Online CPR Certification Blog

Cold Stress Symptoms, Causes & Prevention

Cold stress occurs when workplace conditions expose an employee to temperatures low enough to cause excessive chilling or freezing of the body.

Cold stress symptoms can lead to serious medical problems, such as trench foot, frostbite, and hypothermia. The elderly, the very young, and people with health problems are especially vulnerable.

What Causes Cold Stress Symptoms?

Any condition that causes prolonged exposure to cold temperatures can lead to cold stress:

• Working in cold rooms or freezers
• Wearing wet clothes in cold temperatures
• Working outdoors in the winter
• Falling into cold water

Cold stress is a danger for anyone who works outside in the winter, on a production line, or in a walk-in freezer or refrigerated room.

Understanding Cold Stress: How it Happens

The human body loses heat through four different mechanisms: conduction, convection, radiation, and evaporation. Conductive heat loss is the transfer of body heat directly to a cold surface.

Convective heat loss is the transfer of body heat from air movement (wind), removing warm air from around the skin surface. Radiant heat loss is the transfer of body heat from exposure to cool surfaces that radiate cold temperatures. Finally, evaporative heat loss is the transfer of body heat through the evaporation of sweat during work or physical activity.

Causes of Cold Stress

Cold stress symptoms can occur when workers are exposed to:

• Low temperatures (below 32 degrees F)
• Winds that create “wind chill” (which speeds the rate at which exposed skin loses heat) or Wind speed (above 20 miles per hour)
• Wetness/dampness (which reduces the insulating value of clothing by reducing its ability to trap warm air next to the skin)

Other factors may include:

• Body size, age, and metabolism
• Level of activity
• Body fat levels
• Degree of clothing insulation

People with poor circulation may not realize they are developing cold stress because they may not feel their fingers or toes getting very cold due to nerve damage.

Types/Stages of Cold Stress

The human body depends on a fairly narrow temperature range to function. When that range is disturbed, you begin developing cold stress symptoms.

1. Shivering

Image Alt text: some cold stress symptoms

The first stage of cold stress is shivering, which is actually a good sign. It’s your body’s way of generating additional heat by working your muscles faster than normal. However, if you stay out in the cold too long, that heat generation can’t keep up, and you’ll start developing hypothermia.

2. Hypothermia

Hypothermia is when your core body temperature drops below 95 degrees Fahrenheit (35 degrees Celsius). This can be fatal if it isn’t treated quickly because your organs will start shutting down. Remember that even if someone seems unconscious or dead, they might still be alive and able to be saved by rapid medical attention.

3. Frostbite

Frostbite occurs when skin tissue freezes. It most often affects feet and hands, but any skin exposed to freezing temperatures can be affected. Frostbite causes numbness and pain at first, but those symptoms are often followed by the total loss of feeling in the area affected by frostbite. In severe cases, frostbite can lead to gangrene and even amputation of the toe.

4. Trench Foot 

Trench foot is caused by prolonged immersion in cold water (50° F), which can result in tissue damage. The condition can develop in just a few hours if feet are wet and exposed to cold temperatures.

As soon as possible, after developing symptoms of trench foot, remove the wet socks and shoes and dry your feet. If possible, walk around for a bit to help warm your feet. If you must continue walking, put on dry socks and shoes.

5. Chilblains

Chilblains are deep skin sores that appear on hands and feet. They can cause swelling, itching, burning, and pain. If care is not taken to re-warm the area, chilblains can progress to blisters or ulcers.

Cold Stress Symptoms: How Different Types of Cold Stress Manifest

The body’s normal response to cold is to reduce blood flow in the extremities and maintain core body temperature. Cold stress occurs when the body’s control mechanisms are overloaded and cannot maintain core body temperature.

The signs and symptoms of cold stress vary depending on the severity of exposure but can include:

• Mild: shivering, numbness, goosebumps
• Moderate: stiff muscles, inability to perform fine motor skills, loss of coordination
• Severe: confusion, irrational behavior, frostbite, hypothermia

Signs and Symptoms of Frostbite 

Fingers and toes are most susceptible to frostbite, especially if they are wet.

Warning signs include:

• Stinging,
• prickling or aching of the skin
• Numbness of the skin
• A  white or grayish-yellow skin area.

If you suspect frostbite, get medical help immediately and do not rub or massage the affected area.

Signs and Symptoms of Hypothermia

Hypothermia occurs when the body loses heat faster than it can produce it.

Warning signs include:

• Uncontrollable shivering, 
• memory loss,
• disorientation,
• incoherence,
• slurred speech,
• drowsiness and apparent exhaustion.

If you suspect hypothermia, seek medical help immediately and begin warming the person slowly by wrapping them in a blanket or moving them indoors to a warm environment until professional help arrives.

Signs and Symptoms of Trench Foot

Trench foot is a condition caused by the prolonged exposure of the feet to damp, unsanitary, and cold conditions.

The symptoms of trench foot include:

• itching,
• pain,
• tingling, and
• numbness in the affected areas.

As the condition develops, swelling takes place that may result in blisters, warmth, and redness.  If not treated immediately, trench foot can result in gangrene and tissue death.

Risk Factors for Cold Stress 

Some people are at higher risk than others of developing cold stress. Conditions that make you more vulnerable include:

• Age (either very young or old)
• Being overweight or underweight
• Poor physical condition and lack of fitness
• Certain illnesses and diseases

Cold stress symptoms occur when the body can’t maintain its core body temperature and can be caused by exposure to extremely cold air or water, or wind.

1. Pre-existing health problems

There are a number of health conditions that can increase someone’s chance of getting cold stress. These include diabetes, hypertension, hypothyroidism, and cardiovascular disease.

2. Not wearing proper clothing

Those who are not wearing proper clothing for cold weather conditions are at a higher risk for cold stress.

3. Dehydration & malnutrition

People who suffer from dehydration and malnutrition are also at increased risk.

4. Slipping into ice 

Accidents such as slips and falls are common among people who work outside in the winter. If someone falls through ice into the water, they can get wet and lose body heat quickly, which could lead to hypothermia. Be sure to take precautionary measures if you or your workers will be working in the elements this winter!

Tips to Prevent Cold Stress

Cold stress is a common problem for outdoor workers. Cold stress can cause conditions such as hypothermia, frostbite, trench foot, and chilblains.

1. Dress properly

The key to preventing cold stress is to dress properly.

When you’re outside in the cold, you should wear at least three layers of clothing:

• an inner layer of wool,
• silk or synthetic (polypropylene) to keep moisture away from your body;
• a middle layer of wool or synthetic to insulate even when wet;
• and an outer wind-and-rain-proof layer that allows some ventilation to prevent overheating.

Make sure the outer layer’s hood fits well underneath your hard hat and face shield or safety goggles. Wear thermal underwear under your work clothes for an extra layer of protection. Wear waterproof boots with insulated liners.

Some boots are made with special materials that retain heat better than leather. Keep your feet dry and change socks if they get wet.

2. Take breaks– let your body warm up

When working in the cold, take frequent breaks in warm, dry shelters to allow your body to warm up. Drink warm, sweet beverages (sugar water or sports-type drinks) and avoid drinks with caffeine (coffee, tea, or hot chocolate) or alcohol.

3. Avoid overheating your body

Avoid getting overheated, which will increase the risk of sweating and lead to a loss of body heat.

4. Eat well

Eat well-balanced, regular meals to give you the energy needed to stay warm and help your body’s metabolism function properly.

5. Take plenty of water

Lastly, drink plenty of water; avoid beverages that contain alcohol or caffeine since they cause your body to lose heat more rapidly.

First Aid Assistance for Cold Stress

A person with frostbite on the nose, cheeks, or ears (or any other part of the body) should be taken to a medical facility as soon as possible. The goal is to keep the patient from moving until a medical professional can rewarm the affected area.

First Aid Treatment for Cold Stress

Here are some first aid treatment tips to assist cold stress victims:

1. Protect the injured person from further cold exposure; take them out of the cold or wind.
2. Seek medical help immediately, as frostbite can cause permanent tissue damage.
3. Do not rub or massage the affected area in an attempt to warm it up; this could cause more tissue damage.
4. Remove wet clothing and replace it with dry, warm layers of clothing if available.
5. Warm frostbitten areas using warm water, body heat (place an unwounded part of your body over a frostbitten area), or heated blankets if available.
6. Keep one part of the body warm while another is being warmed in a process called regional rewarming or regional thawing; this prevents shock and lowers the risk for hypotension (low blood pressure).

Lastly,

Never use direct heat such as hot water, stoves, or radiators to rewarm frostbitten fingers, toes, or some other body parts, as this may burn the victim’s skin.