Go jump in a lake. In March.Why would anyone do it if it weren't for charity?We found one guy, an expert nicknamed "Professor Popsicle," who has jump into cold water 40 times as part of his study of the human response to extreme environments. (He says he never has participated in a Polar Plunge-type event, but he has been the emcee for two of them.)Dr. Gordon Giesbrecht
is a professor of thermophysiology at the University of Manitoba in Winnipeg, Canada. His research, which includes pre-hospital care for hypothermia and strategies to escape sinking vehicles, has led to protocols used by the military and law enforcement agencies in Canada, Sweden and the United States.Giesbrecht explained in an email how the bodies of participants in Sunday's Chicago Polar Plunge at North Avenue Beach will react to the near-freezing Lake Michigan water.Giesbrecht: It's known as cold shock response, which includes a few gasps followed by hyperventilation (rapid, shallow breathing). You also feel very cold and uncomfortable.Giesbrecht: The cold shock response usual dies down after about 45-60 seconds. The extreme cold sensation will also change to other feelings like pain or numbness.Giesbrecht: If someone has underlying heart disease, the cold shock response also stimulates the heart and could trigger cardiac arrest. This does happen occasionally in polar bear swims, though rare.
The other risk — if you dive or jump in so your head goes underwater immediately, you could drown if you can't control the gasp of the cold shock response.It is better to wait until the effects die down and then you are more able to hold your breath and put your head under the water if you really want to.Sources: Dr. Gordon Giesbrecht, University of Manitoba, Chicago Polar Plunge @ChiTribGraphics