Torso Heating of Divers in Cold Water

Abstract

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. Seven U.S. Navy divers wearing semidry suits were submerged in 7.2 degrees 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. 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. 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.