[MR] The cold Water Consumption Dilemma-A question

[Oxford, David]

>> but I'm not so sure I would ever dunk anyone having
>> problems with lack of water/heat in ice water.

A wise decision.  Specifically, do not dunk your head and upper body first into
very cold water, particularly if you are hot.  Doing so can trigger a sudden
over-stimulation of the vagus nerve which can, in some people, almost instantly
cause your heart to stop.

My wife's uncle died that way.  He was a healthy, fit US Navy sailor in his
early twenties... dove head-first into some cold water when he was hot and was
dead before he returned to the surface.  Postmortem confirmed he died of cardiac
arrest.  Nobody would have thought he was prone to that, so you never know.
Best not to chance it.

Bryan