Effect of heat and chemical protective clothing on cognitive performance

This study examined the effects of heat on the sustained cognitive performance of sedentary soldiers clad in chemical protective clothing. There were 23 men trained for 2 weeks on selected military tasks. Then they performed the tasks for 7-h periods on 4 successive days (Days 1 and 3 = 21.1 degrees C, 35%rh, battle dress uniform; Day 2 = 12.8 degrees C, protective clothing; Day 4 = 32.8 degrees C, 61%rh, protective clothing). After 4-5 h in the heat wearing protective clothing, the cognitive performance of the group began to deteriorate markedly. By the end of 7 h of exposure to heat, increases in percent group error on investigator-paced tasks ranged from 17%-23% over control conditions. Virtually all of the decrements were due to increases in errors of omission. The productivity of the group on a self-paced task (map plotting) diminished by approximately 40% from control conditions after 6 h in the heat in protective clothing; accuracy of plotting was not markedly affected.