The Effect of Hypoxia and Cold at Rest on Human Thermoregulation.
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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 30, 1996
- Accession Number
- ADA314896
Entities
People
- David Roberts
- J. Hodgdon
- J. Reading
- R. Pozos
Organizations
- Naval Health Research Center