Levitt-Safety Blog

How to prevent heat stress at work

Jonathan McCallumMarket Segment Manager: Occupational Health, Industrial Hygiene & Environmental MonitoringMay 8, 2023

Hundreds of workers in Canada are affected by heat stress every year. According to the United Food and Commercial Workers Union (UFCW Canada), an estimated 220 workers in Canada and the U.S. die each year from occupational heat stress.

Heat-related illnesses are cause for concern, and with summer almost here, it’s time for a refresher on the best ways to beat the heat at work. This guide will discuss the risks of heat exposure and our top tips and solutions to protect workers.

What is heat stress?

Heat stress happens when your body loses its ability to self-regulate its temperature. It’s a condition caused by a buildup of body heat generated by several factors, including the environment, physical effort, existing health and acclimatization of the worker, and the clothing and equipment the worker is wearing.

Working in hot environments for a prolonged period can drive your internal body temperature several degrees above the average temperature of 37°C, which overwhelms the body’s natural cooling systems. This is when danger occurs.

Heat exposure can affect worker performance and productivity but, in more severe cases, can cause heat-related illnesses and even death.

The most severe heat illness is heat stroke (with symptoms including headache, confusion and loss of consciousness). Other heat-related conditions include cramps, rash, exhaustion, and syncope (fainting while standing).

Before working in a very hot environment, managers should ensure workers are acclimatized to the heat, trained to recognize the symptoms of heat stress in themselves and their co-workers and have a heat stress prevention plan in place.

Occupational heat stress: Know the risks

In 2022, Canadians experienced record-setting summer temperatures, and in 2023 Canadians could be in for another scorching season, according to the Farmer’s Almanac’s long-range forecast. The report says most regions in Canada will experience ‘unrelenting heat’ with some temperatures expected to reach over 32°C from June to September.

Working in the intense heat of the summer sun can put workers at risk of heat stress. As summer temperatures rise yearly, employers and workers must take the necessary steps to protect themselves and each other from heat exposure.

Heat stress can affect workers in many different environments, including:

  • In foundries, steel mills, smelters, glass factories, and furnaces, where extremely hot or molten material is the primary heat source.
  • In outdoor occupations, such as construction, road repair, open-pit mining and agriculture, where the sun is the primary heat source.
  • In laundries, restaurant kitchens, bakeries, and canneries, where high humidity adds to the heat burden.

So, whether you work outdoors as a tree planter, inside a mill, or work year-round in hot environments like bakeries, food processing plants and underground mines, you may be at risk of heat exposure.

Of course, you can’t change the weather or the temperature you work in, but you can change your approach to working in the heat. When the temperatures are high, and the job involves physical labour, workers and employers can take preventive measures to protect themselves and each other.

Top tips for heat stress prevention

There are preventive measures employers can take to ensure optimal worker health and reduce the risk of heat stress in the workplace.

Here are a few tips to get you started.

Tip #1. Heat Stress Measurement:

Occupational heat stress management is often considered complex and time-consuming, but it doesn’t have to be. Heat stress monitors are incredibly useful for monitoring humidity and temperature and should be part of your heat illness prevention plan.

Standard thermometers only measure air temperature. Heat stress monitors consider air temperature, humidity, radiant heat, and airflow—making them the preferred way to measure workplace environmental heat on-site.

Heat stress monitors can be placed in the work area or worn as a wearable device, allowing managers and workers to get real-time insights into their work environment.

Personal Heat Stress Monitoring

A personal heat stress monitoring device is a wearable armband that can provide personal values as part of a heat stress prevention plan. Sensors measure the person’s heart rate, core body temperature, exertion and more. The unit can alert the wearer and supervisor of changes that may affect worker safety on the job.

It can also alert management of critical safety alerts like an emergency or injury. With advanced software features, managers can view how their team is doing at any time, on any device, or anywhere in the world.

Area Heat Stress Monitoring

Work involving high air temperatures, radiant heat sources, high humidity, direct physical contact with hot objects, or even strenuous physical activities has a high potential for inducing heat stress in workers. They are generally used in factories, construction sites, and other places prone to high temperatures.

Environmental heat stress is measured by:

  • humidex, a combination of temperature and humidity, and
  • wet bulb globe temperature (WBGT), which considers radiant heat sources.

WBGT data is used for work/rest guidelines based on environmental conditions vs. core body temperature.

Levitt-Safety carries a variety of  WBGT monitors, which can provide you with a guideline for work and rest. 

LSI Heat Shield Heat Stress Monitor

The LSI Heat Shield system with a two or six-inch globe is an advanced worker heat stress instrument for industrial hygiene and health and safety professionals. It can be used as a handheld device, on a horizontal surface or mounted to any photographic tripod. 

Heat Shield integrates globe/wet bulb/dry bulb temperatures and relative humidity sensors to display and store the following:

  • WBGT indoor and outdoor index, and
  • humidex measurements.

Along with the LSI Heat Shield, we also carry some smaller handheld models:

Sper Scientific WBGT heat stress monitor with wet bulb

Tip #2. Hydrate:

Naturally, we lose water and salt when we sweat. This loss should be replenished by increasing fluid intake. Thersty is a hydration solution that can keep your team hydrated and performing at their best.


product image of a bottle of sqwincher fruit punch

Tip #3. Wear PPE that keeps you cool:

The Chill-Its 6700 Cooling Bandana features polymer crystal cooling technology for relief in extreme heat. Lightweight and low-profile, this comfortable cotton bandana is perfect for wear around the neck or under hard hats. A tie closure in the back makes for an adjustable, snug fit on a variety of head sizes.


product image of Pioneer orange safety shirt with hi-viz strips along shoulders and stomach

Head protection:

The new V-Gard C1™ Hard Hat from MSA helps alleviate heat stress for workers in sunny conditions with ReflectIR™ Thermal Barrier technology that keeps the hard hat interior up to 20°F (11°C) cooler.

Innovative features of the C1 that help to reduce heat stress:

  • Full brim provides additional shade and sun protection.
  • Optional large vents with strategic placement.
  • Premium moisture-wicking sweat band with breathable foam padding.

MSA C1 Hard Hat blue

PPE with cooling technology:

Choosing breathable clothing goes a long way to not overheating. The Chill-Its® line from Ergodyne is a great option for anyone working in the heat for many hours. Chill-Its uses polymer technology to keep you cool.

In its dry state, the polymer feels like little balls of sand. When soaked in cold water, these non-toxic, super-absorbent acrylic polymers expand and absorb water to create a cooling sensation for up to four hours. Just re-soak to active. 

You can also get heat stress PPE with cooling technology in the following styles:

ergodyne chill-its with evaporative technology

Heat Stress planning and prevention: A final word.

While you can’t control the weather, you can control how you and your team handle it. From knowing the risk factors and symptoms of heat-related illnesses, ensuring proper hydration and fighting back the heat with the right gear, you can make relatively minor adjustments that significantly impact your crew’s health, safety and productivity.

Ready to build your own heat stress prevention plan?

Contact us today to learn more about our heat stress prevention solutions and how we can help keep your team cool, safe and productive.