Safety & HCM Post

How to Beat Heat Stress

The arrival of warm weather brings the risks associated with heat stress, which can strike workers silently and quickly, with the potential to be deadly.

The danger is considerably less for those who are accustomed to hot conditions. It is most acute for those coming onto the site from a cooler climate or who work in areas where temperatures during the year run to hot and cold extremes. For example, the summer of 2001 saw a fatality at a service rig in northern Alberta in which the cause of death was heat stroke.

When the body is unable to cool itself through sweating, serious heat-induced illnesses can occur. The two most serious are heat exhaustion and heat stroke. If left untreated, heat exhaustion can progress to heat stroke and possible death.

Symptoms of heat exhaustion:

  • headaches, dizziness or lightheadedness
  • weakness
  • mood changes, such as irritability or confusion
  • upset stomach, vomiting
  • decreased or dark-colored urine
  • fainting or passing out
  • pale or clammy skin

What to do: Get medical aid. Move the victim to a cool, shaded area; loosen or remove excess clothing; provide cool water to drink (about a cup every 15 minutes); fan and spray with cool water.

Symptoms of heat stroke — a medical emergency:

  • dry, pale skin with no sweating
  • hot, red skin that looks sunburned
  • mood changes such as irritability or confusion
  • seizures or fits
  • unconsciousness, with no response

What to do: Call an ambulance. Remove excess clothing; fan and spray the victim with cool water; offer sips of cool water if the person is conscious; place ice packs in the groin area and armpits.

The longer you work in the heat the better your body becomes at adjusting to it. This is called acclimatization, and it’s something you can lose if you’re ill or away from work for a week.

Generally, there are two ways to acclimatize:
1. If you are experienced on the job, limit your time in hot conditions to 50 percent of the shift on the first day, 60 percent on the second day and 80 percent on the third day. You should be able to work a full shift the fourth day.

If you are not experienced on the job (a summer student, for example) you should start off spending 20 percent of the time in hot working conditions on the first day and increase your time by 20 percent each subsequent day.

2. An alternative to reducing heat exposure times is to reduce the physical demands of the job for a week or two.

Until employees are acclimatized, they should take frequent breaks to cool down. Besides the need to acclimatize, personal factors that can contribute to an individual’s risks for heat stress are age, fitness level and medical conditions.

All employees should be encouraged to drink plenty of fluids, such as water and Gatorade, to replace electrolytes, but they should avoid carbonated beverages. These increase dehydration and give a false sense of being properly hydrated.

Use of alcohol the evening before a shift can also lead to dehydration.

Clothing that is light in both weight and color is best for working outdoors in hot weather. In a high radiant heat situation (e.g. hot vessels and equipment), reflective clothing may help. For very hot environments (e.g. cleaning the inside of tanks and vessels), clothing insulated by air, water or ice could be considered. This, coupled with setting time restraints to control heat exposures (30 minutes working, 30 minutes resting) aid in avoiding heat-related illnesses.

Vapor barrier clothing, such as chemical protective suits, greatly increases the amount of heat stress on the body, and extra caution is necessary.


  • The difference between heat exhaustion and heat stroke?
  • How to acclimatize to hot conditions?
  • The best clothing to wear outdoors in hot weather?




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