Cold Stress – Learn to Prevent and Treat It

Cold Stress Learn to Prevent and Treat It

You’re probably familiar with weather-related illnesses like heat stroke and heat exhaustion, but did you know that illnesses just as serious can also be caused by working in cold environments?

The winter, like the summer, poses unique workplace hazards that should be mitigated through workplace controls and personal protective equipment (PPE). These winter illnesses, referred to broadly by the term “cold stress,” include conditions you’ve probably heard of like frostbite and hypothermia. Some less well-known cold stress illnesses include trench foot and chilblains, and these problems are also serious medical issues.

Temperature, wind speed and humidity/wetness combined put workers at risk in the winter. Employers and workers both need to understand the risks of working in the cold, as well as how to prevent and treat cold stress illnesses. The first step is learning what types of illnesses could occur and how to recognize the symptoms in yourself and others.

Types of Cold Stress Illnesses


Hypothermia occurs when your body temperature gets too low and you can no longer produce heat. When wintery conditions are particularly cold and windy, your body has to work hard to maintain its normal temperature of 98.6 degrees. Over time, you lose more and more heat, which puts you in danger.

Common symptoms of hypothermia are shivering, loss of coordination, fatigue and confusion, according to the National Institute for Occupational Safety and Health (NIOSH). If a person suffering from hypothermia doesn’t get inside quickly, more serious symptoms can develop such as a stop in shivering, dilated pupils, slowed pulse and blue skin. In serious cases, the person may lose consciousness (although hopefully your workers will be able to recognize the signs of hypothermia and address the situation before it comes to this).

General first aid for hypothermia, according to NIOSH, involves moving the victim into a warm place, removing wet clothing, and heating the body beginning with the center (chest, neck, head) using blankets. Warm beverages—nonalcoholic and decaffeinated—can help warm the body, too. Depending on the severity of the person’s symptoms, medical attention may be necessary.

Immersion Hypothermia

A sub-category of hypothermia exists called immersion hypothermia. This illness occurs when a person is submerged in water. According to NIOSH, “It develops much more quickly than standard hypothermia because water conducts heat away from the body 25 times faster than air.” In situations where this type of hypothermia is possible, workers must be prepared to quickly rescue anyone who becomes submerged in water.


You’re probably familiar with frostbite, which happens when parts of the body actually freeze. In cold weather, your body works to maintain its core temperature, which means extremities and exposed parts of the body like fingers, toes, ears, cheeks and the nose and chin are at risk. Frostbite can cause permanent damage to body tissues, so these injuries should be treated promptly.

The most common symptoms of frostbite are numbness and tingling. Pain and pale skin are also possible.

It’s probably obvious that you will want to warm the affected area when a person experiences frostbite, but it’s important you do so in the appropriate ways. Well-meaning individuals without knowledge of frostbite first aid can actually cause more damage to the skin.

To treat a person with frostbite, first get the person inside. If the feet are affected, avoid having the person walk, as this can further damage injured tissue. To warm the affected tissue, either immerse it in warm water or use your own body heat. You should avoid using a heating pad or anything else that could get too hot, as the person may not feel their skin burning. Contrary to popular belief, you should also not massage the affected tissue; this can cause further damage.

OSHA recommends getting medical help right away if it is possible to do so before trying to warm the frozen tissue, especially if there isn’t a warm area available for shelter. When a frostbitten area is warmed and then freezes again, serious damage can occur, so in these cases first aid should be left to the professionals.


Like frostbite, chilblains affect the extremities. They refer to capillary damage that commonly occurs in the toes, fingers, cheeks and ears. Unlike frostbite, though, chilblains can occur at less severe temperatures as high as 60 degrees. Chilblains occur because of repeated exposure to these temperatures, so dressing for the weather and protecting the extremities is important.

Redness, inflammation, itching and blistering are the symptoms of chilblains, and affected workers may need to visit a doctor for topical medications. In the short term, the skin should be warmed slowly.

Trench Foot

If your whole body is submerged in cold water, you can quickly get immersion hypothermia. If your feet are wet—from standing in cold water or simply wearing wet socks or boots—you can develop trench foot. The same principle about water moving heat away from the body 25 times faster than air applies here.

If someone begins to experience pain, cramps or numbness in their feet or legs and displays symptoms such as reddening of the skin, blisters or bleeding under the skin, the person needs to dry his or her feet as soon as possible. Trench foot is an illness that highlights the importance of proper waterproof footwear or moisture wicking socks during cold weather.

Methods for Preventing Cold Stress Illnesses 

As we’ve mentioned in the past when discussing heat illnesses, it’s often a good idea to use a buddy system so workers check up on each other during extreme weather. This means workers will need to be able to recognize the signs of cold illnesses and know to alert supervisors.

As with heat illness, cold stress can also be avoided by allowing new employees or employees returning to work after time off to acclimate to the weather by taking regular breaks and working up to the amount of time a normal worker would spend in the cold.

Employers should also try to avoid scheduling work for cold times of year if possible, and when outdoor work must be performed in the winter, try to schedule it for the warmest part of the day. Workers should also be given regular breaks in warm areas and have access to warm liquids.

Finally, equipment and protective gear should be adjusted for the weather. If workers use machines with metal handles, those handles should be covered with a thermal insulating material, writes the Canadian Centre for Occupational Safety and Health (CCOHS). Employees should also wear appropriate hats, gloves, boots and layers. Loose layers work best for insulating the body’s core.

Employers should remember, though, that while PPE is necessary, workers might need to adapt to wearing it. CCOHS explains:

Working in the cold requires more energy than in warm weather because the body is working to keep the body warm. It requires more effort to work when wearing bulky clothing and winter boots especially when walking through snow.

Know the Signs and Stay Alert

The arrival of winter is a good time to discuss safety with your workers, as dropping temperatures may require changes to PPE and modifications to work practices. Make sure those who often work outdoors such as snow removal crews, construction crews and public safety officers know the symptoms of cold stress and pay attention to how they feel.

For more information about dressing for outdoor work during the winter, read PPE for the Cold.

Additional Resources