Since I have signed up for the winter Alcatraz swim in the "skin" category, the science of cold is back as the focus of my transcendental meditations. For example, when you first jump into the cold water, there is a reflex reaction due to nerves in the face cooling down that causes the heart rate to drop and the breathing rate to significantly increase. Uncontrolled breathing isn't exactly good when you are trying to swim for your life, so how do you control this? Especially considering that this event starts with jumping out of a boat into deep water with no immediate way out. Knowing about the body's physiological responses to cold is a good first step since it will help to alleviate panic.
The last week I had three swims in the cold for 30 to 45 minutes each. There is still about 7 degrees of adjustment for me to make as the water temperature dips down to 48F (9C). Last year I gave up swimming for two months after I did a one mile, 9C swim. The shock was a bit much. This year I have discovered LoneSwimmer.com, which is giving me a lot of info and inspiration that should help me keep going through the entire winter. LoneSwimmer has advertised himself as a "coldologist" with a lot of articles that try to understand what happens to the body in cold environments.