2007, Piran, Slovenia

Sweating
REGIONAL DIFFERENCES IN TORSO SWEATING
Christiano A. Machado-Moreira 1 , Foske M. Smith 1 , Anne M.J. van den Heuvel 1 , Igor. B.
Mekjavic 2 , and Nigel A.S. Taylor 1
1 Human Performance Laboratories, University of Wollongong, Wollongong, Australia and
2 Jozef Stefan Institute, Ljubljana, Slovenia.
Contact person: nigel_taylor@uow.edu.au
INTRODUCTION
The distribution of sweating across human body segments has been investigated for many
years (Weiner, 1945), and by numerous research groups. However, very few have reported
localised differences in sudomotor function within separate body segments (e.g. Taylor et al.,
2006). In this project, we focussed on the regional distribution of sweating within the torso.
Although representing about 40% of the total body surface area, and accounting for
approximately 50% of the whole-body sweat secretion (Weiner, 1945), the torso has not been
thoroughly examined with regard to its inter-site distribution of sweating during rest and
incremental exercise in the heat. Since this information forms essential background
knowledge for the development of thermal manikins, and for improving clothing design, we
set about obtaining these data, and quantified sweat secretion rates from twelve sites of the
human torso across a wide range of thermal loads.
METHODS
Ten healthy, physically-active males (26.7 SD 4.7 y; 75.5 SD 8.5 kg; 178.3 SD 6.6 cm),
rested for 50 min in a heated, climate-controlled chamber (36 o C, 60% relative humidity),
whilst wearing a whole-body, water-perfusion suit (Cool Tubesuit, Med-Eng, Ottawa,
Canada) perfused with water at 40 o C. Subjects then performed incremental cycling
(increasing from 50 W by 25-W steps every 15 min). Trials were terminated when core
temperature exceeded 39.5 o C for 2 min (N=2) or at volitional fatigue (N=8). The average
exercise duration was 66.3 min (range: 52-85 min).
Local sweat rates were measured using ventilated sweat capsules (3.16 cm 2 ; Clinical
Engineering Solutions, NSW, Australia) positioned at twelve sites on the left torso: upper and
lower chest; upper and lower abdomen; upper back 1 (highest) and 2; lower back 1 and 2
(lowest); shoulder (trapezius); and at the upper, middle and lower lateral surfaces (Figure 1).
Only six sweat rates could be recorded simultaneously, so the six remaining capsules were
ventilated with room air to sustain a dry skin surface. During rest, only six sites were
investigated, while during exercise, capsules were connected to the sweat system in a rotating
pattern. To control this pattern, two trial sequences were established, with five subjects
participating in each sequence. Subsequently, five minutes prior to each work rate increase,
sites of sweat measurement were changed so that the six remaining sites were now connected
to the sweat system. Changes were performed manually, and lasted between 2-2.5 min. This
rotation pattern was then continued until the trial terminated.
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