Until your core temperature drops and hypothermia sets in.
“Until your core temperature drops and hypothermia sets in.”
You’d be surprised just how far you can push the limits of cold.
Anyone will eventually succumb in cold enough water. Thats true and likely part of the reason for the training. Repeated exposure to cold water teaches your body to restrict blood flow to the surface and reroute to/reserve the warmth in the core. When you get used to it your body instantly makes the switch and you can stay in 40-50ish water for a very long time.