Come New Year's Day, many Canadians will mark a fresh start by taking part in the bone-chilling polar bear swims and dips held across the country.
Whether you are challenging yourself as a new year's resolution or raising money for your favourite charity, there are safety tips to keep in mind before you make the plunge.
Stephen Cheung, a kinesiology professor at Brock University who also holds the Canada Research Chair in environmental ergonomics, studies how humans adapt to extreme environments. He has helped firefighters, Canadian Forces soldiers and coast guards develop protective clothing to adapt to extreme heat and cold.
"Overall, [polar bear plunge] is fun, it's safe, especially in an organized situation where there's first aid," said Cheung, whose work with extreme temperatures has earned him the nickname "Dr. Freeze."
He said there are steps participants can take before, during and after the event to protect themselves and ensure a fun, safe start to the new year.
Before: mentally prepare yourself
Participants should mentally brace for the upcoming "cold shock response," which is triggered when the skin temperature drops rapidly as they make the plunge, Cheung said.
Participants might experience more rapid breathing and difficulty holding their breath. Their heart rate could also go from the resting normal of about 60 beats per minute to up to 140 beats per minute.
"So the first thing is to be aware this is going to happen, so you can mentally prepare yourself," Cheung said.
For those who would like to minimize the stress on the day of the event, they can try taking cold showers for a week beforehand to familiar their bodies with the cold.
"But in a sense, for polar bear jumps, that kind of takes the fun out of it," he said.
During: dive in or take it slow?
Cheung said a common question participants have is whether they should dive right in or gradually lower themselves into the water. He prefers the latter to save "the mental anxiety."
"Personally, I would just jump in and get it over with … splash around and get the heck out," he said.
However, Cheung noted that scenario only applies to recreational events like a polar bear dip. In a real-life survival situation, such as during a boating accident when the boat is sinking, people should get into the water as gradually as possible.
"I want to do everything I can to minimize this cold shock response," he said.
After: dry yourself
A common misconception people have, Cheung said, is that splashing around in cold water for a few minutes can cause hypothermia. In fact, even for a lean person, it takes about 30 to 60 minutes before the drop in body temperature becomes dangerous.
That being said, participants should change out of their wet clothes and dry themselves right away after they come out of the water.
"Especially if you're next to Lake Ontario [when you come out] or whatever and you have the cold wind blasting against you. That's when you are going to start losing heat quite rapidly," he said.
Cheung said he doesn't recommend those with pre-existing heart conditions to take part in the polar bear plunge, as well as those who are not used to higher heart rates — people who are chronically sedentary, for example.
Participants also shouldn't consume alcohol before making the plunge. Not only does alcohol impair judgment and motor coordination — thus making it more difficult to get out of cold water — it also opens up blood vessels.
"That’s going to cause your body to lose heat a lot more rapidly," he said.
Cheung added that although he is not opposed to people participating in an organized polar bear plunge event, he warns against individuals holding a spontaneous jump.
"What I'm really concerned with is a couple of guys up at their cottage and decide, 'Well, it's new year and let's dig a hole in the ice and jump in,'" he said.
Cheung explains that there is a higher chance these people are under the influence of alcohol, and it is "extremely difficult " to get out of a hole in the ice.