Extreme Cold: How to Prevent Cold Stress When Working Outdoors

Workers in construction, agriculture, security, and commercial fishing that work in extreme weather conditions or in cold environments are at increased risk of developing cold stress.

Developing cold stress can have a serious negative impact on your health, and can even result in death. A Public Health England’s Cold Weather report showed that extreme weather has a direct effect on the incidence of heart attack, stroke, flu, respiratory disease, falls, injuries and hypothermia. In the last 5 years alone in the UK, there were also a total of 168,000 cold-related deaths, many of which could have potentially been prevented.

When outdoor temperatures drop below 5-8°C respiratory and cardiovascular health problems can occur and as the temperature continues to drop the risk of death and illness increases. These shocking facts and figures make it crucial that those working outdoors or having to face extreme weather conditions are properly prepared in terms of awareness and protective clothing.

1. What is Cold Stress?

Cold stress occurs when the body is subjected to low cold temperatures for extended periods of time. Essentially, the body loses its ability to maintain a core body temperature, which can cause serious illness and even death.

Working in cold conditions for long periods or with inadequate protective clothing forces the body to work much harder than it normally would to maintain a healthy body temperature. Conditions such as hypothermia and frostbite may arise from this.

The term ‘cold stress’ is essentially a blanket term encompassing any illness caused by the body being unable to maintain a healthy temperature after repeated exposure to cold working environments.

It isn’t just cold that causes stress to occur, however. The four factors responsible for cold stress are exposure to cold water, dampness, high or cold wind and cold temperatures.

So moderate weather, combined with cold winds and heavy rainfall may also cause cold stress, warmer weather can cause other stresses, see our guide to Heat Stress.

2. Types of Cold Stress

Common ailments caused by cold stress include hypothermia, which occurs if the body’s temperature drops significantly after exposure to extreme cold.

Frostbite, another form of cold stress, develops after a person comes into contact with cold materials like ice or frozen metal. This can cause severe skin irritation, as well as numbness, blistering and discolouration.

Trench foot, so named for the high number of casualties it caused during the First World War, is another condition caused by cold stress. It occurs via extensive exposure of the skin to wet and cold environments. In extreme cases, it can lead to gangrene.

Chilblains are also caused by cold stress (though they can sometimes occur as a result of humidity). Essentially, cold environments force the blood vessels to shut down, which can lead to skin problems such as blistering, inflammation, discolouration and even bone fractures.

3. Symptoms of Cold Stress

The following are a few symptoms to watch out for. If you spot anybody displaying these symptoms, they should be removed from the cold environment at once. According to Idaho State University.

In all cases, medical professionals should be summoned to the scene at once. See below for advice on how to treat these conditions.

4. What Contributes to Cold Stress?

Human beings rely on behavioural thermoregulation to keep warm.

What this means is that, when faced with bitter cold or inhospitable conditions, we instinctively seek shelter and clothing in order to keep ourselves safe.

In short, we are simply not designed to endure prolonged exposure to the cold.

We are an intelligent and resourceful species, which has mastered many methods of staving off the cold, but in the end, we are still reliant on external technologies, such as warm clothing in order to keep warm..

5. How the Body Reacts to Cold Stress

When the body finds itself in a cold environment, it devotes an enormous amount of energy to steadying its core temperature and keeping itself warm. It does this, quite simply, to stay alive.

When the cold sets in, the body begins by constricting blood vessels, thereby shifting blood flow (and thus, heat) away from extremities such as fingers and toes, hands and feet, or arms and legs. It then directs more blood towards the chest and abdomen in order to warm the core.

When it can no longer constrict the blood vessels, the body begins to shiver in an attempt to maintain body heat.

Cold weather will also cause the body’s metabolism to speed up, as ‘warming up’ activities such as shivering require a greater caloric intake.

Prolonged exposure to severe cold has been linked to respiratory problems, musculoskeletal disorders, cardiovascular disease and various skin conditions. It can also cause blood thickening, which dangerously increases blood pressure, increasing the risk of developing (or aggravating) various pulmonary disorders.

6. Who is at Risk?

Anybody spending a reasonable amount of time in a cold or damp environment is at risk of developing some form of cold stress. People who are employed to spend long periods of time in the cold without breaks are especially vulnerable.

Outdoor workers that have become accustomed to working in inhospitable conditions are often among those most at risk, though they are also among the least likely to notice the symptoms.

Older people are slower to generate heat than younger people. Accordingly, they are also at risk of developing conditions related to cold stress and further on PTSD.

People with chronic obstructive pulmonary disease (COPD), or indeed any heart-related health issue, are at a greater risk when faced with cold weather.

7. Preventing Cold Stress

Fortunately, there are preventative measures you can take to protect yourself and your staff from cold air temperature. Here are a few of them.

Wear at least three layers of clothing at all times. These should consist of a durable, yet ventilated outer layer to act as a windbreak, a middle layer of wool of fleece to absorb sweat and act as insulation and a well-ventilated inner layer.

Loose clothing is generally more insulating than tight clothing, which can also restrict blood flow, so it is generally better for keeping you warm. Always bring extra clothes to work (or store some there).

A lot of heat can escape from the top of the head, so thermal gear is also important. Your ears, face, hands and feet should always be protected. In extreme cases, eye protection may be required.

All footwear must be waterproof and properly protective against the elements, especially damp.

Where possible, try to schedule outdoor shifts for the middle of the day. Morning and night are the coldest parts of the day, so try to avoid being outside or sending other people outside for too long during this time. Limit the time spent outside, either by shift swapping with colleagues or considerate scheduling.

If you are an employer, don’t be cheap. Use relief workers or bring in extra staff to help complete the more complicated jobs. Don’t try to get a long and difficult outdoor job done with a skeleton staff, to do so presents too great a risk.

Keep up to date with weather reports, wind chill factors and other related data. Try to note these things as far in advance as possible and schedule accordingly.

Be aware of the symptoms listed above. Know what you’re looking out for and keep an eye on your colleagues/staff, especially those who are older or have heart problems. Listen to their concerns and take them seriously. Learn the symptoms of exhaustion and fatigue, both in yourself and others.

8. Treatment of Cold Stress

Other conditions that are sometimes included under the banner of cold stress injuries include frost nip, which occurs when the top layers of skin become frozen. It can be treated by slowly warming the affected area. In general, frost nip is treated similarly to frostbite, and comes with some of the same risks.

There is also a condition known as Cold urticaria, a reaction to the cold that presents via hives, wheals, dyspnoea (shortness of breath/breathing difficulties), headaches, vertigo or even anaphylactic shock.


Anyone experiencing the symptoms of hypothermia must be removed from the cold and placed somewhere warm. Their wet/cold clothes must be replaced with warm/dry ones and they should be put under as many blankets as possible. Hot drinks such as tea, coffee, warm milk or cocoa may also help, but you should never try to force liquids into an unconscious person. If the person has no pulse, you need to begin CPR immediately.


A person suffering from frostbite symptoms must be instantly removed from the cold and placed somewhere warm. Try not to let them walk on frostbitten feet, as this can worsen the damage done. Once in the warm, the affected areas should be immersed in warm (not hot) water or otherwise gently heated up. Do not massage or rub the affected areas, as again this can worsen the condition. Avoid heating pads, fireplaces, stoves or radiators, as frostbitten areas are easily burned.


The best way to treat trenchfoot symptoms is to retire to a safe, warm space and carefully remove the person’s boots or footwear and socks. Be sure to dry the feet carefully and thoroughly and ensure that the person avoids walking on their feet.


If someone you know is affected by chilblains, you must ensure that they avoid scratching, even though the skin may be greatly irritated. The afflicted area must be slowly warmed up, while corticosteroid creams are applied to relieve itching and swelling. Ensure that blisters and sores are kept clean and covered. Avoid caffeine, but feel free to give them ibuprofen or paracetamol to numb the pain. Chilblains usually clear up on their own after a period of time.

9. Other Cold-Related Illnesses

Drink warm liquids regularly and provide them to others. You’ll be amazed how refreshing a warm cup of tea or coffee can be to an outdoor employee on a cold day. It is advisable to avoid too much caffeine, however, so decaf may be the best option.

Ensure that break/staff rooms are always kept warm and are well stocked with warm, high calorie foods.

Provide education or training on the hazards of working in the cold. Always ensure that there are trained first aiders on site.

Always avoid touching very cold or frozen objects with your bare skin.

10. Cold Stress & UK Law

In the United Kingdom, the Health & Safety Executive (HSE) regulates health and safety law and concerns in the workplace.

The Workplace (Health, Safety and Welfare) Regulations act 1992 stipulates that employers must provide a ‘reasonable’ temperature for their respective workplaces, ensuring that they are neither too hot nor too cold. It should be noted, however, that there are no maximum or minimum temperature set by this legislature.

The Management of Health and Safety at Work Regulations act 1999 requires employers to conduct a risk assessment of the working conditions faced by their staff.

Under UK law, all employers have a duty to ensure that their employees are not exposed to unreasonable temperatures during their respective shifts. Rest breaks and facilities must also be provided. This includes access to warm drinks and break rooms if the workers are being exposed to cold climates. Education and training should also be provided where it is needed.

The Health for Work Advice line may be reached at 0800 778 844. Further legal advice can be obtained here, along with suggestions on how best to keep yourself and your staff safe.