Per Brian Nystrom:
The result is the opposite of what most would want: the suit is considerably
warmer when out of the water and *less* warm when immersed.

That can easily be minimized by floating horizontal at the surface.
There's little need to stay vertical, anyway.

My contingency plan for having to stay in one place and stay alive as long as
possible is to blow the thing up like the Michelin Man.

Used to do it occasionally for grins/attention with my old Oasis full-neo suit.
The things can get pretty big.
--
PeteCresswell