Introduction to heat stress

Exposure to high temperatures and humidity can place you and your team at risk for heat stress. Any work or environment that raises body core temperature to 38 degrees or higher can potentially result in heat stress and related illnesses, including heat stroke, heat exhaustion, heat syncope (fainting) and muscle cramps, to name a few.

Heat can cause additional hazards, such as loss of grip due to sweaty palms; loss of vision due to fogging of safety glasses; distractions or loss of focus from sweating; and even burns when in contact with hot surfaces.

What you need to know

Heat stroke is a life-threatening condition. A person experiencing heat stroke may appear red-faced, hot to the touch, dry (no sweat), confused or unresponsive.

Anyone exposed to high heat and humidity can experience heat stress and related illnesses. But workers who are ages 65 and older, are overweight, have heart conditions or high blood pressure, or take certain medications are at greater risk. Certain tasks requiring coveralls or chemical body suits, welding, or working around kilns and furnaces can also increase risk.

A person suffering from heat stroke requires immediate cooling with ice or air conditioning. You can also try spraying them with water to assist evaporative cooling, fanning them or relocating them to a shaded area. If the person is unconscious, call 911 and tell the dispatcher you have a heat stroke patient. Continue cooling the person, even if they show signs of regaining consciousness, until emergency medical services arrive to transport them to a medical facility.

Once the individual is en route for medical treatment, begin an investigation into the cause and any contributing factors. Determine if other employees are at risk and take preventive steps, such as offering breaks, water, or a change in physical duties, or moving them to a cooler environment.

Proactive measures employers can take to prevent heat stress include:

  • Encouraging employees to drink at least 2 liters of water over an eight-hour shift
  • Offering frequent, short breaks in an air-conditioned break room
  • Providing fans or a shaded area to rest that is away from the hot environment, if break rooms are not available.

Monitor ambient temperatures to remain aware of the risks. When forecasts include heat advisories, adjust schedules so more strenuous work can be performed earlier in the day, if possible. Moving air with fans may be helpful but if the ambient temperatures are already over 38 degrees, simply moving hot air will not provide much relief.

Other heat stress conditions include heat exhaustion (the onset of heat stroke), fainting and heat cramps. Though they are not life-threatening like heat stroke, these conditions can cause interruption to the workflow and increase risk for illness and serious injury.

For any heat-related condition that is not heat stroke, get the person to a cooler area and provide tepid or cool (not iced) water., For heat cramps, lighten physical exertion levels for the remainder of the shift, if possible.

Bodies acclimatize to hot environments within seven to 14 days. New hires or those assigned to new tasks need to have physically strenuous activity introduced gradually to prevent heat stress. The risk of heat stress is reduced once a person adjusts to the heat.

How to prepare

  • Be aware of when heat stress is likely to occur.
  • Take preventive measures to reduce overall heat exposures and provide short, frequent breaks whenever workers are exposed to heat.
  • Schedule strenuous work assignments for cooler times of the day, rotate employees assigned to strenuous work and create air flow with fans.
  • Provide water at work stations or electrolyte-replacement drinks (not soda or salt tablets).
  • At the start of the summer or whenever new employees are assigned to work in areas of high heat and humidity, expect the risk of heat stress to be greater initially and allow for acclimation.
  • Train your team on proper hydration and the signs and symptoms of heat stress.
  • Observe team members throughout the shift and create a buddy system for employees to watch out for one another.

Key takeaways

  • Work environments with high heat and humidity expose employees to heat stress.
  • Heat stroke is a life-threatening medical emergency. Knowing how to recognize heat stroke and what to do can help save an employee’s life.