Construction safety Heat stress Workplace exposures Seasonal safety: Summer

Causes of heat-related illnesses

Why do individual workers respond to heat so differently?


Responding is Michael Prewitt, operations and deployment manager, Kenzen, New York.

As workforces prep for the summer, employers may be looking at previous years’ data on worker heat stress and trying to identify patterns. There may be some patterns related to climate, but it’s more likely that the data per individual isn’t as simple and clear. That’s because lots of contributing factors determine how a worker responds to heat.

Here, we’ll discuss factors that can and can’t be controlled, and then provide insights into how an employer can be best prepared.

Genetics contribute to how much someone sweats and how they adapt to heat. Various diseases can affect heat response as well. Diabetes affects sweat gland function, which can make it harder for some individuals to cool down. Workers with skin disorders, such as psoriasis, or those who have received skin grafts can also have trouble sweating and cooling themselves in heat. Conditions affecting the cardiovascular system, such as high blood pressure, will also limit the body’s ability to thermoregulate in heat.

Additionally, once a person is over the age of 35, their ability to dissipate heat starts to decline.

Substances can affect susceptibility to heat illness as well. Prescription drugs such as antidepressants, sympathomimetics, anticholinergics and antipsychotics have been shown to impair sweat gland function and increase heat production. Over-the-counter allergy medications also impair sweat gland function.

Nicotine use alters sweating and skin blood flow mechanisms, making a worker more susceptible to heat illnesses. As a stimulant, nicotine also increases heart rate and blood pressure. This causes the cardiovascular system to work harder while it’s already stressed from the heat.

Alcohol use can lead to dehydration when working in the heat. If a worker doesn’t properly hydrate before and during work, they’ll be at increased risk for heat illness.

Diuretics have a similar impact as alcohol, causing the cardiovascular system to work even harder in the heat. Drugs that lower heart rate and blood pressure can make workers heat up faster.

These issues cannot be known by all members of an organization because of the federal law restricting release of medical information and other privacy practices, but a strong baseline can still be cultivated that gives each worker the best chance of managing work in the heat.

Staying physically fit makes it easier for a person to manage heat stress. Providing fitness incentives can help encourage your workers to prepare themselves for the hotter season.

Hydration is an obvious mitigation to heat stress. Ensure every worker has easy access to water and is aware of how much they should drink. Try not to chug water, as you can only absorb so much at time, and always drink when you’re thirsty.

The best way to ensure all workers are prepped for working in the heat is to acclimatize them correctly. Best practice is to allow two weeks for acclimatization. Spend an hour in the heat each day and increase the temperature they’re exposed to by almost 2° F each day. This will get your workforce as prepared as possible for the jobs in the heat of summer.

Editor's note: This article represents the independent views of the author and should not be construed as a National Safety Council endorsement.

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