Frigid temperatures might not seem conducive to aquatic workouts, but dedicated open-water or outdoor pool swimmers brave cold weather, and some even seek it out. Your body has some built-in insulation in any fat you have built up, and exerting yourself helps maintain your core temperature, but safe swimming in cold conditions with or without an insulating wetsuit requires careful conditioning and common sense.
Exposure
Cold water robs your body of heat 32 times faster than air that is the same temperature, and water temperatures lower than 32 degrees F can kill in as little as 15 minutes, according to tThe United States Search and Rescue Task Force. Outdoor swimming pools typically heat water to between 78 and 84 F, but wind chill and cold temperatures on deck will quickly lower your body temperature when you exit the water. On especially cold days, keep a wind-proof, fleece-lined swim parka handy to throw over your wet suit for the trip from poolside to locker room.
Cold-Water Swimmers
You can't control the temperature of lakes or oceans, and weather conditions also can change unexpectedly during open-water swims. Distance swimmers extending their swimming season well into the colder months should always swim in a group, and ideally, with people alongside in a boat, stocked with emergency supplies and warm clothing. The thrill some swimmers experience upon successfully completing a cold water and frigid temperature swim puzzles many, yet, once hooked, you might find less-challenging conditions a letdown. Full wet suits or spring suits work for some swimmers, but others feel that the suits only trap cold water and chill them down faster.
Hypothermia
Your ability to preserve core temperature either protects you or leaves you vulnerable to the elements. In "Swimmer" magazine, Alan Steinman M.D., former director of health and safety for the U.S. Coast Guard, explains that hypothermia or effects of low body temperature occurs when your normal core body temperature of 98.6 degrees F falls below 95 F. Between 89 and 95 F, you experience confusion and lose muscle control, shivering uncontrollably. A further drop from 89 F to 82.5 F and you start losing consciousness, and stop shivering at all. Problems with heartbeat and rhythm likely occur, and if your core temperature falls below 82.5 F, death can be imminent.
Adaptation
Elite cold-water swimmers, particularly women, make use of comparatively high levels of evenly distributed body fat. Famed open-water swimmer Lynn Cox boasts a body-fat percentage of 35 percent, as compared with the average 15 percent of land-based, elite female athletes. Mind over matter works for the geographically bi-polar, cold-water swimming veteran, Lewis Gordon Pugh, who uses a process that Tim Noakes, University of Cape Town physiologist calls anticipatory thermogenesis, before frigid plunges to raise his internal body temperature an average of 2.5 degrees F, as detailed in the March 2011 issue of "Swimmer" magazine.
