Thanks for the link to the loneswimmer.com website. (I had never heard about it before) It's very clear that I am just a mere dabbler with this cold water stuff...
I haven't attempted to document how long it has taken for me to warm up after various temperature and duration swims. I just know that sometimes various parts of my body surface can be cold to the touch several hours afterwards.
In contrast, the glow and stimulation from a good cold swim can last for a day or two. I feel that there must be some beneficial effect to one's health, such as immune system stimulation, or something.
"Loneswimmer" describes a lot of the post-swim benefits quite eloquently.
Some things I thought of after posting my thoughts yesterday:
I don't go into the water with a pre-set distance in my mind; I just swim as much as feels "enough" on that particular day. I carefully observe landmarks at my turn-around points, and then measure my distance by using Google Earth after I get home.
Also, I never measure the water temperature BEFORE swimming - I really DON'T WANT TO KNOW what the numbers are in advance. AFTER each swim, I get my thermometer out of my swim bag and go back into chest-deep water to take a reading.
Although most of my swims in the really cold water are fairly short, I have to admit that the challenge of The Ice Mile is starting to gnaw on me....