Journal of Strength and Conditioning Research, 2006, 20(3), 723–724
䉷2006 National Strength & Conditioning Association Research Note
IFFERENCES IN THE
Department of Physiology, University of Pretoria, Pretoria, South Africa.
.Hazelhurst, L.T., and N. Claassen. Gender differ-
ences in the sweat response during spinning exercise. J. Strength
Cond. Res. 20(3):723–724. 2006.—The purpose of this ﬁeld study
was to examine gender differences in the sweat response re-
ported in the literature in trained men and women during indoor
cycling. In the present study, 14 men and 12 women took part
in a 90-minute spinning class in preparation for a 108-km road
race. Delta body mass, corrected for the volume of water con-
sumed, was used to estimate sweat loss during the exercise pe-
riod. Men had a signiﬁcantly higher sweat rate (1.12 L·h
pared to women (0.57 L·h
), despite the fact that there were no
signiﬁcant gender differences in ad libitum ﬂuid intake. Future
research should focus on determining whether women may be
more efﬁcient in sweat production and evaporation and whether
men may have a greater reserve capacity for increased sweating.
. sweat production, gender, indoor cycling, cycle er-
Comparative studies of thermoregulatory re-
sponses in men and women have not produced
consistent results. Although gender-related dif-
ferences in thermoregulation have been attri-
buted to (a) morphological differences, (b) differing sweat-
ing responses and mechanisms, and (c) cardiac systemic
differences, some studies have reported similar thermo-
regulatory responses in both genders (1).
Spinning is an indoor group cycling exercise that com-
bines an aerobic and anaerobic workout on a modiﬁed
ergometer. Ambient conditions, particularly lack of wind
ﬂow in the indoor spinning studio, promote an increase
in water vapor as sweat is vaporized. Previous research
has shown that indoor laboratory conditions resulted in
a 36–38% increase in sweat rate compared to simulated
outdoor conditions (4).
The aim of this study was to attempt to verify and
quantify gender differences in the sweat response report-
ed in the literature during 90 minutes of spinning exer-
Experimental Approach to the Problem
The current ﬁeld study was designed to compare gender
differences in the sweat response while subjects were cy-
cling in an indoor setting. In order to address the aims of
the study, it was necessary to estimate sweat rate during
the exercise and to determine the morphology of the par-
ticipants. Men and women preparing for a 108-km cycling
event were allowed to drink water ad libitum during a
90-minute training session at a local spinning studio.
Sweat volume was estimated from the change in semi-
nude body mass corrected for the volume of ﬂuid con-
A total of 26 subjects, 14 men (age ⫽38.7 years; height
⫽1.82 m; mass ⫽83.57 kg; body surface area ⫽2.06 m
body mass index ⫽25.5 kg·m
) and 12 women (age ⫽
33.9 years; height ⫽1.65 m; mass ⫽60.90 kg; body sur-
face area ⫽1.68 m
; body mass index ⫽22.23 kg·m
took part in this study. Participants attended at least 2
spinning classes a week and trained for a minimum of 3
hours a week on a road bicycle. It was assumed that the
spinners were ﬁt and at least partially heat acclimatized,
as they were training in preparation for an upcoming na-
tional race. Subjects signed an informed consent after be-
ing given instructions on the study to be undertaken. The
study had been approved by the Ethics Committee of the
Faculty of Medicine, University of Pretoria (S 139/2001).
Testing took place in the late afternoon at a spinning stu-
dio with 9 overhead fans. Each participant subjectively
modiﬁed exercise intensity by adjusting the ﬂywheel re-
sistance on a scale of 1 to 10. Various exercise intensities
(i.e., climbing a hill, sprinting, or pacing with the bunch)
were achieved by adjusting the ﬂywheel resistance on the
spinning cycle at the command of the instructor.
Sweat loss was calculated from seminude body mass
measured on an electronic scale (Toledo, Worthington,
OH) with an accuracy of 0.02 kg. Volume of sweat pro-
duced was estimated from the change in body mass mea-
sured directly pre- and postexercise. The value was cor-
rected for the volume of ﬂuid ingested during the class,
determined by the change in mass of the water bottle pre-
and postexercise. Subjects emptied their bladders before
determining pre-exercise mass.
Two-sample t-tests were used to discern any signiﬁcant
differences between the means for gender characteristics
and sweat loss. All analyses were performed using the
Statistix (version 8.0; Analytical Software, Tallahassee,
FL) software package. Statistical signiﬁcance was set at
A signiﬁcant gender differences in mass and height re-
sulted in a signiﬁcant difference in body surface area,
body surface area to mass ratio, and body mass index.
There was, however, no signiﬁcant age difference be-
tween the genders.
Table 1 illustrates the gender differences in the sweat
response as a result of 90 minutes of spinning exercise.
There was a signiﬁcant difference in the change of mass
from pre-exercise values. The average body mass of wom-
1. Change in mass, ﬂuid ingested, and sweat loss of
men and women following 90 minutes of spinning.
⌬Body mass (kg) 0.58 (0.89) ⫺0.35 (0.63)*
Fluid ingested (L) 1.20 (0.30) 1.26 (0.62)
Sweat volume (L) 1.77 (0.71) 0.91 (0.41)*
Sweat rate (L·h
) 1.12 (0.45) 0.57 (0.26)*
Percentage sweat loss (%) 2.16 (0.91) 1.49 (0.65)*
* Signiﬁcant gender difference (p⬍0.05).
en increased from the pre-exercise mass, and the average
body mass of men decreased signiﬁcantly from pre-exer-
cise levels. This resulted in a signiﬁcant gender difference
in sweat rate. There was no signiﬁcant gender difference
in the volume of ﬂuid consumed during the class.
The 90 minutes of exercise performed resulted in a sweat
rate of 1.12 L·h
for men and 0.57 L·h
for women (Table
1). This difference occurred despite the fact that men and
women consumed similar volumes of ﬂuid ad libitum.
Similar signiﬁcant differences in sweat response of men
and women have also been reported by other investiga-
tors (2, 8, 9–13).
Anthropometrically, men and women differed signiﬁ-
cantly in terms of height and mass, resulting in a signif-
icant difference in body surface area, body surface area
to mass ratio, and body mass index. Women generally
have a smaller body mass and body surface area, com-
pared with men, but they typically have larger surface
area-to-mass ratios. In the present study, men had a sig-
niﬁcantly smaller body surface area-to-mass ratios (248
) compared to women (279 cm
). Since ex-
ercise heat production is proportional to body mass, and
since heat loss is a function of body surface area, women
would generate less heat and be able to dissipate more
than men for the same relative exercise intensity (2, 6).
In humid environments, women may reduce sweat
loss to a rate approximating the required rate of evapo-
ration through a reduction in the number of active sweat
glands, thus reducing wasted sweat (9–11). Lower sweat
response in women may also be related to suppression of
excessive sweat output, implying that women have a
more sensitive feedback from the wetted skin surface to
prevent excessive dripping of sweat (2). The higher sweat
gland density of women (5) results in smaller and closer
sweat droplets, allowing for a more economical sweating
Men, however, recruit relatively fewer sweat glands
than women, indicating that men have a greater reserve
capacity for further increasing sweating, should it be re-
quired (9–11). The larger volume of sweat produced per
gland by men (5) (i.e., drops that are larger and further
apart) could provide better evaporative cooling in envi-
ronments in which dry air temperature is close to skin
temperature and evaporative cooling is the main source
of heat loss (3).
Future research in a controlled laboratory setting
should, then, focus on determining whether women have
superior feedback mechanisms to control sweat produc-
tion and to therefore limit dehydration.
This study has shown that both men and women leave a
spinning studio partially dehydrated. Men lost 艐2.2%
and women 艐1.5 % of their initial body mass as a result
of sweat production. Men and women partaking in spin-
ning exercise must be informed that different hydration
protocols need to be followed during and after their clas-
ses because of the differences in sweat response.
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Address correspondence to Dr. Nicolaas Claassen,