I get this question a lot and here is the answer:
“Until pouring ice cold water over your head is the best idea you’ve ever heard.”
There are far too many factors that negate a specified time, such as:
- When you last ate.
- Your body weight.
- Your level of hydration.
- Your individual tolerance of extreme temperatures.
If anything, I would argue that timers can be dangerous, so don’t use them at all. Wait until pouring ice cold water over your head is the best idea you’ve ever heard.
Note: substitute a jump in the lake or a roll in the snow when applicable.