Life jacket design affects dorsal head and chest exposure, core cooling, and cognition in 10 degrees C water.

Purpose: Personal floatation devices (PFDs) differ in whether they maintain the head out of the water or allow the dorsum of the head to be immersed. Partial head submersion may hasten systemic cooling, incapacitation, and death in cold water.

Methods: Six healthy male volunteers (mean age = 26.