Use caution at polar bear dips, Brock professor warns
Stephen Cheung has never taken part in a polar bear dip despite years of research into the effects of extreme temperatures on the human body.
“I experience enough cold in my everyday research,” said the Brock University professor in the kinesiology department.
Also the Canada research chair in environmental ergonomics, Cheung spent nine years at Dalhousie University in Halifax, at the edge of the North Atlantic, researching offshore marine survival.
He’s carried on that cold-water research at Brock, looking into the effects of extreme heat on the human body as well.
With a polar bear dip scheduled for Dec. 7 at Bay Beach in Fort Erie, Cheung spoke about potential risks for participants who decide to take a plunge into the chilly waters of Lake Erie.
“For healthy individuals, it’s fine, as long as it’s a well-supervised event.”
For people with heart problems, including high blood pressure or heart disease, something like a polar bear dip that highly stresses a body is not a good idea. “Your heart rate increases rapidly.” It can go from resting at 50 to 70 beats per minute to 140 to 150 beats per minute in a very short amount of time.
People experience what’s called a coldshock response when they hit the cold waters in a polar bear dip and that causes a flight or fight response. Cheung said the shock can cause a person to hyperventilate as well.
Once in that cold water, though, a person’s breathing and heart rate begins to calm down after a few minutes.
But staying in too long can cause the body’s core temperature to drop and lead to the onset of hypothermia.
“Wearing a dry suit in water your body will cool down slowly, wearing shorts and a T-shirt you’ll cool down rapidly.”
In addition to the water temperature, current can cause a person to lose heat faster as it passes by a person’s body.
Cheung warned against people consuming alcohol before a polar bear dip.
“Your judgment may be impaired. A common reaction is that it will make you feel warmer because your skin’s blood vessels are opening. It’s that warm flush you feel.”
Heat loss occurs more rapidly with warm blood so close to the surface of the skin.
Standing around in a cold, wet T-shirt and shorts can also be a problem. The wet materials draw heat from a person’s body, said Cheung, adding people should dry off right away.