5 Causes of Heat Stress and How to Avoid It

As the weather starts to get warmer in the northern hemisphere, the daily risks of heat stress and heat stroke increase. Workers in outdoor environments like those working in the utilities, oil & gas, and construction industries are at a greater risk.  Heat stress occurs when the body’s natural cooling processes fail to effectively regulate body temperature. Signs of heat stress can include fatigue, exhaustion, headaches, flu-like symptoms, cramping, dizziness, rash from excessive sweating, fainting and more. Not only is heat stress a health hazard, workers suffering from heat exhaustion are at greater risk for accidents since they are less alert and may not be able to think clearly. It is important to know the risks of heat stress and how to properly mitigate them to stay healthy and productive.

While the risk of heat exhaustion increase during the warmer summer months, there are many different factors that contribute to this hazard.


Contributors to Heat Stress:

  1. Work Environment. This includes the outdoor climate, but also the indoor work conditions, including lack of air conditioning in a building, or those who work alongside hot furnaces or machinery all day. A study on how office temperatures affect worker productivity conducted by Lawrence Berkeley National Lab in 2006 found that worker productivity declined in a hot environment. The study found a 9% decrease in productivity once “temperatures exceed the mid-80s”. According to the study, peak productivity was seen in an environment around 72 degrees.

  2. Age. It’s been found that those workers 40 and over are more prone to heat stress and exhaustion, and even more so for those 60 and over. Keeping this in mind will help ensure the proper precautions are being taken for those most at risk.

  3. Over-Exertion. The longer and more physically intense the workload, the easier it is to fall into heat stress. It is important to take frequent breaks in order to give your body rest.

  4. Hydration. Ensuring you stay properly hydrated, not just through the work day, but after work hours as well, has been proven to be effective in helping to prevent many health risks including heat stress. Research has shown that dehydration also leads to loss in productivity and an article posted by Safeopedia discussing this research notes that “just 2 to 3 percent water loss is enough to decrease energy levels by as much as 20 percent”.

  5. PPE. While PPE is not the main contributing factor to heat stress, it can play an important role in a holistic mitigation strategy. When asked about the top reasons for not wearing their PPE on the job, end users listed complaints such as uncomfortable and too hot. Previously flame-resistant clothing had a bad reputation for being hot and heavy. Over the past several years new innovations in fiber and fabric technology have been crafted for the purpose of changing the ‘rule’ that higher protection means heavier weight. Other developments including moisture wicking and fast dry fiber blends have proven to help combat heat stress through evaporative cooling. Providing workers PPE that reduces the risk of heat stress instead of contributing to it increases the probability that they will wear their PPE and wear it properly, reducing the risk of injury.

 With all of the above contributors, it is important to also acclimatize to these conditions. Per OSHA, “A good heat illness prevention plan takes into account the need for more breaks, a cool place to rest, the availability of fluids, and the careful allotment of time for a worker to become fully adjusted or acclimatized to the heat. It will need to be flexible based on the intensity of the heat, the level of humidity, the workers’ experience on the job, and the workers’ physical fitness.” See the infographic to the left from NIOSH on developing an acclimatization plan.

Overall, it’s important to keep heat stress at top of mind for on the job hazards. Keeping water/hydration stations accessible, allowing for rest breaks, and starting the job off by setting an acclimatization plan will help prevent the risks of heat stress and the implications this has on workers’ health and productivity.




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