Torso heating of divers in cold water

Introduction: Cold water immersion could compromise both the effectiveness and safety of a diver. This paper reports an evaluation of the utility of providing external heating to divers in cold water. Methods: Seven U.S. Navy divers wearing semidry suits were submerged in 7.2°C water for 2 h. In the heated condition, a total of 35 W was delivered to each of four heating pads (total area 2477 cm2) placed on the torso of the divers. In the unheated condition, the participants received no external heating. Results: The participants believed they were more comfortable in the heated, than the unheated condition. However, objective data did not support this perception. In fact, heating the torso had a significantly detrimental effect on the body's thermoregulatory ability, and lacked a positive effect on manual dexterity. Cognitive test performance was not affected by the exposure. Discussion: Heating the torso did not have a positive effect on diver performance. Moreover, heating the torso of a diver may actually increase susceptibility to hypothermia.