We all learned in science class that homeostasis is the self-regulating process by which our bodies maintain stability. One of the most important functions of homeostasis is the regulation of body temperature, which is called thermoregulation. Thermoregulation is the homeostatic process that allows the human body to maintain its core internal temperature of 98.6 degrees Fahrenheit or 37 degrees Celsius.
All thermoregulation mechanisms, such as sweating and shivering, are designed to return the body to its internal core temperature. If a worker’s internal core temperature is compromised while working in hot and humid working conditions, the worker becomes vulnerable to heat stress or heat induced illnesses. According to OSHA, thousands of workers are negatively impacted by heat stress each year and some even die from it.
What is heat stress?
Heat stress occurs when the body is no longer able to cool itself by sweating because the surrounding air temperature is close to or exceeds core body temperature. When the body is unable to cool itself by sweating, several heatinduced illnesses can occur, such as:
- Heat cramps—Muscle spasms associated with cramping in the abdomen, arms and calves often caused by losing large amounts of salt/ electrolytes and water through physical exertion
- Heat rashes—The skin’s sweat glands are blocked and the sweat produced can’t reach the surface of the skin to evaporate. This causes inflammation that results in a rash with tiny red blisters or bumps on the skin. Sometimes the bumps can be white or yellow as well.
- Heat exhaustion—The body overheats when the body’s cooling mechanism to maintain a normal core temperature begins to fail, usually from excessive heat and dehydration. Untreated, heat exhaustion can lead to heat stroke. (See chart below.)
- The often fatal heat stroke— Heat stroke is considered a medical emergency where the core body temperature is greater than 104 degrees Fahrenheit causing complications with the central nervous system.
Heat stress risk factors
Any job site—indoors or outdoors—that can raise a worker’s internal core temperature increases the risk of heat stress. High heat environments, high humidity areas, radiant heat sources, direct physical contact with hot objects, or strenuous physical activities can induce heat stress in employees. Other risk factors include weight, physical fitness and acclimatization, dehydration, metabolism, use of alcohol or medications, blood pressure, and age.
OSHA lists temperatures over 91 degrees as a moderate risk and advises to implement precautions that reduce heat stress. When the heat index ranges from 103 degrees and above, safety managers should be prepared to issue a heat stress alert and implement aggressive protective measures. Prone to heat stress Certain industries, occupations, and sports activities expose people to heat stress. These include but are not limited to military operations, moving companies, welding and metal forging, commercial laundries and bakeries, firefighters, boiler room workers, construction workers, and factory and automotive workers.
Outdoor operations in direct sunlight and hot weather, such as farming, construction, oil and gas well operations, and landscaping also increase the risk of heat-related illness in exposed workers.
Sporting and recreational events, such as 5K runs, marathons, fishing, even lying on the beach, can also induce heat stress, especially if the event takes place in a hot and humid climate.
Don’t forget that excessive heat may increase the risk of other injuries at the jobsite resulting from a worker’s sweaty palms, fogged-up safety glasses, and dizziness. Burns may also result when a worker accidentally comes in contact with hot surfaces or steam.
10 preventative measures
Take note of these preventative measures that every safety manager should practice to reduce the risk of heat stress.
1. Practice acclimatization, which is short work exposure early in the hot season, followed by gradual increases in intensity and duration.
2. Allow for frequent work breaks in an area that is cooler than the work environment.
3. Tell workers to drink plenty of water before, during, and after their shift and provide that water.
4. Tell workers to wear light-colored, loosefitting clothing.
5. Tell workers to avoid sugar, alcohol and caffeine, especially during heat waves.
6. Provide a hydration station with easy access to cool air or shade, water, fans, etc.
7. Implement a heat advisory program when a heat wave is forecasted or the heat index reaches 103 degrees. This can be as simple as putting an alert notice on a worker’s locker, at the time clock, or at the water cooler. Another tactic is to send a text to your workers with the heat advisory alert.
8. Train employees about heat stress, its risks and symptoms. OSHA has a Heat Stress Quick Card PDF that is available at https://www.osha.gov/Publications/osha3154.pdf.
9. Formulate a buddy system where workers help monitor each other for the symptoms of heat stress.
10. Invest in PPE cooling products, such as cooling towels and neck wraps, head bands, and head shades, ice-packet vests, wetted overgarments, heat-reflective aprons or suits, and moisture-wicking apparel.
Cooling towels and neck wraps
Cooling products today are high tech and help accelerate the evaporative cooling process. The advanced technology allows for workers to stay cool for an extended length of time. Plus, when the coolness wears off, the cooling towel, neck wrap, headband or head shade can be quickly reactivated by submersion in water for two to three minutes and then twirling in the air to reactive the cooling technology.
In addition to keeping the worker cool during the work day, cooling towels and neck wraps also offer a convenient method to wipe away sweat from the face and eyes.
When specifying cooling products, ask these questions:
- Is the product made from materials that are anti-microbial?
- If the product is a headband or head shade, does it have a stretch-fit design which aids in comfort and a custom fit?
- If the product is a neck wrap, does it have a stretch loop feature that keeps the wrap secure around the neck?
- How long does the intense cooling experience last before it needs to be reactivated again?
Cooling products come in a variety of colors and patterns so they keep you cool, and they look cool too. Make sure your heat stress combat kit includes cooling products. They are economical, easy to use, and effective at reducing the risk of heat stress.