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Heat Illness Prevention

What is Heat Stress?

Heat stress occurs when the body cannot get rid of excess heat. When this happens, the body temperature rises, heart rate increases and a person may experience a range of symptoms from sweating (or lack of sweating) to dizziness and collapsing.

Heat stress can result in a number of heat related illnesses, including heatstroke, heat exhaustion, heat cramps and heat rash.

Heat can also increase the risk of injuries due to sweaty palms, fogged up safety glasses, etc.

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What Causes Heat Stress?

Workers at risk of heat stress typically include outdoor workers and workers in warm or hot environments.


What Else Causes Heat Stress?

  • High outdoor temperature
  • Layers of clothing/PPE
  • Dehydration
  • Decreased urination
  • High humidity
  • Direct sunlight
  • Intensity of work
  • Non-A/C workspaces
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Heat-Related Illness Symptoms & Causes

When left untreated, heat stress can lead to heat-related illness, which can progress rapidly. It is important to know the symptoms and causes of heat-related illnesses so you can be on the lookout for yourself and others.

Heat Rash

Heat rash is a skin irritation caused by excessive sweating during hot, humid weather.

First aid measures for heat rash includes drying the area/keeping the area dry and applying powder.

Heat Cramps

Heat cramps are debilitating, painful muscle cramps that can happen when working in a hot environment. Sometimes the affected muscles are the ones being used the most (calves and hamstrings, hands, or lower back).

First aid measures for heat cramps include having a small snack and drinking water or liquid that replaces carbohydrates and electrolytes. Move to a cool area and take a break. Get medical help if cramps do not subside in 1 hour or if the worker has heart problems.

Heat Exhaustion

Heat exhaustion is the body’s response to an excessive loss of water, salt, or both. Left untreated, heat exhaustion can lead to heatstroke.

Symptoms of heat exhaustion include excessive thirst, headache, weakness, and loss of consciousness. Additionally, nausea, vomiting, muscle cramps and dizziness.

First aid measures for heat exhaustion include removing the worker from the heat and have them sit in a cool area. Remove unnecessary clothing including shoes and socks. Have them sip water and/or electrolytes. Cool the worker with cold compresses or have them splash their face and arms with cool water.


Heatstroke is the breakdown of the body’s temperature control system. It occurs when the body can no longer control its temperature, resulting in a rapid rise in body temperature that can cause organ damage, brain damage, and even death.

Heatstroke can be life threatening. In non-lethal cases, heatstroke can result in permanent disability, so it is imperative that those suffering heatstroke symptoms receive emergency treatment.

Symptoms of heatstroke include fainting, high body temperature, powerful headache, lack of sweating, vomiting, and confusion.

First aid measures include all listed previously for other symptoms, and try to rapidly cool the person with ice baths and fans. 911 should also be called.

Prevention is the best way to manage heat-related illness.

Some tips to prevent heat stress include:


Drink plenty of water.

You need to drink more during hot weather, regardless of how active you are, even if you do not feel thirsty (check with your doctor if you are on limited fluids or fluid pills). Avoid alcohol or drinks that contain lots of sugar. Do not drink extremely cold liquids, as they may cause stomach cramps.

Avoid exposure to heat.

Stay out of the sun as much as you can, plan work earlier or later in the shift.

Protect yourself outside.

If you must be outdoors, remember to protect yourself from the sun by covering exposed skin with lightweight clothes, using sunscreen, and wearing a hard hat neck cover / sun brim, ‘seek’ shade and ‘slide’ on shaded safety glasses.

Take breaks.

Rest often and, whenever possible, stay in the shade.

Stay cool.

Keep air circulating around you. Keep yourself cool by using wet/damp towels.

Check in on others

Keep in touch with colleagues, do not allow them to work alone and check on them often especially on any extreme heat day.

Plan ahead.

Too much activity on a hot day can lead to heat stress. If you can, restrict activity to cooler parts of the day.

Keep your energy levels up.

Eat smaller meals more often and cold meals such as salads.