We attended a presentation last evening about cold water immersion. The speaker was Randall Feesler. Watercraft Office with ODNR in Akron, Oh. Mr. Feesler was part of a group that was filmed in the second video in frigid Lake Erie water. The instructor is Dr. Giesbrecht also known as "Professor Popsickle".
With early spring paddling already here these videos might give you just a bit more respect for cold water. It may also be helpful to recognize what that paddler that just went for a swim is going through.
Some of video this made me uncomfortable just watching! -Ken
Cold Water Boot Camp
https://www.youtube.com/watch?v=J1xohI3B4Uc
Beyond Cold Water Boot Camp
http://www.youtube.com/watch?v=nwETEkmVAeE