This document outlines the recognition, treatment, and prevention of heat-related illnesses by providing guidance for medical supervision, hygienic practices and training programs.


Exposure to hot environments and extreme heat, indoors or outdoors, can result in illnesses, including heat rashes, heat cramps, heat exhaustion, heat syncope and heat stroke. Contact with hot surfaces, steam, or fire may result in other heat injuries, such as burns.

Heat can also increase workers’ risk of injuries, as it may result in sweaty palms, fogged-up safety glasses, dizziness, and may reduce brain function responsible for reasoning ability, creating additional hazards.

Occupational exposure to heat can also result in reduced productivity.


  • Drink plenty of water.
  • Take your break in the shade or in air-conditioned area.
  • Report any heat symptoms early.
  • Check your urine colour.


Heat stress is the net heat load, consisting of the sum of environmental and metabolic heat to which a person is subjected.

Heat strain is the body’s physiologic response to heat stress. People may be at risk for heat stress and concomitant heat strain, when exposed to hot environments or even when engaged in strenuous physical activities.

Extreme heat/heat waves refer to soaring temperatures, affecting a particular region for a prolonged period (two or more consecutive days).


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Heat Stress Guiding Principles

Heat Stress