The coldest air of the season has settled over Mississauga, and the city is asking residents to treat it as a health risk, not just an inconvenience.

Environment Canada issued cold warnings on Friday, Jan. 23, for much of southern Ontario, including the Greater Toronto Area, with wind chill values near -30 to -33 expected. The forecast called for a Friday night low of about -26 C in parts of the GTA, a Saturday high of only -15 C, and the potential for significant snow on Sunday.

In two advisories issued Thursday and Friday, the City of Mississauga laid out what the cold and the shovelling that follows a big snowfall can do to the body, and how to lower the risk.

Frostbite and hypothermia

Frostbite can set in within minutes on exposed skin in severe cold, the city says. Warning signs include numbness, white or yellowish skin and a hard or waxy feel. Severe cases can cause nerve damage.

Hypothermia happens when body temperature drops too low. Signs include shivering, confusion, slurred speech, sleepiness, stiff muscles and loss of co-ordination. The city says anyone with those symptoms after time in the cold needs medical attention right away, and to call 911.

The advice is to dress in three or more layers top and bottom, with a waterproof, wind-resistant outer layer, cover the ears, nose, cheeks, fingers and toes, and change out of damp clothing quickly, since moisture pulls heat from the body.

Why shovelling is hard on the heart

Going from sitting indoors to lifting heavy snow can be risky, especially for people who are not regularly active or have heart or mobility problems, the city says. Shovelling can push the heart rate up faster than a workout, while cold air tightens blood vessels and makes the heart work harder.

Anyone who feels lightheaded, dizzy or short of breath while shovelling should stop immediately.

Finishing the job isn’t worth the risk. Aim for safety, not speed.

— City of Mississauga

The city's tips for safer shovelling include:

  • Talk to a doctor before winter if you have a health condition or are inactive.

  • Warm up with 10 to 15 minutes of stretching before heading out.

  • Avoid caffeine, nicotine and alcohol right before or after shovelling.

  • Wait at least an hour after waking up, since most heart attacks happen in the early morning.

  • Lift with your legs, not your back, and turn your whole body instead of twisting.

  • Take frequent 15-minute breaks indoors and drink water.

Look out for others

Children and older adults are more sensitive to extreme temperatures, and people with heart conditions should seek urgent care for chest pain, shortness of breath or weakness, the city says. It is also encouraging residents to offer to clear walkways for neighbours who are older or have disabilities.

For people without a safe place to stay, the Region of Peel Street Helpline runs 24 hours a day at 1-877-848-8481.