Factors That Contribute to Heat Stress

When you hear “heat stress,” the first thing that you think of is probably a hot, sunny day in the middle of summer. And while it’s true that working in the hot sun can certainly contribute to heat stress, it’s far from the only factor that we must consider.

This article will go over seven contributors to heat stress other than the heat. Heat stress can sneak up quickly on you, but knowing what causes or exacerbates it will help you stay safe.

Heat Stress Factors You Might Miss

There are three categories of factors that determine the degree to which an individual is at risk for heat stress:

• Personal risk factors 
• Job factors
• Environmental factors

Environmental factors are often the most commonly considered. After all, it’s harder to forget about the possibility of heat stroke when you’re spending the day working in the heat.

But personal risk factors and job factors are often overlooked – and the results can be deadly.

1. Medication

Some medications can affect the body's ability to tolerate (and effectively deal with) heat. Workers taking medication for the following conditions should be particularly vigilant:

• Colds, allergies, and congestion
• Blood pressure
• Diarrhea
• Psychosis
• Depression
• Dizziness or vertigo

 2. Alcohol Use

Workers who have had alcohol in the past 24 hours are more susceptible to heat-related illnesses, as alcohol negatively impacts the body’s ability to regulate its temperature. Alcohol use can also contribute to dehydration, which can further spur on the development of heat stress.

3. Acclimatization

New employees and those who are returning from time away from the heat should do so slowly to allow the body to get used to the temperature.

Workers already acclimatized may be more prone to heat stress when there is a sudden change in temperature at the worksite, such as heat waves or when there is mining in the area.

4. Proximity to Hot Equipment

Workers doing tasks with, or in close proximity to, engines and other heat-generating equipment are at increased risk for heat illnesses. The equipment produces heat that raises the temperature in the work area, and it doesn’t take long before workers’ own temperatures start rising.

5. Clothing and PPE

Some PPE is heavy and lacks the ability to breathe, making it easy for the body to overheat. Workers should pay special attention to the coated and non-woven materials often used in protective garments, which prevent the evaporation of sweat. In general, the heavier the clothing, the longer it takes for evaporation to effectively cool the skin (working with fire risks? Consider these 6 Key Fire Resistant Protective Clothing Options).

6. Fluid Loss

While this factor varies heavily from person to person, workers who lose more than 1.5 percent of their body weight in a single day from sweating are at greater risk of heat stress. This can be remedied by ensuring adequate fluid intake to balance the fluid loss.

7. Work Schedule

Doing strenuous work during the hottest parts of the day puts workers at severe risk for developing heat-related illness.

When possible, modify work schedules so that strenuous work is done early in the morning and later in the afternoon, instead of mid-day. This will help prevent exposure to extreme heat.