2007, Piran, Slovenia

Environmental Ergonomics XII
Igor B. Mekjavic, Stelios N. Kounalakis & Nigel A.S. Taylor (Eds.), © BIOMED, Ljubljana 2007
Acetylcholine iontophoresis test. The TF (50 ±2
ml/kg/min) and TM (57 ±2 ml/kg/min) subjects had
significantly higher VO2max than the UF (41 ±1
ml/kg/min) and UM (39 ±2 ml/kg/min). The TF group
had a significantly lower VO2max than the TM group,
whereas there were no sex differences in VO2max for
the UF versus UM groups. The Tor was significantly
lower in TF (36.5 ± 0.1°C) than TM (36.7 ± 0.1°C),
UF (36.7 ± 0.1°C), and UM (36.7 ± 0.1°C) Although
no physical training effects were observed for the Tsl
on the forearm and thigh in women or men, the TF and
UF groups exhibited a lower Tsl value than the TM and
UM groups, respectively. Nevertheless, the sex
differences (0.4–0.7°C) were not large.
The Ach-induced SR on the forearm and thigh was
significantly greater in the TF and TM than in UF and
UM groups, and was lower in the TF and UF groups
than in TM and UM (Figure 2). No group differences
were observed in the Ach-induced ASG value on the
forearm and thigh. The sex- and physical trainingrelated
differences in the Ach-induced SGO
completely matched the differences for the Achinduced
SR. The effects of physical training on the
Ach-induced SR and SGO were no more marked in
women than in the men, as were the exercise-induced
SR and SGO responses.
DISCUSSION
The main findings of this study were as follows. First,
physical training enhanced the exercise- and Achinduced
SR in both sexes. Second, the degree of
enhancement of the SR with physical training was
smaller in women than in men. Finally, the enhanced
SR with physical training and the sex difference in the
effects of physical training on the SR were mainly
attributable to lower SGO and not to changes in the
number of ASG.
Sato and Sato (6) reported that the sweat glands of
subjects judged to be poor sweaters were smaller,
showing lower secretion activity and decreased
cholinergic sensitivity compared with glands from
physically fit subjects. Based on this result, it has been suggested that physical training
improves the size or cholinergic sensitivity of sweat glands in women and men, and there are
sex differences in the improvement in the size or cholinergic sensitivity of sweat glands. This
suggestion was supported by the results of the Ach-induced SR and SGO in this study.
Kawahata (4) reported that testosterone enhanced the sweating response and that estradiol
inhibited it. Moreover, Araki et al. (7) indicated that the exercise-induced SR increased
278
SR (mg/cm 2 /min)
ASG (glands/cm 2 )
SGO (µg/gland/min)
1.0
0.8
0.6
0.4
0.2
0.0
150
120
90
60
30
0
10
8
6
4
2
0
*,†
*,†
†
†
*
*
*,†
*,†
TF
UF
TM
UM
Figure 2. Sweating rate (SR),
active sweat glands (ASG), and
sweat gland output (SGO) on the
forearm and thigh during the
acetylcholine iontophoresis test
in physically trained (TF) and
untrained (UF) females and
trained (TM) and untrained (UM)
males. Values are means ± SEM.
* p < 0.05 physical trainingrelated
difference in women or
men, † Forearm Thigh
p < 0.05 sex difference in
the trained or untrained group.
†
†
*
*