Diver Performance and the Effects of Cold

The capability of divers was tested by a test battery composed of tests of tactile sensitivity, grip strength, manual dexterity, tracking, assembly of a structure by groups, mental arithmetic, symbol processing, simple problem solving and memory. At a diving tower and a flooded quarry, test data were collected for performance on dry land (control) and at water temperatures between 44° and 72°F. A limited sample of post-dive urine temperatures and skin temperatures were recorded. Divers wore a complete 3/16” wet suit, except that, during the tests, the hands were bare. The results show: hand impairment—losses in tactile sensitivity, grip strength and manual movement; the losses were proportional to degree of cold and exposure time; the losses follow a similar course to skin temperature decrease and hence are considered due mainly to peripheral physiological attenuations; psychomotor impairment—losses in manual dexterity, tracking and group assembly were proportionate to water temperature; mental impairment—losses in mental capability occurred in those cases where the task required intense attention and involved considerable short-term memory; “blocking” effects occurred at the lower temperatures. The causes of the losses in capability are discussed in terms of peripheral and central impairments, in terms of “water” effects and “cold” effects, and in terms of a hypothesis that immersion in cold water serves to distract the diver. Some practical and theoretical implications of the study are reviewed.