Accession Number : ADA323293

Title :   The Effect of Hypoxia, Cold, and Exercise on Human Thermoregulation.

Descriptive Note : Interim rept.,

Corporate Author : NAVAL HEALTH RESEARCH CENTER SAN DIEGO CA

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

PDF Url : ADA323293

Report Date : 23 DEC 1996

Pagination or Media Count : 20

Abstract : U.S. Marine and Navy personnel may be at an increased risk for developing hypothermia when training at 2700 m. The objective of this study was to determine if exposure to moderate cold and decreased oxygen (O2) tension (15% O2 simulating 2700 m) reduces the ability of the human body to shiver and to maintain core and skin temperatures during moderate exercise. Eight male and two female U.S. Navy and Marine Corps personnel participated as subjects. Subjects were exposed to 4.4 deg C air breathing either 20.9% O2 (N) or 15% O2 (H) for 120 min, 40 min sitting, then 40 min walking on a treadmill at 3.0 mph, then sitting for 40 min. All subjects shivered vigorously during N and H cold as observed by investigators, reported in thermal sensation, and measured by electromyograms. The exposure of H does not decrease the ability of the human body to shiver. The respiratory exchange ratio did increase with H, indicating an increased need for glucose, and H decreased the O2 blood saturation, indicating less O2 is being carried in the blood, resulting in a possible limitation in maximal aerobic capacity. Therefore, thermoregulation during military missions conducted at altitudes up to 2700 m should not be affected adversely by the reduction in inspired O2.

Descriptors :   *HYPOXIA, *TEMPERATURE CONTROL, *AEROBIC PROCESSES, *EXERCISE(PHYSIOLOGY), THERMAL PROPERTIES, MILITARY OPERATIONS, RISK, NAVAL PERSONNEL, OXYGEN, MISSIONS, RESPIRATORY SYSTEM, HUMAN BODY, MARINE CORPS PERSONNEL, HEAT BALANCE, HYPOTHERMIA, SENSES(PHYSIOLOGY), GLUCOSE, GAS EXCHANGE(BIOLOGY), BODY TEMPERATURE, ELECTROMYOGRAPHY.

Subject Categories : Biology
      Stress Physiology
      Thermodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE