Arm/Hand Cooling in the Cold Exposure Survival Model
Abstract
The previously developed Cold Exposure Survival Model (CESM) is limited to predictions of cognitive impairment and survival time (time to lethal hypothermia) under conditions of cold exposure. The present development addresses motor function impairment of the arms and hands that usually occurs before cognitive impairment and well before the onset of lethal hypothermia. Two data sources were used for this purpose, one based on a field study designed to simulate survival situations and the other based on a review of the literature. The field study involved 28 healthy males on survival training divided into five groups and exposed for 6 continuous days on different occasions during two winter seasons. Despite mean(+/- SD) air temperatures ranging from -24.4+/-3.9 to 4.4+/-2.5 deg C among groups, deep body temperature T(sub core) remained normal averaging from 37.1 to 37.5 deg C. However, finger temperature T(sub finger) was significantly correlated to T(sub air) as follows: T(sub finger)=16.7+0.28*T(sub air) (r=0.53; p<0.0001). Grip strength, knot-tying, and nut-bolt assembly performance decreased most for the coldest-exposed group, which is consistent with the low T(sub finger) measured for this group (9.4+/-3.4 deg C). Percentages of their maximum performance in these respective tasks were 87.5+/-9.0, 69.2+/-12.1, and 83.8+/-18.1%. The following significant regressions were obtained using all the subjects' data: grip strength (%) = 94.7+0.30*T(sub air) (r=0.48; p<0.0001); knot-typing (%) =93.0+0.53*T(sub air) (r=0.39; p<0.0001);and nut bolt (%)=84.1+1.33*T(sub finger) (r=0.33; p<0.0002). No decrement in cognitive performance as evaluated with tests of logical reasoning, planning, and vigilance was found in any of the groups, and is attributed to the subjects' maintenance of a normal T(sub core). These data were consistent with other studies conducted under controlled laboratory conditions and were used in a revision of CESM.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 2001
- Accession Number
- ADA398370
Entities
People
- Allan A. Keefe
- Peter Tikuisis
Organizations
- Defence Research and Development Canada