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IJOMEH 2010;23(2) 167
O R I G I N A L P A P E R S
International Journal of Occupational Medicine and Environmental Health 2010;23(2):167 – 174
DOI 10.2478/v10001-010-0020-9
CHANGES IN THE LIPID PROFILE OF BLOOD SERUM
IN WOMEN TAKING SAUNA BATHS
OF VARIOUS DURATION
WANDA PILCH1, ZBIGNIEW SZYGUŁA2, ANDRZEJ T. KLIMEK1, TOMASZ PAŁKA1, TOMASZ CISOŃ1,
PAWEŁ PILCH2, and MASAFUMI TORII3
1 University School of Physical Education, Kraków, Poland
Institute of Human Physiology
2 University School of Physical Education, Kraków, Poland
Department of Sports Medicine
3 Kyushu Institute of Technology, Kitakyushu, Japan
Graduate School of Life Science and Systems Engineering, Department of Biological Functions and Engineering,
Division of Physiological and Biochemical Adaptation
Abstract
Objectives: There is little information on lipid metabolism after sauna treatment in the literature. The present research
is aimed to determine the influence of sauna baths on fat metabolism in young women. Materials and Methods: Twenty
healthy, eumenhorreic, female volunteers (19–21 yr old) were exposed to Finnish sauna bath seven times every second day.
In group I (n = 10) each time the sauna treatment lasted 30 min, whereas in group II (n = 10) 40 min with 5-minute break
to cool down. Body mass, heart rate and blood pressure were measured before and after sauna bath. Rectal temperature
was monitored during stay in sauna room. Prior to the sauna bath and during its last two minutes the minute oxygen uptake
and the level of CO2 exhalation were analyzed in the exhaled air, and the respiratory quotient RQ was calculated. In the
blood samples collected before the sauna bath and immediately afterwards hematocrit, hemoglobin, and lipid profile —
total lipids, free fatty acids, total free fatty acids, triacylglycerols, total cholesterol (TC), high density lipids (HDL), low
density lipids (LDL) were analyzed. Results: Rectal temperature was lower in the last sauna bath than in the first one.
Losses of plasma were greater during the seventh bath than during the first one. Acceleration of the metabolism of lipids
occurs after every sauna bath. A reduced level of TC and LDLC and a raised level of HDL was observed after repeated
sauna baths. Conclusion: After 2 weeks of repeated sauna session some changes in total cholesterol and concentration of
LDLC were observed, while concentration of HDLC increased after 7th sauna bath in group I. Those kinds of changes may
be good prognoses of ischemic heart disease prevention, but further research on the influence of sauna on fat metabolism
is needed.
Key words:
Lipid profile of blood serum, Sauna
Received: January 11, 2010. Accepted: June 17, 2010.
Address reprint request to W. Pilch, Al. Jana Pawła II 78, 31-571 Kraków, Poland (e-mail: wanda.pilch@awf.krakow.pl).
INTRODUCTION
The proper concentration of individual elements of the
lipid profile of blood serum is a significant factor in pre-
venting atherosclerosis and, in consequence, the develop-
ment of myocardial ischemia. The results of the research
conducted so far show that regular physical activity has
a beneficial effect on the changes in the lipid profile, which
takes the form of a decreased level of LDL and TG con-
centration in blood serum [1,2].
Sauna baths may relieve pain in musculoskeletal disorders
and improve joint mobility in patients with rheumatic dis-
ease [3,4]. Sauna treatment has not appeared to be of risk
for patients with hypertension, coronary heart disease and
congestive heart failure when they are in stable medical
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IJOMEH 2010;23(2)168
Dishes [26]. On the basis of the results of the interview, the
nutrition of the subjects was evaluated using the computer
program Wikt 1 and the Tables of Nutritious Value of Food
Products [27]. The nutritional value of the food was calculated
taking into consideration relevant coefficients of losses con-
nected with technological processes. The mean daily energet-
ic value and the main nutrients of the food consumed by the
subjects were calculated.
The subjects were divided into two groups of ten. The first
group (Group I) took seven Finnish sauna baths every other
day, always in the morning. Each time the sauna treatment
lasted 30 min, and the subjects were in a half-lying position.
The other group (Group II) took a similar series of baths, in
an identical cycle; the only difference was that their baths last-
ed 40 minutes each, divided into 2 periods of 20 minutes, with
a 5-minute break between them. During that break the sub-
jects left the sauna room and took a cold shower (20–22°C)
for 2 minutes and then rested in a half-lying position. The
temperature in the sauna was 80.1°C on the average and the
relative humidity of the air was 5–26.6%.
All physiological and biochemical measurements were made
on the first day of the experiment (before and after the first
thermal bath) and on the fourteenth day (before and after the
last, seventh, thermal bath). On those two days the subjects
came after a night’s rest and with an empty stomach.
The following physiological indices were determined during
the research: (HR) heart rate (beats×min–1), (SBP) systolic
blood pressure (mm Hg), (DBP) diastolic blood pressure
(mm Hg), (Tre) rectal temperature (°C), (Tty) tympanic tem-
perature (°C), and (BW) body weight (kg).
The heart rate was determined using palpation and the blood
pressure was taken with a mercury sphygmomanometer. The
rectal and tympanic temperatures were monitored using elec-
tro-thermometer (Ellab, Danmark) to an accuracy of 0.1°C.
The body mass was determined by means of Sartorius elec-
tronic scales before the subjects entered the sauna and at the
end of the thermal bath. In order to determine the respiratory
indices prior to the sauna bath and during its last two minutes,
the exhaled air was collected into Douglas bags and subse-
quently analyzed using a Beckman MMC apparatus. The re-
sults were used to calculate the per-minute oxygen uptake, the
level of CO2 exhalation and the respiratory quotient RQ.
condition owing to medication [4]. Moreover, there are stud-
ies suggesting that long-term sauna bathing may help lower
blood pressure and can be an effective therapeutic modality
for patients with cardiovascular disease, especially for patients
with congestive heart failure, improving vascular endothelial
function and the left ventricular ejection fraction [3,5,6].
Nowadays sauna is an important factor in biological regen-
eration and it is used both by athletes and people who do
not practice any sport. In sport, it is very often used as one
of the training modalities [7–12]. It activates many body
systems, including the endocrine system [4,13–17]. The in-
crease in the carbohydrates utilization, being a result of
the increase in lactates concentration under thermal stress,
was observed by many researchers [13,14,18–20] and it can
be explained by increased glycolysis. The conclusion which
can be drawn from the majority of research works on the
influence of sauna on the human body conducted in Scan-
dinavian countries on volunteers using sauna on a daily
basis is that overheating causes the shifting of metabolism
toward carbohydrate changes [21–24]. The researchers,
however, did not analyze lipid metabolism and, therefore,
the present research is aimed at the comparison of physi-
ological reactions and changes in the lipid profile of blood
serum, depending on the duration of sauna baths.
METHOD
The subjects were 20 volunteers — healthy women (with
a doctor’s health certificate), non-smokers, at the age
of 19–21. They did not practice any sport and had not used
sauna before. The research project was approved of by the
Ethical Committee at the Medical Academy in Kraków.
The subjects who were qualified did not report any men-
strual irregularities and the experiment started when they
were in the first (follicular) phase of their menstrual cycle.
None of the subjects used any hormonal contraception.
Prior to the experiment, an interview was carried out dur-
ing which the subjects were asked questions regarding their
dietary habits. The condition of their nutrition was assessed
from the answers they gave to questions regarding food in-
take within 24 hours [25]. The quantity of the consumed food
was assessed using Album of Photography of Products and
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IJOMEH 2010;23(2) 169
the non-parametric Wilcoxon’s test for two independent
groups, to see whether there were statistically significant
differences between the initial anthropometric, physiologi-
cal and biochemical indices of subjects from groups I and II.
All the calculations were done using the Statgrafics package
for IBM PC.
RESULTS
The general profile of the subjects is presented in Table 1.
It shows that there was no significant difference in an-
thropometric indices between the women from groups I
and II.
The results of dietary habits assessment are presented in
Table 2. The mean daily energetic value and the main nu-
trients of the food consumed by the subjects did not dif-
fer significantly from those considered to be normal for
women of that age group [28].
Table 2. Mean daily energetic value and nutritional elements of
the subjects’ diet (n = 20) (x–±SD)
Nutrients Energetic values
Energy (kcal) 2 467.30±446.76
Proteins (g) 94.30±18.64
Fats (g) 107.36±13.82
Carbohydrates (g) 440.12±47.68
The changes in physiological parameters in both groups
of subjects during the 1st and the 7th bath are presented
in Table 3.
Blood samples of 10 cm3 were taken for biochemical analysis
from a vein on the front side of the elbow joint 10 minutes be-
fore the sauna bath and immediately afterwards. The follow-
ing biochemical parameters were determined in the venous
blood: (Hct) hematocrit, using the microhematocrit method
and (Hb) hemoglobin concentration, using the Drabkin meth-
od. The changes in the blood plasma volume were calculated
from the changes in the hematocrit values and hemoglobin
concentration according to the following formula:
% Delta PV = 100 {(Hb1/Hb2) × [100–(Hct2×0.874)]
/ [100–Hct1 × 0.874)]–1}
where Hb1 (g/dl) and Hct1 (%) are the initial values and
Hb2 and Hct2 are the final values. Hct was multiplied by 0.96
and 0.91, that is correction coefficients for the trapped plasma
and peripheral blood.
In order to determine the changes in lipid metabolism in the
blood serum, the following substances were determined: to-
tal lipids (TL), free fatty acids (FFA), total free fatty acids
(TFFA), triacylglycerols (TG), total cholesterol (TC), high
density lipids (HDL), low density lipids (LDL). The concen-
tration of lipids after sauna baths was corrected taking into
consideration the decrease in plasma volume.
STATISTICS
The obtained data were presented as mean arithmetic val-
ues ±SD. Statistical significance of the results obtained
within one group was checked using the Wilcoxon’s test
for two dependent groups. It was also checked, using
Table 1. Characteristics of participants
Parameter
Group I (30‘) Group II (45‘)
min max mean SD min max mean SD
Age (year) 19.00 21.0 19.8 0.92 19.00 20.0 19.8 0.42
BH (cm) 158.00 173.0 163.9 4.72 154.00 175.0 165.8 6.46
BM (kg) 49.36 66.6 58.4 5.81 50.88 69.1 60.0 6.67
BMI (kg/m2) 19.28 24.5 21.7 1.62 19.39 26.0 21.8 1.93
PF (%) 15.22 30.5 23.2 4.61 20.94 26.3 23.9 2.13
FM (kg) 9.20 20.2 13.6 3.59 10.87 16.8 14.3 1.88
LBM (kg) 38.91 51.3 44.8 4.32 37.51 52.5 45.7 4.97
SD — standard deviations.
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IJOMEH 2010;23(2)170
a statistically significant way as a reaction to overheating
the organism in both groups of subjects after each sauna
bath. The decrease in the plasma volume noted during the
first sauna bath was significantly higher in the subjects who
took a 30-minute baths than in the other group with lon-
ger thermal exposure and a break to cool down (group II).
During the last bath the decrease in the plasma volume was
significantly lower than during the first bath in both groups
of subjects. A single sauna bath caused a statistically signifi-
cant increase in ventilation and the level of carbon dioxide
exhalation in both groups of subjects and it was less intense
during the last bath. The changes in the respiratory quotient
(RQ) were slight in both groups of subjects and were not
statistically significant. The changes in lipid concentration
after sauna baths are presented in Table 4.
The changes in triglyceride and total cholesterol concen-
trations were slight in both groups of subjects and were
not statistically significant. After the first bath, in the
group whose exposure lasted 30 minutes there was noted
After each sauna bath, there was a statistically significant
decrease in the body mass of the subjects, which was more
evident in group II who took 40-minute baths compared
to group I, whose baths lasted 30 minutes. Before enter-
ing the sauna the rectal and tympanic temperature of the
subjects was always normal. After each sauna bath a statis-
tically significant increase in both rectal and tympanic tem-
perature was observed and it was more pronounced in the
group II who took longer baths with a break to cool down.
Besides, during the last sauna bath there was a statisti-
cally significant, lower than during the first bath, increase
in both rectal and tympanic temperature in both groups
of subjects. In both groups of subjects the heart rate also
increased significantly after the first bath. The increase in
the value of heart rate after the last bath was significantly
lower than after the first exposure to high temperature.
Systolic blood pressure increased significantly as a result
of thermal stress in both groups, both after the first and
the last thermal exposure. Diastolic pressure decreased in
Table 3. Physiological parameters after the 1st and 7th sauna
Parameters
First bath in sauna Seventh bath in sauna
before after delta before after delta
BM (kg) Group I 58.36±5.80 57.80±5.80 –0.55* 58.57±5.70 58.01±5.70 –0.56*
Group II 60.03±6.70 59.35±6.60 –0.68* 59.88±6.30 59.21±6.30 –0.67*
Tre (°C) Group I 37.30±0.30 38.40±0.30 1.10* 37.1±0.30 38.10±0.40 1.00*
Group II 37.10±0.30 38.10±0.50 1.10* 37.0±0.40 37.80±0.30 0.80*
HR
(sk.×min–1)
Group I 68.00±8.90 122.00±15.00 54.00* 66.00±10.40 106.00±15.80 40.00*
Group II 67.00±10.6 118.00±18.10 51.00* 61.00±10.50 96.00±9.70 35.00*
ΔPV (%) Group I – – –8.00* – – –9.50*
Group II – – –4.66* – – –6.14*
VE
(1×min–1)
Group I 6.46±1.52 14.31±4.30 7.85* 6.15±1.40 11.12±5.60 4.97*
Group II 6.48±2.08 10.94±3.70 4.46* 6.39±1.40 9.01±2.10** 2.60*
VO2
(1×min–1)
Group I 0.237±0.05 0.407±0.20 0.17* 0.236±0.04 0.331±0.10 0.095*
Group II 0.228±0.05 0.333±0.60 0.105* 0.23±0.06 0.295±0.02 0.065*
FE CO2
(1×min–1)
Group I 0.203±0.05 0.371±0.09 0.168* 0.203±0.49 0.295±0.11 0.092
Group II 0.192±0.49 0.30±0.070 0.108* 0.189±0.41 0.227±0.09 0.038
RQ Group I 0.82±0.07 0.92±0.10 0.10 0.85±0.09 0.87±0.10 0.02
Group II 0.85±0.05 0.89±0.10 0.04 0.83±0.07 0.76±0.06 –0.07
* p < 0.05.
** p < 0.05 — after 1st vs. 7th sauna.
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IJOMEH 2010;23(2) 171
repeated thermal treatment in sauna bath. Triglycerides
described as neutral fats are esters of glycerol and fatty
acids and the main place of their accumulation is in the
adipocytes. They are synthesized in the liver, adipose tis-
sue and intestine epithelium cells and their main role is to
store energy. Triglycerides are transported in blood mainly
as chylomicrons and lipoproteins belonging to the VLDL
group produced in the liver. The influence of overheating
on the TG level is not unequivocally determined. There
was observed both the increase in the concentration of
those lipoids in male subjects after a single overheating
of the body in the sauna [19] and the lack of such in-
crease [13].
Rovensky et al. [29] noted an increase in the amount of
triglycerides and lipoproteins of very low density (VLDL)
after 30 minutes’ overheating in water. They consider it
a very interesting phenomenon which can, however, lead
to the development or premature occurrence of athero-
sclerosis due to the fact that lipoproteins rich in triglycer-
ides have an atherogenic effect.
This hypothesis, however, was not confirmed by other
studies and in the view of the results of the present re-
search it seems to be irrelevant, at least as far as women
are concerned. The authors of the present research noted
an increase in the concentration of free fatty acids after
a statistically significant increase in FFA concentration.
After the last bath, a statistically significant increase
in HDL cholesterol was observed.
DISCUSSION
Sauna baths cause an increase in metabolic rate result-
ing from excitation of the sympathoadrenal system, hor-
monal changes and increased internal temperature of
the body [7,9,15,23]. In the accessible reference material,
there is little information regarding the trends of meta-
bolic changes in the specific conditions of the human body
overheated in the Finnish sauna. The regulation of the
speed of metabolic changes in the human body depends
mainly on the functioning of the nervous and endocrine
systems and the activity of key enzymes in the cells of pe-
ripheral tissues. The hormones influence the lipid metabo-
lism mainly by regulating the speed of key enzyme syn-
thesis and modification of the activity of those enzymes.
The research on the influence of sauna on the hormonal
balance conducted on female subjects showed an increase
in the concentration of such hormones as ACTH, cortisol,
and hGH after sauna baths [14].
The authors of the present study did not notice any chang-
es in the level of total lipids or triglycerides after single or
Table 4. Changes in lipid profile after the 1st and 7th sauna bath
Lipids
First bath in sauna Seventh bath in sauna
before after delta before after delta
TG
(mmol×l–1)
Group I 0.74±0.30 0.74±0.30 0 0.70±0.5 0.99±0.30 0.02
Group II 0.75±0.20 0.66±0.20 –0.09 0.72±0.2 0.71±0.10 –0.01
FFA
(mmol×l–1)
Group I 0.69±0.30 1.07±0.30 0.38** 0.62±0.2 0.84±0.30 0.22
Group II 0.66±0.30 0.72±0.20 0.06**** 0.66±0.4 0.85±0.40 0.19
TC
(mmol×l–1)
Group I 4.44±0.80 4.52±0.70 0.09 4.23±0.9 4.34±0.90 0.11
Group II 4.64±0.82 4.50±0.80 –0.18 4.25±0.3*** 4.12±0.70 –0.13
HDL (HDLC)
(mmol×l–1)
Group I 1.28±0.30 1.38±0.30 0.10 1.10±0.2 1.20±0.20 0.10*
Group II 1.49±0.30 1.42±0.20 –0.07 1.42±0.3**** 1.39±0.40**** –0.02
LDL (LDLC)
(mmol×l–1)
Group I 3.01±0.80 3.00±0.80 –0.01 2.93±0.9 2.96±0.80 0.03
Group II 2.85±0.80 2.78±0.80 –0.07 2.50±0.6 2.40±0.60 –0.10
* p < 0.05.
** p < 0.01 — before vs. after sauna.
*** p < 0.05 — before 1st vs. before 7th sauna.
**** p < 0.05 — Group I vs. Group II.
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