Journal of Applied Physiology, Vol 58, Issue 3 928-935, Copyright © 1985 by American Physiological Society
Evaluation of vapor permeation through garments during exercise
R. R. Gonzalez and K. Cena
Five males [age 28 +/- 8 yr; maximum O2 uptake (VO2max) 50 +/- 6 ml O2 .
kg-1 . min-1; body wt 70 +/- 3 kg; DuBois surface area 1.85 +/- 0.02 m2]
exercised on a cycle ergometer, placed on a Potter scale, at 31% VO2max for
up to 2 h at an ambient temperature (Ta) of 25 degrees C and a dew-point
temperature of 15 degrees C. Air movement was varied from still air to 0.4
and 2 m/s. Each subject, in separate runs, wore a track suit (TS ensemble)
of 60% polyester-40% cotton (effective clo = 0.5); a Gortex parka (GOR
ensemble), covering a sweat shirt and bottom of TS (effective clo = 1.4);
or the TS ensemble covered by polyethylene overgarment (POG ensemble).
Esophageal, skin temperature (Tsk) at eight sites, and heart rate were
continuously recorded. Dew-point sensors recorded temperatures under the
garments at ambient and chest (windward site) and midscapular sites. Local
skin wettedness (loc w) and ratio of evaporative heat loss (Esk) to maximum
evaporative capacity were determined. An observed average effective
permeation (Pe, W . m-2 . Torr-1) was calculated as Esk/loc w (Ps,sk - Pw),
where w is the average of chest and back loc w and (Ps,sk - Pw) is the
gradient of skin saturation vapor pressure at Tsk and Ta. Additionally, the
local effective evaporative coefficient was determined for chest and back
sites by Esk/(Ps,dpl - Pw). The GOR ensemble produced an almost as high a
Pe as the TS ensemble (82-86% of Pe with TS in still air and 0.4- and 2-m/s
conditions). Direct dew-point recording offers an easy practical dimension
to the study of efficacy of latent heat loss and skin wettedness properties
through garments.
