Citation

Castellani JW, Spitz MG, Karis AJ, Martini S, Young AJ, Margolis LM, Phillip Karl J, Murphy NE, Xu X, Montain SJ, Bohn JA, Teien HK, Stenberg PH, Gundersen Y, Pasiakos SM. Extrem. Physiol. Med. 2017; 6: e2.

Affiliation

United States Army Research Institute of Environmental Medicine, 10 General Greene Avenue, Bldg 42, Natick, MA 01760 USA.

Copyright

(Copyright © 2017, Holtzbrinck Springer Nature Publishing Group - BMC)

DOI

10.1186/s13728-017-0056-6

PMID

28878888

PMCID

PMC5586032

Abstract

BACKGROUND: Cardiovascular (CV) and thermal responses to metabolically demanding multi-day military operations in extreme cold-weather environments are not well described. Characterization of these operations will provide greater insights into possible performance capabilities and cold injury risk.

METHODS: Soldiers from two cold-weather field training exercises (FTX) were studied during 3-day (study 1, n = 18, age: 20 ± 1 year, height: 182 ± 7 cm, mass: 82 ± 9 kg) and 4-day (study 2, n = 10, age: 20 ± 1 year, height: 182 ± 6 cm, mass: 80.7 ± 8.3 kg) ski marches in the Arctic. Ambient temperature ranged from -18 to -4 °C during both studies. Total daily energy expenditure (TDEE, from doubly labeled water), heart rate (HR), deep body (Tpill), and torso (Ttorso) skin temperature (obtained in studies 1 and 2) as well as finger (Tfing), toe (Ttoe), wrist, and calf temperatures (study 2) were measured.

RESULTS: TDEE was 6821 ± 578 kcal day(-1) and 6394 ± 544 for study 1 and study 2, respectively. Mean HR ranged from 120 to 140 bpm and mean Tpill ranged between 37.5 and 38.0 °C during skiing in both studies. At rest, mean Tpill ranged from 36.0 to 36.5 °C, (lowest value recorded was 35.5 °C). Mean Tfing ranged from 32 to 35 °C during exercise and dropped to 15 °C during rest, with some Tfing values as low as 6-10 °C. Ttoe was above 30 °C during skiing but dropped to 15-20 °C during rest.

CONCLUSIONS: Daily energy expenditures were among the highest observed for a military training exercise, with moderate exercise intensity levels (~65% age-predicted maximal HR) observed. The short-term cold-weather training did not elicit high CV and Tpill strain. Tfing and Ttoe were also well maintained while skiing, but decreased to values associated with thermal discomfort at rest.

Language: en

Keywords

Deep body temperature; Finger temperature; Heart rate; IREQ; Thermal modeling