Heat Stress
Heat stress is a common risk in the workplace during the warmer summer months and if not recognized and treated immediately, can lead to serious illness. By assessing work activities and implementing controls, employers can protect their workers.



  • Radiant heat from direct or indirect sunlight
  • High Humidity
  • Air temperature that’s hotter than skin temperature


  • The more active or hard the work is, the more heat the worker will produce


  • Conditioning (regular work in hot environments makes workers less prone to heat stress)
  • Poor health such as obesity, advanced age, and medical concerns
  • Hydration
  • Clothing/PPE


Workers need to hydrate when their bodies heat up because they lose fluids and salt through sweat which make them less able to cool themselves down. The warning signs of heat stress when working in a hot environment are:

  • Excessive sweating
  • Dizziness
  • Nausea

If these stresses are not recognized and treated early, they can lead to serous disorders and effects on the body such as:

Heat cramps

  • Painful muscle cramps
  • Can lead to heat exhaustion

Heat exhaustion

  • Shallow breathing
  • Increased heart rate
  • Weak, rapid pulse
  • Cool, pale, clammy skin
  • Sweating
  • Weakness, fatigue, dizziness
  • Headache and nausea
  • Fainting
  • Muscle cramps
  • Can lead to heat stroke

Heat Stroke

  • No longer sweating
  • Agitation and confusion
  • Decreased level of consciousness and awareness
  • Headache
  • Nausea and vomiting
  • Seizures
  • Increased breathing rate
  • Irregular pulse
  • Shock
  • Cardiac arrest


Determine whether it’s necessary to work in hot conditions. Change work practices and policies accordingly to limit the risk. For example, consider whether work can be done during the cooler parts of the day. Monitor environmental conditions and make modifications to facilities, equipment, and processes to reduce heat exposure. Establish cooling areas and rest stations with shade and water. Ensure there is adequate first aid coverage and have emergency procedures in place. Most importantly, educate and train workers at risk for heat stress on how to recognize signs and symptoms and what to do in response. 

Heat stress and heat stroke are preventable conditions with awareness and defence. It’s important to recognize the symptoms of these conditions early and take action to prevent serous health concern.

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