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sampling periods (0.80 to 2.21 pg per ml, mean values) is within the range of normal for young adult men with plasma osmolality less than 290 milliosmoles per kg.


As shown from these studies, young adult men consuming a daily diet containing only 4 g of NaCl can work consecutive days in a desert environment and achieve full acclimation to this specific heat-work scenario. The endocrinological adaptations occurring especially during the first several days of the dietary-heat-work regimen may be important to the physiological adaptations and electrolyte equilibria needed for achieving acclimation. These hormonal responses moderated during the latter portions of the experimental regimen, which indicates a dietary and acclimation steady-state characterized by greatly reduced physiological strain to the test volunteers. These results imply that healthy young individuals can acclimate quite rapidly to work in desert environments despite relatively restricted salt intake.


The authors gratefully acknowledge the technical, technological, and logistical support of many U.S. Army Research Institute of Environmental Medicine and U.S. Army Natick Research, Development, and Engineering Center personnel. A special thanks to the test volunteers who participated in this study. Without their cooperation, it could not have been executed.


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