How we might prepare for the Black Hole: Cold Water Training by Stew Smith There is an argument as to whether some people are genetically wired to handle colder temperatures, or whether one must build stamina for lower temperatures by training in colder environments (water or land). I believe it is a little bit of both. When I was attending SEAL Training, the water off San Diego was brutal to new recruits. Typically, water temperatures were (at best) 69 degrees during the warmest part of the summer and dropped to in the low 50's during the winter. Then in dive phase, at about 15 feet underwater, you would hit a thermo-cline and water temperature was in the low 40's. That was when BUD/S got cold, especially during a winter dive phase. /// People often ask me, "What is the best way to train for the cold water at BUD/S? Do I take ice baths, cold showers, or sit in a pool for hours?" For me, what I think helped me was hours of surfing/body surfing a few years prior to BUD/S. Physical training such as swimming/surfing /playing in water temperature near those of San Diego is what I would recommend for short periods of time. Do not let yourself get to a point where you are shaking uncontrollably or (especially) not shaking at all, as you can die if you play around too much with your core temperature. Therefore, I do not recommend placing ice in a bath tub and dropping the water temperature to arctic levels. Colder showers are OK if you like mild torture, but training for cold water-endurance by yourself can be dangerous.