When dressing for the cold, Dr. David Lowe writes, one of the most important things is to keep your extremities warm.

As a family doctor who serves students, nothing drives me nuttier in sub-zero temperatures than walking around the downtown campus of the University of Toronto and seeing people without hats.

Yes, a hat messes up your hair, but have you ever seen what frostbite does to your ears? The discoloration, blistering and swelling aren’t great for your Instagram close-up, let alone your health.

It’s not just vanity that causes people to underdress. At this time of year, I often see students shivering in my waiting room because they haven’t invested in warm winter clothes. Some are newly arrived from warmer countries and genuinely don’t understand the dangers of being improperly dressed in a Canadian winter. (A few years ago, a nurse at U of T even started a coat drive for these students.)

When dressing for the cold, one of the most important things is to keep your extremities warm. Mittens are generally better than gloves because your fingers benefit from each other’s warmth, much like two people huddling together in a sleeping bag. Scarves over the mouth stop heat from escaping, and of course you need a warm hat.

Can’t afford one of those $1,000 down coats? I know they look cosy, but it’s worth remembering that the residents of this city survived without them until recently. Good winter clothes don’t have to be expensive: I believe layers are the best way to keep warm because they insulate you so well. Wear a wool sweater under a regular winter coat, wrap a long scarf around your ears and face, and if money is tight, pick up a pair of inexpensive mittens and boots at a store that serves construction workers, who are outside in all seasons.

Alcohol is another concern in freezing weather: it makes temperature regulation harder for your body. Plus, you’re less likely to dress sensibly if your judgment is impaired. And people who are drunk may miss the early signs of frostbite, which starts with burning and tingling, usually in the fingers, toes, ears or nose. If you get swelling, blistering, discoloration or your pain persists after coming out of the cold, it’s time to see a doctor or nurse-practitioner.

Warming up the affected areas is the first line of treatment. Sometimes we give pain medication and topical ointments and severe cases may benefit from hyperbaric oxygen. Sometimes damaged skin needs to be removed in an appropriate way. But we’ll also want to make sure you’re not developing an infection due to skin damage. It isn’t easy to keep people comfortable when they’re recovering from frostbite, which is why I remind hatless students that you can always fix your hair. Fixing frostbite is not as easy.

Slipping and falling is another danger in cold weather. To make sure your boots are grippy enough, look them up on the website Rate My Treads. And try to walk in cleared areas — there might be ice under that snow. Hold railings on outdoor staircases in case of invisible ice.

In general, the very young and very old are most sensitive to cold and heat because their thermal regulation isn’t as good. People with serious health conditions are also at greater risk: Heart and lung conditions can be aggravated by cold weather, making it harder to breathe. In particular, there are always people with heart conditions who exert themselves too much in cold weather — shovelling snow is a classic example — and end up with heart attacks.

Even if you’re relatively healthy and dress properly for the weather, the terrible cold we’ve just experienced takes a toll on everyone. It takes a lot of energy to face the cold, and the low light at this time of year doesn’t help (which is why vitamin D supplementation is necessary for everyone in a Canadian winter). I think the key is to rest, eat good nourishing food and make sure you’re well hydrated. These things may be common sense, but in the worst of the winter, it can be hard to make the effort to take care of yourself.

Dr. Lowe is the physician-in-chief of U of T’s Health and Wellness Centre.Doctors’ Notes is a weekly column by members of the U of T Faculty of Medicine. Email doctorsnotes@thestar.ca.

Photo credit: RENÉ JOHNSTON / TORONTO STAR