Extreme cold in Canada: How winter temperatures can impact your health — and how to protect yourself

This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis or treatment. Contact a qualified medical professional before engaging in any physical activity, or making any changes to your diet, medication or lifestyle.

Extreme cold is more than just a nuisance, it's a serious risk to your health. Environment Canada is reporting that temperatures could reach approximately -45° C in parts of Saskatchewan, Manitoba, Ontario and Quebec. Weather alerts are in effect for most of the country, with weather alerts in effect not only for extreme cold but for snow squalls, high winds and snowfall.

Winter weather can pose a serious health risk, but extreme temperatures can be particularly dangerous for infants, children, people who work outdoors, unhoused people, seniors, people with chronic health conditions and people living in poorly insulated homes.

From hypothermia to the health risks of shovelling snow, we've gathered a list of common health hazards caused by extreme cold. Keep reading to learn more and to stay safe (and warm) this winter.

Hypothermia

There are reportedly thousands of hypothermia-related deaths in Canada each year. A change of even a few degrees in body temperature (below 35°C) can disrupt organ and nervous system function and constitute a medical emergency.

According to Health Canada, hypothermia occurs in three stages. In the first stage, people will begin to shiver and may experience numbness in their hands as their body temperature drops. They may feel short of breath, have rapid breathing and even begin to feel nauseous. As hypothermia advances, people may feel a warm sensation.

Stages two and three of hypothermia present symptoms that require immediate medical attention since people with hypothermia can become unconscious, experience seizures, have slowed heart and breathing rates and can experience cardiac arrest.

Signs of hypothermia in advanced stages can include:

• Confusion

• Loss of coordination

• Drowsiness

• Slurred speech

• Pale, grey or blue skin

People with hypothermia may shiver uncontrollably; however, in some cases, shivering stops in people with extremely low body temperatures.

If you suspect someone has hypothermia, call 911 and seek immediate medical help. For early stages of hypothermia, relocate to a heated area to gradually increase your body temperature. Health Canada recommends drinking warm, sweet liquids, removing and replacing any wet clothing and keeping your muscles moving.

How to prevent hypothermia

The best way to prevent hypothermia is to dress appropriately for the weather. Opt for warm layers, socks, a wind-resistant jacket, gloves, scarf, hat and face covering to protect your ears and nose.

If possible, avoid going outside in extreme cold temperatures; hypothermia, frostbite and windburn have a greater chance of occurring when temperatures fall below -27°C. Young children and people 65 years and older can lose body heat very quickly and should limit exposure to cold temperatures whenever possible.

Heart health and extreme cold

Winter weather poses serious health risks for people with cardiovascular disease. Cold weather causes our hearts to work harder to maintain body temperature. According to the Canadian Heart and Stroke Foundation, people with cardiovascular disease or coronary heart disease are at an increased risk of accidental hypothermia and may experience chest pains when they're in cold weather or after exerting themselves.

Additionally, shovelling snow or even walking in snow can put extra strain on the heart. A 2017 study published in the Canadian Medical Association Journal showed a link between heavy snowstorms and heart attacks that either result in death or hospitalization. Between 1981 and 2014, researchers in Quebec found that 65,000 people died from heart attacks, and 128,000 were hospitalized during or after heavy snowfalls.

Signs of heart attacks can include:

• Chest pain

• Pressure in the chest that comes and goes

• Tight feeling in the chest

• Shortness of breath

• Pain radiating towards your neck and arm

• Feeling lightheaded or dizzy

• Stomach pain

• Cold sweats

• Nausea or vomiting

• Numb or pinching feeling in the arm

• Neck, jaw or upper back pain

• Heartburn or indigestion

The short bursts of energy required when shovelling snow can pose serious health risks for people with heart issues. To prevent injury, people should stretch beforehand and take frequent breaks while shovelling snow. If you know that you have a heart condition or heart disease, consider asking a neighbour or family member to shovel for you.

Cold weather and stroke

Aside from heart attacks, extreme cold increases the risk of stroke. The British Heart Foundation notes that cold weather can cause blood to thicken and "become stickier" and more likely to form clots. Staying warm by dressing in layers and wind-resistant clothing and limiting your time outdoors is important for people who are at high risk for heart attack and stroke.

Frostbite

People are at risk for frostbite whenever temperatures drop below 0°C, which makes extreme cold very dangerous for exposed skin. As the temperature lowers, blood vessels close to the surface of the skin constrict to help preserve our body temperature.

When skin is exposed to the cold for a prolonged period, it freezes, and blood flow becomes restricted, causing frostbite. Our hands, ears, nose and toes are at an increased risk for frostbite — even if you're wearing winter clothing and outerwear — since they lose body heat quickly.

Signs of frostbite can include:

• Numbness or tingling

• Red, blue, white, grey, purple or brown patches of skin (colour varies by frostbite severity)

• Stiff joints

• Pain

• Blistering once the skin has warmed

• Cold, hard or waxy-looking skin

Frostbite can be difficult to detect on darker skin tones. According to The Cleveland Clinic, people may be unaware that they have frostbite because of numbness.

Severe or deep frostbite can cause permanent nerve damage. In some cases, frostbitten skin can break and become infected; amputation may be required to prevent infection (gangrene) from spreading.

Unhoused people are at an increased risk of frostbite. In 2023, Edmonton experienced an increase in frostbite-related amputations due to the city's growing unhoused community, which lacks adequate resources. People with chronic health conditions, like diabetes, Raynaud's syndrome and peripheral vascular disease, also have an increased risk of frostbite, as well as people who smoke or take certain medications like beta blockers.

While mild cases of frostbite can be treated at home, seek immediate medical attention if you suspect you have moderate or severe frostbite.

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