This study examined whether palm cooling (PC) could reduce heat strain, measured through changes in core, mean skin, mean body temperatures, and thermal sensation in resting hyperthermic subjects wearing chemical protective garments. Ten male subjects performed three exercise bouts (6.1 km h−1, 2–4% grade) in a hot, dry environment [mean (SD) air temperature 42.2 (0.5°C), relative humidity 36.5 (1%)] until core temperature reached 38.8°C. Subjects then simulated transport in an armoured vehicle by resting in a seated position for 50 min with either no cooling (NC), (PC at 10°C) or palm cooling with vacuum application around the hand (PCVAC, 10°C, 7.47 kPa negative pressure). Core, skin, and mean body temperatures with PC and PCVAC were lower (P < 0.05) than NC from 15 to 50 min of cooling, and thermal sensation was lower (P < 0.05) from 30 to 50 min, with no differences in any variables between PC and PCVAC. Maximal heat extraction averaged 42 (12 W), and core temperature was reduced by 0.38 (0.21°C) after 50 min of PC. Heat extraction with PC was modest compared to other cooling approaches in the literature.
Armoured vehicle transport Hyperthermia Palm cooling Rapid thermal exchanger
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This study was supported by the Defense Advanced Research Projects Agency W911NF-06-1-0025. The authors thank the subjects for their perseverance and cooperation in completing this study. They also thank AVA core technologies (Ann Arbor, MI, USA) and Drs. Heller and Grahn for useful input during this study. Many thanks to CSA Engineering for providing the technology to quantify heat extraction and technical support.
Conflict of interest statement
No conflict of interest exists.
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