Tipton recommends five three- to five-minute immersions -- either one a day or stretched out over two to three days.

CNN: Are polar bear plunges good for you?

Tipton, who conducts research on the human body's physiological and psychological response to adverse environments, found that it takes as few as five immersions in icy water for the body to develop a tolerance that can reduce the risk of cold-shock response by half.

CNN: Are polar bear plunges good for you?