Great post! I love the fact that you brought the science and the interesting facts on top of the beautiful pictures and the person story. It was a really entertaining read :D
Will you swim in a cold swimming pool?
Sure, I'm not a very good swimmer but I don't mind cold water, especially in the summer.
Have you ever been in very cold mountain water?
I've been barefoot in really cold mountain springs. The water there is just a few inches deep but it is extremely cold, nothing like a cold swimming pool or cold sea water. Your feet basically start to hurt pretty quickly in there and it was not a sensation I could actually get used to, it was a sensation I could bear with for some time. But after you take your feet out and dry them, the effect is actually refreshing and nice :)
Do you ever take cold showers?
I sometimes do. I alternate between hot and cold water from time to time, just to keep myself sharp and refreshed. Generally speaking, when I shower, most of the time I use water that is cool rather than hot or warm, but not absolutely cold one.
There is certainly a pain threshold that needs to be passed and the feet is just the beginning. Once the cold touches your jewells you could be in for an experience. I'm so happy to read about your mountain water experiences.
I regularly swim in 20 degree water so I am somewhat trained!
Ouch, the jewels :P
I feel the mountain water was colder than 18 degrees Celsius which is a sea temperature I have swam in without the same pain. But I have no clue how cold the mountain spring was as having your feet in and the rest of your body out can probably create a big apparent difference. Also when you are swimming, you can warm yourself with movement while there is no real physical strain when you are just keeping your feet in the water.
I think I have experienced 15 degrees in the Baltic see in Estonia once, but I honestly don't remember the sensation that well and I think I was lucky to fall upon some weird warmer stream or something, so I have no clue what the actual temperature was and I couldn't use it as a comparison.
Well if you were tingling afterward it was cold! Lots of fun.