Accession Number : ADA310104

Title :   Administration of 1-Tyrosine Prevents Cold-Induced Memory Deficits in Naval Special Warfare Personnel.

Descriptive Note : Technical rept. Jan 92-Apr 94,

Corporate Author : NAVAL MEDICAL RESEARCH INST BETHESDA MD

Personal Author(s) : Schrot, J. ; Thomas, J. R. ; Shurtleff, D.

PDF Url : ADA310104

Report Date : 01 FEB 1996

Pagination or Media Count : 31

Abstract : Thirty-six members of SEAL Team Two volunteered to serve as subjects in a field study to determine the efficacy of tyrosine to prevent cold-induced memory deficits. Members of three different platoons, over a three-year period of time, participated during annual Winter Warfare Training conducted in Alaska from January through March of each year. The subjects were first recruited, medically screened, and trained on a computerized cognitive performance assessment battery (PAB) at the Naval Amphibious Base, Little Creek, VA approximately one month prior to deploying to Alaska. Baseline test scores were obtained indoors under normothermic (70 deg F) conditions once training was completed. Once in Alaska the subjects were divided into two equivalent groups based on the test scores obtained during training. Both groups were then exposed to outdoor ambient cold temperatures, which ranged over the three years from approximately -22 deg C to -3 deg C (-1O deg F to 28 deg F), for one hour subsequent to consuming either 6.0 g of tyrosine or an equal amount of placebo. At the end of the cold exposure the subjects were brought inside and were administered the PAB. A 5 ml blood sample was obtained prior to consuming tyrosine or placebo and after completion of the test battery. The results indicate that consumption of tyrosine prevented cold-induced PAB deficits observed with the placebo group. On average the subjects who consumed placebo showed performance decrements on acquisition and memory tasks following cold exposure, while the subjects who consumed tyrosine had test scores comparable to those obtained under baseline conditions. Blood levels of tyrosine were elevated two- to three-fold in the tyrosine group compared with the placebo group 1.5 hrs after consumption; the blood levels of the two groups were comparable prior to consumption.

Descriptors :   *LOW TEMPERATURE, *MEMORY(PSYCHOLOGY), *COLD WEATHER, *UNCONVENTIONAL WARFARE, *TYROSINE, *COLD TOLERANCE, ACQUISITION, PERFORMANCE TESTS, NAVAL PERSONNEL, COGNITION, STRESS(PSYCHOLOGY), STRESS(PHYSIOLOGY), AMPHIBIOUS OPERATIONS, ALASKA, WINTER, BASE LINES, NAVAL WARFARE, CONSUMPTION, EXPOSURE(PHYSIOLOGY), MEDICAL RESEARCH, PLACEBOS, NAVAL SHORE FACILITIES, CATECHOLAMINES, OUTDOOR, BLOOD VOLUME, BLOOD SUBSTITUTES, SEAL TEAMS, SPECIAL OPERATIONS FORCES.

Subject Categories : Stress Physiology
      Psychology
      Unconventional Warfare

Distribution Statement : APPROVED FOR PUBLIC RELEASE