Shivering Endurance and Fatigue During Cold Water Immersion in Humans

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Authors
  1. Tikuisis, P.
Corporate Authors
Defence R&D Canada - Toronto, Toronto ONT (CAN)
Abstract
An important component of survival time during cold exposure is shivering endurance. Nine male and three female healthy and fit subjects [mean (SD) age 28.8 (6.3) years, body mass 71.7 (13.2) kg, height 1.75 (0.10)m, body fat 22.7 (7.4)%] were immersed to the upper chest level in cold water for periods ranging from 105 to 388 min on two occasions to test a prediction of shivering endurance. The water was cooled from 20 to 8C during the first 15 min of immersion and subsequently rewarmed (<20C) to elicit a near constant submaximal shivering response. The data were divided according to moderate (M) and high (H) levels of shivering intensity. Respective mean total immersion times were 250 (75) and 199 (80) min (P=0.086) at different average shivering intensities of 61 (10) and 69 (8)% relative to maximal shivering (P<0.0001). Blood plasma glucose concentration increased during the immersion [from 3.44 (0.54) pre- to 3.94 (0.60) mmol-l1(-) post-immersion (P=0.037)] and levels were higher during M (P=0.012). When compared to a model prediction of shivering endurance, shivering activity continued well beyond the predicted endurance times in 18 out of the 24 trials. The average rates of oxigen consumption over the entire immersion period were lower (P=0.002) during M [0.93 (0.20) l-min1(-)] compared to H [1.05 (0.21) l-min1(-)), and while these rates did not change during the last 90 min of immersion, there was an increase in fat oxidation. TRUNCATED
Keywords
Survival model;Survival time;Thermogenesis;Thermal stress
Report Number
DRDC-TORONTO-SL-1999-104 — Scientific Literature
Date of publication
31 Mar 2002
Number of Pages
10
Reprinted from
Eur J Appl Physiol, vol 87, 2002, p 50-58
DSTKIM No
CA021759
CANDIS No
518482
Format(s):
Hardcopy;Document Image stored on Optical Disk

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