See
http://
www.Erj.Ersjournals.Com/cgi/reprint/8/12/2
088.Pdf
"facial cooling, but not nasal breathing
of cold air, induces bronchoconstriction:
a study in asthmatic and healthy subjects.
H. Koskela, h. Tukiainen.
Abstract: reflex-mediated
bronchoconstriction in cold climates may
be more important than it has previously
been thought. This issue has seldom been
studied using physiological methods. We
wanted to investigate, using physiological
methods, what triggers the
bronchoconstriction occurring at cold
ambient temperature during resting nasal
ventilation: cooling of the skin of the
face or cooling of the nasal cavity.
Three experiments were carried out in 15
stable asthmatics and 10 healthy
volunteers: 1) a whole-body exposure to
subfreezing temperature in an
environmental chamber, during which the
subjects breathed cold air through the
nose; 2) a similar exposure to subfreezing
temperature except that the subjects now
breathed warm air through the mouth from
outside the chamber; and 3) nasal
breathing of subfreezing air from a heat
exchanger whilst the subjects sat at room
temperature. Spirometric values and
facial skin temperature were measured both
during and after the exposures. Maximal
decrements (means ± standard errors) of
forced expiratory volume in one second
(fev1) in experiments 1, 2 and 3 were:
5.8±0.8, 5.1±0.7 and 2.1±0.5%,
respectively (p<0.001). Only the two
experiments in the environmental chamber
induced significant bronchoconstriction.
All responses were of similar magnitude in
the asthmatic and the healthy subjects.
The cooling of the skin of the face seems
to be the trigger for the
bronchoconstriction during resting nasal
ventilation at cold ambient temperature
both in asthmatic and nonasthmatic
subjects. Eur respir j., 1995, 8,
2088-2093." regards, richard friedel
