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Does reduced heat production during mild whole body cooling override increased heat generation by pre-shivering muscle tension?

Kuklane, Kalev LU ; Smolander, Juhani LU ; Holmér, Ingvar LU and Vanggaard, Leif (2011) XIV International Conference on Environmental Ergonomics In Environmental Ergonomics XIV. p.112-115
Abstract
INTRODUCTION

Preshivering thermogenesis (developing muscle tension) may not be noticed in static situations due to reduced metabolism under mild body cooling. This paper describes the observations of metabolic and heart rate changes under mild body cooling.

METHODS

Eight men participated in the study. The subjects were dressed in shorts, socks and shoes, and were seated. The air temperature (32 °C) was after 25 minutes gradually reduced to 13°C (0.2 °C/min). Rectal, finger, central skin and air temperatures were recorded. Heart rate was measured continuously. Oxygen consumption was analysed under 5 minutes at 30th and 90th minutes.

RESULTS AND DISCUSSION

Metabolic rates were commonly decreasing... (More)
INTRODUCTION

Preshivering thermogenesis (developing muscle tension) may not be noticed in static situations due to reduced metabolism under mild body cooling. This paper describes the observations of metabolic and heart rate changes under mild body cooling.

METHODS

Eight men participated in the study. The subjects were dressed in shorts, socks and shoes, and were seated. The air temperature (32 °C) was after 25 minutes gradually reduced to 13°C (0.2 °C/min). Rectal, finger, central skin and air temperatures were recorded. Heart rate was measured continuously. Oxygen consumption was analysed under 5 minutes at 30th and 90th minutes.

RESULTS AND DISCUSSION

Metabolic rates were commonly decreasing (57((+/-)8 at 30th and 55(+/-)11 W/m2 at 90th minute) during cooling. In one subject (quickest finger cooling and increased final core temperature) the metabolic rate did not reduce. His momentary AVAs reaction indicates a more complex neural input than core cooling. In one subject onset of strong shivering raised metabolism considerably. The mean heart rate of all subjects followed the major trend in metabolic rate (80(+/-)12 at 30th and 72(+/-)12 beats/min at 90th minute).

CONCLUSION

Increased metabolic rate under mild cooling was not observed, eventually due to the absence of strong enough thermo regulatory responses such as increased muscle tension and superficial shivering. There is a need to repeat the study involving EMG in order to separate thermoregulatory effects from postural effects. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
in
Environmental Ergonomics
editor
Kounalakis, Stylianos and Koskolou, Maria
volume
XIV
pages
4 pages
publisher
National and Kapodestrian University of Athens
conference name
XIV International Conference on Environmental Ergonomics
language
English
LU publication?
yes
id
8a89764d-780a-4086-afb2-d789be2f48c1 (old id 1940023)
alternative location
http://icee2011.com/images/stories/boa.pdf
date added to LUP
2011-08-11 14:54:40
date last changed
2016-04-16 07:54:17
@misc{8a89764d-780a-4086-afb2-d789be2f48c1,
  abstract     = {INTRODUCTION<br/><br>
Preshivering thermogenesis (developing muscle tension) may not be noticed in static situations due to reduced metabolism under mild body cooling. This paper describes the observations of metabolic and heart rate changes under mild body cooling.<br/><br>
METHODS<br/><br>
Eight men participated in the study. The subjects were dressed in shorts, socks and shoes, and were seated. The air temperature (32 °C) was after 25 minutes gradually reduced to 13°C (0.2 °C/min). Rectal, finger, central skin and air temperatures were recorded. Heart rate was measured continuously. Oxygen consumption was analysed under 5 minutes at 30th and 90th minutes.<br/><br>
RESULTS AND DISCUSSION<br/><br>
Metabolic rates were commonly decreasing (57((+/-)8 at 30th and 55(+/-)11 W/m2 at 90th minute) during cooling. In one subject (quickest finger cooling and increased final core temperature) the metabolic rate did not reduce. His momentary AVAs reaction indicates a more complex neural input than core cooling. In one subject onset of strong shivering raised metabolism considerably. The mean heart rate of all subjects followed the major trend in metabolic rate (80(+/-)12 at 30th and 72(+/-)12 beats/min at 90th minute).<br/><br>
CONCLUSION<br/><br>
Increased metabolic rate under mild cooling was not observed, eventually due to the absence of strong enough thermo regulatory responses such as increased muscle tension and superficial shivering. There is a need to repeat the study involving EMG in order to separate thermoregulatory effects from postural effects.},
  author       = {Kuklane, Kalev and Smolander, Juhani and Holmér, Ingvar and Vanggaard, Leif},
  editor       = {Kounalakis, Stylianos and Koskolou, Maria},
  language     = {eng},
  pages        = {112--115},
  publisher    = {ARRAY(0x9484930)},
  series       = {Environmental Ergonomics},
  title        = {Does reduced heat production during mild whole body cooling override increased heat generation by pre-shivering muscle tension?},
  volume       = {XIV},
  year         = {2011},
}