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Abstract

The purpose of this field study was to examine gender differences in the sweat response reported 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 consumed, was used to estimate sweat loss during the exercise period. Men had a significantly higher sweat rate (1.12 L.h(-1)) compared to women (0.57 L.h(-1)), 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.
723
Journal of Strength and Conditioning Research, 2006, 20(3), 723–724
2006 National Strength & Conditioning Association Research Note
G
ENDER
D
IFFERENCES IN THE
S
WEAT
R
ESPONSE
D
URING
S
PINNING
E
XERCISE
L
YNTON
T. H
AZELHURST AND
N
ICOLAAS
C
LAASSEN
Department of Physiology, University of Pretoria, Pretoria, South Africa.
A
BSTRACT
.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
1
) com-
pared to women (0.57 L·h
1
), 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.
K
EY
W
ORDS
. sweat production, gender, indoor cycling, cycle er-
gometry
I
NTRODUCTION
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-
cise.
M
ETHODS
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-
sumed (7).
Subjects
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
2
;
body mass index 25.5 kg·m
2
) and 12 women (age
33.9 years; height 1.65 m; mass 60.90 kg; body sur-
face area 1.68 m
2
; body mass index 22.23 kg·m
2
)
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).
Experimental Procedures
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.
Statistical Analyses
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
p0.05.
R
ESULTS
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-
724 H
AZELHURST AND
C
LAASSEN
T
ABLE
1. Change in mass, fluid ingested, and sweat loss of
men and women following 90 minutes of spinning.
Variables
Men
Mean (SD)
Women
Mean (SD)
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
) 1.12 (0.45) 0.57 (0.26)*
Percentage sweat loss (%) 2.16 (0.91) 1.49 (0.65)*
* Significant gender difference (p0.05).
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.
D
ISCUSSION
The 90 minutes of exercise performed resulted in a sweat
rate of 1.12 L·h
1
for men and 0.57 L·h
1
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
cm
2
·kg
1
) compared to women (279 cm
2
·kg
1
). 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
pattern (3).
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.
P
RACTICAL
A
PPLICATIONS
This study has shown that both men and women leave a
spinning studio partially dehydrated. Men lost 2.2%
and women 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.
R
EFERENCES
1. A
NDERSON
, G.S., R. W
ARD
,
AND
I.B. M
EKJAVIC
. Gender differ-
ences in physiological reactions to thermal stress. Eur. J. Appl.
Physiol. 71:95–101. 1995.
2. A
VELLINI
, B.A., E. K
AMON
,
AND
J.T. K
RAJEWSKI
. Physiological
responses of physically fit men and women to acclimation to
humid heat. J. Appl. Physiol. 49:254–261. 1980.
3. B
AR
-O
R
, O. Effects of age and gender on sweating pattern dur-
ing exercise. Int. J. Sports Med. 19:S106–S107. 1998.
4. B
ROWN
, S.L.,
AND
E.W. B
ANISTER
. Thermoregulation during
prolonged actual and laboratory-stimulated bicycling. Eur. J.
Appl. Physiol. 54:125–130. 1985.
5. B
UONO
, M.J.,
AND
N.T. S
JOHOLM
. Effect of physical training on
peripheral sweat production. J. Appl. Physiol. 65:811–814.
1988.
6. C
HEUVRONT
, S.N.,
AND
E.M. H
AYMES
. Thermoregulation and
marathon running. Sports Med. 31:743–762. 2001.
7. C
HEUVRONT
, S.N., E.M. H
AYMES
,
AND
M.N. S
AWKA
. Compari-
son of sweat loss estimates for women during prolonged high-
intensity running. Med. Sci. Sports Exerc. 34:1344–1350. 2002.
8. F
RYE
, A.J.,
AND
E. K
AMON
. Responses to dry heat of men and
women with similar aerobic capacities. J. Appl. Physiol. 50:65–
70. 1981.
9. F
RYE
, A.J.,
AND
E. K
AMON
. Sweating efficiency in acclimated
men and women exercising in humid and dry heat. J. Appl.
Physiol. 54:972–977. 1983.
10. M
ORIMOTO
, T., Z. S
LABOCHOVA
, R.K. N
AMAN
,
AND
F. S
ARGENT
.
Sex differences in physiological reactions to thermal stress. J.
Appl. Physiol. 22:526–532. 1967.
11. S
HAPIRO
, Y., K.B. P
ANDOLF
, B.A. A
VELLINI
, N.A. P
IMENTAL
,
AND
R.F. G
OLDMAN
. Physiological responses of men and women
to humid and dry heat. J. Appl. Physiol. 49:1–8. 1980.
12. W
EINMAN
, K.P., Z. S
LABOCHOVA
, E.M. B
ERNAUER
,T.M
ORI
-
MOTO
,
AND
F. S
ARGENT
. Reactions of men and women to re-
peated exposure to humid heat. J. Appl. Physiol. 22:533–538.
1967.
13. W
YNDHAM
, C.H., J.F. M
ORRISON
,
AND
C.G. W
ILLIAMS
. Heat re-
actions of male and female Caucasians. J. Appl. Physiol. 20:
357–364. 1965.
Address correspondence to Dr. Nicolaas Claassen,
nico.claassen@up.ac.za
... In contrast, Hamouti et al. (2011) found no differences in sweat sodium between aerobically trained subjects and aerobically untrained subjects if values were normalized for sweat rate. Hazelhurst and Claassen (2006) reported higher sweating rates in males than females during physical exercise with fluid intake. These studies indicated that heat acclimation and sex should to be considered if sweat markers are used for dehydration diagnosis, whereas different levels of aerobic fitness may not constitute a confounding factor. ...
... Sweat chloride, sweat osmolality, and sweat sodium were demonstrated to facilitate dehydration diagnosis after 2 h of physical exercise (Morgan et al. 2004). Some factors that might confound this diagnostic potential were already studied, for example, heat acclimation (Buono et al. 2007), aerobic capacity (Hamouti et al. 2011), and sex (Hazelhurst and Claassen 2006). Moreover, regional sweat markers could be successfully converted into whole-body sweat markers (Baker et al. 2009a(Baker et al. , 2011Patterson et al. 2000). ...
... Future studies may therefore include subjects of a wider range of ages. The sweatbased approach will likely be influenced by heat acclimation (Buono et al. 2007), sweat rate differences between females and males (Hazelhurst and Claassen 2006), and diseases that affect sweat composition. For example, cystic fibrosis which leads to excessive chloride and sodium concentrations (Tortora and Derrickson 2009, Chapter 23). ...
Thesis
Full-text available
Prolonged physical exercise is often accompanied by mild to severe dehydration. Marathon runners, as an extreme example, can lose up to 14 % of their total body water (TBW) during races in warm environments. This excess of TBW loss is considered close to life-threatening. But also moderate TBW loss can impair aerobic endurance, muscular strength, and cognitive performance. In this light, the present thesis proposes three machine learning approaches for quantitative estimation of TBW loss and two theoretical approaches for efficient, nonlinear machine learning. The former approaches support the accurate diagnosis of exercise-induced dehydration as well as recommendations on fluid intake for rehydration. The latter approaches could contribute to future wearable devices for TBW monitoring, although they are not exclusively applicable to this context. The first machine learning approach utilizes core and skin temperature to correct corrupted bioimpedance measurements, which often occur because of confounding factors during physical exercise. It therefore enables the usage of the noninvasive and portable bioimpedance technology for TBW loss estimation during physical exercise. The second machine learning approach explores the potential of sweat chloride and sweat osmolality for dehydration diagnosis. It reveals correlations between the two sweat markers and TBW loss, and it proposes quantitative TBW loss estimations based on the sweat markers. The third machine learning approach synthesizes information from seven salivary markers (amylase, chloride, cortisol, cortisone, osmolality, potassium, total proteins). It demonstrates that salivary markers provide sufficient information for quantitative TBW loss estimation, which extends previous saliva-based classifications between euhydrated and dehydration individuals. All three approaches were evaluated using measurements that were collected from ten subjects after eight consecutive, 15 min intervals of physical exercise. Among several insights, like nonlinearly increasing salivary markers during progressive dehydration, the evaluation highlighted that TBW loss estimations could be achieved with an accuracy of 0.34 l, which corresponds to about a glass of water. This accuracy was achieved using salivary markers and nonlinear machine learning. The first theoretical approach weaves the powerful kernel machinery into branch and bound (B&B) feature selection. It facilitates the recognition of complex and nonlinear data structures using the efficient B&B search method. The second theoretical approach introduces an approximation of the Gaussian radial basis function (RBF) kernel for the efficient computation of nonlinear classification decisions. It also illustrates the close relationship between the kernel approximation and the reproducing kernel Hilbert space (RKHS) that is being approximated. Both approaches were evaluated on benchmark data sets, which illustrated that they constitute valuable alternatives to state-of-the-art methods. In summary, nonlinear processing of salivary markers facilitated the most accurate TBW loss estimations, and the theoretical approaches enhanced the toolbox of efficient and nonlinear machine learning. A combination of both contributions could therefore constitute the foundation for efficient, nonlinear processing of the physiological measurements and markers, which would in turn be prerequisite to develop energy-efficient, unobtrusive wearable devices for TBW monitoring.
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Thirty male and twenty-six female Caucasians were tested at work levels of 1.0 liters O 2 consumption in 90 F wet-bulb temperature, 93 F dry-bulb temperature, and 80 ft/min air velocity for comparative heat reactions in the unacclimatized state. The females had more severe physiological and psychological reactions. Rectal temperatures of 104 F and heart rates of 180 beat/min were reached more rapidly than in the male. The females sweated less and their oxygen consumptions were lower than those of the males. Ten males and four females were then acclimatized to the same extent at the same work rate in 93 F wet-bulb temperature. At the end of the period their reactions were closely similar, although the females responded slower to the acclimatization procedure. Both groups ended with heart rates of 140 beat/min and rectal temperatures of 102 F. The females, however, continued to sweat less. In a retest at 90 F wet-bulb temperature, both groups had heart rates of 130–140 beat/min and rectal temperatures of 101 F. Females still sweated less. The results demonstrate the fact that females react more severely on exposure to severe heat and work conditions. Once acclimatized, however, the temperature and circulatory reactions of both sexes are closely similar, but the females sweat less than males. acclimatization of Caucasians to heat; Caucasians—acclimatization to heat; sex differences—heat reactions; physiological reactions to heat Submitted on September 14, 1964
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Four acclimated men and four acclimated women exercised at 30% V̇O2(max) in a hot-humid environment [dry-bulb temperature (T(db))/wet-bulb temperature (T(wb)) = 37/30°C] and a hot-dry (T(db)) = 48°C, T(wb) = 25°C) environment. Variables recorded during heat stress tests, rectal temperature (T(re)), mean skin temperature, heart rate (HR), total body sweat rate (M(sw)), chest sweat rate (chest ṁ(sw)), sweat gland activity per unit surface area (ρSGA) on the chest, and sweat gland flow (SGF) on the chest were recorded. Sweating efficiency (η(sw)) was determined as the ratio of required to observed sweating. Maximum sweat gland activity per unit surface area (ρSGA(max)) was determined with the aid of methacholine. There were no differences between sexes or environments in T(re) or HR. Both sexes had significantly lower Ṁ(sw) and chest ṁ(sw) in the humid heat compared with the dry heat. The women maintained significantly lower Ṁ(sw) and chest ṁ(sw) than the men in the humid heat, with significantly higher η(sw). There were no differences in sweating rates of efficiency between sexes in the dry heat. Among the women, ρSGA relative to ρSGA(max) (%ρSGA(max)) and η(sw) were significantly higher in the dry heat than in the humid heat, but SGF was similar in both environments. Among the men, SGF was significantly higher in the dry heat than in the humid heat, and %ρSGA(max) and η(sw) were similar in the two environments. In both environments, the men recruited a significantly lower percentage of their available sweat glands than did the women. The reduction in ρSGA in the humid heat among the women allowed the women to conserve body water through improved sweating efficiency. However, the men had a larger apparent reserve to increase sweating in more severe dry heat.
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Four men and four women with similar VO2max (56.33 +/- 4.05 and 54.08 +/- 4.27 ml.kg-1.min-1, respectively) exercised up to 3 h at 30% VO2max during heat stress tests (HST) before and after acclimation to dry heat [dry-bulb temperature (Tdb)/wet-bulb temperature (Twb) = 48/25 degrees C]. Rectal (Tre), tympanic sweat on the chest (msw), and total sweat rate (Msw) were recorded. There were no differences in the responses of the women between phases of the menstrual cycle. Tre, Tty, Tsk, and Tdb at the onset of sweating were similar in both sexes before and after acclimation. The nonacclimated men had significantly higher Msw and slower rise in Tre as compared to the nonacclimated women. Following acclimation these differences were no longer evident. Acclimation produced an increase in Msw in both sexes that was characterized by an increase in sweating sensitivity (delta msw/delta Tre). It was concluded that sex alone does not determine responses to heat stress. Consideration should also be given to the relative cardiovascular strain, state of acclimation, and the ambient conditions.
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The major objective of this study was to determine whether sex-related differences in thermoregulation exist; and if so, whether there was any method to define these differences. A major methodological problem of the study was the inability to find groups of males and females matched in all their physical characteristics, namely: body weight, skin surface area, percentage of body fat and cardiorespiratory physical fitness. This problem was partially solved by dividing each sex into two subgroups and matching the subgroups as 'small' males vs. 'big' females, or more fit females vs. less fit males. The sex-related differences concluded from this investigation are summarized in Table 4. In comfortable climatic conditions (20 C, 40% rh) men and women reacted in a physiologically similar fashion. Under wet conditions, whether mild or hot, females tolerated the heat better than males. They displayed lower deep body and skin temperatures, and therefore lower heat storage, while demonstrating lower sweat rates and subsequently less dehydration than males. In contrast, under hot-dry conditions, males seemed to be at a physiological advantage. Compared to females, they showed lower deep body and skin temperatures, lower HR, lower heat storage, and similar sweat rates. (Author)