shared. One is the environment. This includes temperature, humidity, wind, the warmth of the sun, and machine radiance. Hot equipment generates heat. A default solution many turn to is protective clothing. But protective equipment can prevent the body from sweating, the first line of defense against overheating. 

The second heat source is metabolic or exertional heat. “Our muscles are amazing pieces of equipment, but they’re very inefficient,” he added. “Most of the energy that they use to move us around is wasted as heat. So there’s an internal source of heat when you’re working hard, and that can become a significant source of heat.” 

Solutions to heat stress

Heat stress presents employers with a two-fold challenge. Just because an environment is cool doesn’t mean employees can’t overheat. How can they prevent high temperatures – or strenuous work – from draining their teams?

Hydrate before and during work

Whether indoors or outdoors, the key to avoiding heat stress is hydration. Harvey points out that not only do employees need to drink fluids during their shift but start by pre-hydrating as well. “It’s extremely beneficial to drink liquids, especially water, prior to the start of the exposure to heat a couple hours before,” he said. Then, regular hydration is needed about 20 minutes before and around every 15 minutes during work. 

“Don’t rely on your thirst to tell you when you need water,” he instructed. “If you’re working around heat or in heat, it’s best to drink water all day long.”

Build in rest schedules

As the heat starts to take a toll on the body, short breaks can help fend off symptoms. Harvey finds that people are better at taking breaks when not at work. For example, they stop to drink iced tea or get some air when working in the yard. But they aren’t always quick to do so when on the job.

“Short ten, fifteen-minute breaks away from the heat, preferably in an air-conditioned area, in an area that provides shade, is very beneficial,” Harvey said. “The body can recover pretty quickly if it isn’t strained too much, and then the work can continue. So really, it’s a combination of water, rest and shade.”

Train employees

One of the greatest defenses against heat stress is employees. We aren’t always aware when we are overheated. Under stress, we can lose our ability to think clearly. Employees under heat stress may:

  • Stagger when they walk
  • Experience slurred speech
  • Have trouble understanding directions

“The individual reaction to heat stress is so different between people,” Harvey explained. “On any given day, you can have people that are affected by the heat and the workload while other people aren’t.” The body can even be impacted differently by heat from day to day. 

Training employees to recognize the signs of heat stress allows them to watch out for their well-being and for the well-being of others. Harvey recommends a buddy system when working in hot environments. For employees who can’t work in pairs, a supervisor should call or check on them regularly throughout the day. If they start to feel unwell between these check-ins, then employees should be trained to notify their manager. This way, someone can keep tabs on them as they recover or offer assistance if needed.

Long-term solutions: Develop a heat management program

Heat-related illnesses are 100% preventable,” Harvey shared. A heat management program serves as a long-term solution to battling heat in the workplace. First, employers should conduct a hazard review. How big of a risk is heat on your job sites? At what temperature do things start to get uncomfortable in your region? Consider both indoor and outdoor environments. Are employees required to do a lot of physical activity? Put all of this information into a written plan. Include training elements, including:

  • Hydration. How should employees stay hydrated throughout the day?
  • Communication. What steps should they take if they notice the effects of heat stress on themselves or others?
  • Notification. If the impact of heat stress requires an emergency response, who is responsible for communicating that?

Written policies are always stronger when employees sign and acknowledge them. “That should all be spelled out in the written plan,” Harvey added, “And training should be done regularly. Certainly in the spring before the hot weather, if you’re in outdoor settings, and then regularly through that period so it’s top of mind for people, what they should be doing.” 

I think there needs to be a cultural shift and a recognition that employee safety has to come first if employees are being affected by heat stress,” he finished. “You can’t push them. You can’t tell them ‘Well, finish your shift and then we’ll get you some liquid or we’ll get you some some rest’. There has to be a recognition that this is a serious issue that can lead to unfortunately death.”

Employers can’t control the weather. Sometimes, weather can’t even be accurately predicted. But employers can plan appropriately and take preventative action where they can. Rest, water breaks, and long-term plans go a long way towards reducing the impact of heat in the job.

May 15, 2023
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