Bumped into a article about a cold water study that piqued my interest: A must read for any of you "polar swimmer cubs" thinking of taking the plunge tomorrow. Be prepared.
By the way a polar bear swim for me without a wetsuit on is 65-degrees! Any temp lower than that is not a water temp, it's lousy ice skating.
"... Still, the excessive breathing can change your blood chemistry," said Dr. Thomas Traill, a cardiologist at Johns Hopkins Hospital. "Breathing too much can draw carbon dioxide "off" your bloodstream, which changes the pH of your blood and decreases its levels of ionized calcium.
"When ionized calcium goes down, muscle membranes don't function properly," Traill said. As a result, muscles quickly weaken or can even cause a swimmer to become temporarily paralyzed, he said. "You hear every now and then of people falling out of boats and drowning in cold water when they're only a foot from the dock," Traill said, attributing this to the uncontrollable hyperventilation. "The important thing for the polar bear swimmers is that they shouldn't do this alone, and they shouldn't do it out of their depth. ..."