Human temperature regulation during sub-anesthetic levels of
nitrous oxide-induced narcosis.
Cheung, Stephen S., and Igor B. Mekjavic.
School of Kinesiology, Simon Fraser University, Burnaby, British
Columbia, Canada V5A 1S6
APStracts 2:0035A, 1995.
The present study investigated whether nitrous oxide (N2O) attenuates
shivering thermogenesis during cold water immersion in a dose
-dependent manner. Seven male subjects were immersed to the neck for
60 min. in 20 C water on five separate occasions, while breathing
either air (AIR) or a normoxic mixture of 10, 15, 20, or 25% N2O
balanced with N2. All N2O concentrations investigated caused a
significant (p<0.02) reduction in shivering thermogenesis compared to
AIR. Despite similar heat flux from the skin (Q), the relative
changes in esophageal temperature from resting pre-immersion levels
(_Tes) were significantly (p<0.05) greater during the N2O trials
compared to the AIR trial, with no significant difference among the
N2O conditions. A dose-dependent trend in the perception of thermal
comfort was observed for the N2O conditions. It is concluded that
shivering thermogenesis, and thus thermal balance, is affected to the
same degree for the range of inspired N2O concentrations
investigated, with no discernable dose-dependent effect.
Received 22 February 1994; accepted in final form 31 January
1995.
APS Manuscript Number A184-4.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 February 1995.