Accession Number : ADA314896

Title :   The Effect of Hypoxia and Cold at Rest on Human Thermoregulation.

Descriptive Note : Technical rept.,

Corporate Author : NAVAL HEALTH RESEARCH CENTER SAN DIEGO CA

Personal Author(s) : Reading, J. ; Roberts, D. ; Hodgdon, J. ; Pozos, R.

PDF Url : ADA314896

Report Date : 30 JUL 1996

Pagination or Media Count : 18

Abstract : Cold is associated with altitude, and the higher the altitude, the lower the temperature. As the ambient temperature decreases, oxygen consumption (VO2) in humans at rest increases (Feith, Hesslink, Reading, Kincaid, & Pozos, 1993; LeBlanc, 1986; Reading, Kincaid, Roberts, Hesslink, & Pozos, 1994; Robinson & Haymes, 1990; Tikuisis, Bell, & Jacobs, 1991). As cold stress increases, VO2 and heat production rise. This rise is primarily due to shivering (Kleinebeckel & KIussmann, 1990). When hypoxia is added to cold at rest, less shivering and a lower VO2 can occur. Controversy exists as to the threshold altitude or oxygen (O2) percentage at which shivering is reduced. A threshold level of 12% oxygen (simulating an altitude of 4160 m) has been proposed for reduction in shivering and VO2 (Kottke, Phalen, Taylor, Visscher, & Evans, 1948; Blatteis, 1971). Resting thermogenesis, or the ability of the body to create heat in order to maintain homeostasis, occurs in part by shivering. If shivering is limited, decreased, or stopped, core temperature will decline, and the person will become hypothermic and eventually die if core temperature is not restored to normal. In a military environment, hypothermia will impede combat performance by rendering the hypothermic person ineffective to carry out his/her mission, and it will increase manpower demands by requiring attention from at least one other person. Therefore, maintenance of a stable core temperature during cold exposure is of paramount importance if troops are to be battle ready.

Descriptors :   *PERFORMANCE(HUMAN), *HYPOXIA, *OXYGEN CONSUMPTION, *BODY TEMPERATURE, STRESSES, TEMPERATURE, LOW TEMPERATURE, STABILITY, COMBAT EFFECTIVENESS, ENVIRONMENTS, CORES, HUMANS, THRESHOLD EFFECTS, OXYGEN, MANPOWER, MILITARY APPLICATIONS, EXPOSURE(PHYSIOLOGY), ALTITUDE, HEAT BALANCE, HYPOTHERMIA, REST, HOMEOSTASIS, SHIVERING.

Subject Categories : Medicine and Medical Research
      Stress Physiology

Distribution Statement : APPROVED FOR PUBLIC RELEASE