Tackling the Complexities of Heat Stress

It is imperative to understand how to protect individual workers’ health under hot conditions. Knowing all aspects of heat risks on the job saves lives, boosts productivity, and allows business continuity.

The first step is recognizing the two main effects of heat stress on the body: heat exhaustion and heat stroke.


When workers experience goosebumps or chills, lightheadedness, nausea, and/or feel weak or more fatigued than usual, they are likely experiencing heat exhaustion. These warning signs alert the individual that their cardiovascular system is no longer functioning at the level needed to complete the current workload. The heart rate increases under hot working conditions and “tops out” when the heart has trouble pumping enough blood to the muscles, depleting them of energy and inhibiting the skin from shedding body heat. At this point, work will become difficult if not impossible, and a worker may suffer heat exhaustion.


Exertional heat stroke (EHS) is more advanced, and thus more serious, than heat exhaustion. EHS is a medical emergency. If not properly treated, EHS can result in death. The good news is EHS is 100 percent preventable.

A worker can experience EHS very suddenly, without any warning signs. Symptoms include vomiting, hot and sweaty skin, and fatigue. EHS happens when:

• Core body temperature is greater than 104°F (40°C).

• The central nervous system experiences dysfunction. A person may hallucinate, become aggressive, irritable, confused, and/or irrational and become weak to the point of fainting or collapsing.


Workers should use a buddy system while on the job. This means checking on a specific co-worker’s wellbeing regularly. If one person notices something strange or out of character with the other, the observer should alert the supervisor for an intervention.

Workers should also pay attention to their own symptoms and what their bodies are telling them, and be diligent about stopping work to take a break and cool the body.

Ignoring or pushing through warning signs in an effort to speed up or continue the pace of work should be discouraged. Heat stresses decrease productivity on the job because the work pace slows and errors are more likely to occur. A worker who collapses on the job stops all work and reduces the number of people on the team as she/he heads to the hospital.

New methods of detecting heat stress, such as smart personal protection equipment (PPE) worn by workers, that monitors and measures core body temperature and physiological changes sends signals to both workers and their supervisors when a safe heat threshold has been crossed and a break or treatment are necessary.


When heat stress in the body occurs, workers should stop work, seek shade or air conditioning, drink hydrating fluids (especially water), and sit down to rest. Elevating the feet also speeds recovery.

After a 10-15-minute break, if the symptoms have subsided, a person is safe to return to work. If symptoms persist, professional medical attention is necessary. EHS should immediately trigger a 911 call. While waiting for additional help to arrive, the worker should continue to be treated to cool down as quickly as possible. This can be done with an ice bath or by rotating cold compresses around the body.


During the cold and flu season, measuring core body temperature to determine heat stress becomes more complex because a fever from a virus, including coronavirus, can also cause core body temperature to rise. Best practices for prevention, detection, and treatment to keep body temperature at optimal levels should always be the norm, regardless of the time of year.

Heat-detecting smart PPE can also be helpful in detecting the onset of illness because smart PPE monitors an individual’s physiological changes continually throughout the workday, during which a person can contract a virus. Since COVID, taking a worker’s temperature with a thermometer as she/he reports to work has become the most common method of detecting illness. The drawback to this current standard is that it only provides a single point reading at the beginning of a shift. In addition, this level of public screening can be quite embarrassing for a worker who is now sent home from work in a very public way even before the work day begins.

Whether it be temperature at the start of the day or information collected from the body continuously, data should be safeguarded by the organization, particularly when it is personal health information. It is important for individuals to know how their personal information is being collected and used, and for employers to receive only the data needed to take an informed action to keep the worker safe. Privacy policies are quickly evolving in the smart PPE industry to ensure data is both useful and protected.


Tools and equipment used for heat prevention, detection and treatment that incorporate technology and are used in hazardous locations must be certified as intrinsically safe (IS). Such products are labeled as intrinsically safe and are designed to have specific electrical and thermal characteristics that will not cause an explosion in the workplace.

Cell phones and smart PPE are of special concern as each contain batteries, capacitors and inductors that are capable of storing large amounts of energy. Each of these elements has the potential to produce a spark and/or start a fire if their energy is released quickly and unexpectedly, resulting in the “spontaneous combustion” of gas and air particles.

To be certified intrinsically safe, devices go through a series of specialized tests performed by Underwriters Laboratories, the Mine Safety and Health Administration (MSHA), and test labs such as the Intertek Group. The IS-certification process begins at the start of each product’s design and is performed in tandem with product development. Product developers and manufacturers build safeguards into each piece of their product and the system as a whole in preparation to meet stringent IS standards.

Understanding all the important aspects of working in hot conditions is imperative to keeping people safe, and companies protected. The details regarding identification, treatment and prevention of heat stress injury described in this article should allow you to start the next working day with new ways to manage a hot, dangerous situation for the best possible outcome.

Skip Orvis is vice president of engineering at Kenzen. Skip has more than 20 years of product development experience for both the consumer and industrial markets. He is also a U.S. Navy veteran who has experience working in extreme conditions through multiple deployments to the Middle East.

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