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Vi INTERNA11ONAL
SAUNA CONGRESS
HELSIKI
15—128.1974
1
1
SAUNA STUDIES
Papers read at the VI International Sauna Congress in Helsinki
on August 15—17, 1974.
EDITORS
Harald Teir
Yrjö Collan
Pirkko Valtakari
ISBN 951—95328—0—3
Vammala 1976. Vammalan Kirjapaino Oy.
HELSINKI 1976
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135
—
AIR FLOW
THE IONS IN SAUNA AIR
Gunnar Graeffe, Heimo Ihalainen, Matti Lehtimäki, Kalervo Miettinen,
Hannu Salmi
AIR
lntroduction
It has been well known for a long time that air contains both posi
tive and negative ions. The influence of the ions in the air has been
studied in many investigations (1, 2, 3). It has been shown that the
ions are capable of inducing measurable and reproducible physiological
ehanges in a variety of living forms. Investigations of the ions in the
air started at Tampere University of Technology at the end of 1973.
The aim of this work was to study the ions in sauna air in connection
with the investigations of ions in the air in different working and
living spaces.
Measuring conditions in the sauna are quite diffieult and therefore
these experiments provided a ehallenging opportunity of testing our
system. There has been some diseussion (4) about the ion distribution
in sauna air, but no measurements have been published so far.
THE BLOCK DIA6RAM OF THE
SYSTEM USED IN THE ION
MEA5UREMENTS
Fig. 1. The bloek diagram ot the system used in the ion measurements.
Experimental
Fig. 1. is the block diagram of the system whieh was used in ion
measurements. The detectors were construeted at Tampere University
of Technology. They were similar in prineiple to deteetors which
have been used widely elsewhere (5, 6). The deteetor consists of a
cylindrical capaeitor and an eleetric field persists between the elee
trodes. When air containing ions flows through the capaeitor, the
eleetrie field affects the path of an ion.
Depending on the air flow and the electric field, ions are either
Professor Gunnar Graeffe, Tampere University of Teehnology, Department of
Physies, P.O.Box 527, SF-33101 Tampere 10, Finland.
Fig. 2. the
Theresistanees
effect of an
stove
(kiuas)
on the
current
the sauna.
When
of eleetric
the stove
were
glowing
theion
density
of in
positive
ions
was mueh higher than the density 0! negative ions.
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—
136
—
captured or they pass through the capacitor. In this connection we
define the criticai mobility kg which can be obtained from the dimen
sions of the apparatus and the test conditions. For a cyiindricai capa
citor of radii R and r and lenght L we obtain the expression
(1)
in R!r
kgM
—
137
—
Fig. 3. When water (löyly) was
thrown on the stones in the electric
stove the increase of both negative
and positive ions was large. However
in the tested sauna the increase of
positive ions was much larger than
the increase of negative ions.
,(7)
2n L U
where M is the quantity of air sucked through the capacitor in cm8!
sec. and U is the voltage between the electrodes. Ali ions with mobi
lity
(2)
k= ~≥kg
E
cases in the sauna, when water
was thrown on the stove, the
number of small ions observed
was as high as 6,000!cm8.
Electric sauna
wiii be observed, whereas of the ions with mobiiities k < kg oniy the
fraction k!kg is captured. In expression (2) v is the drift veiocity of
the jon and E is eiectric fieid.
In our measurements the air flow was 1.4 litres per sec. and the
voitage ± 30 V. The criticai mobiiity in our measurement was
cm2
0.45
Vs
.
The jon current was measured with commercial eiectro
A large increase in positive
ions was observed when the
electric stove was on and the
resistances were glowing. Posi
tive ions are produced when air
flows through the stove. This
meters. We had two simiiar detectors in paraliel S0 that we couid mea
sure simuitaneousiy both negative and positive ions. The experimentai
conditions were kept the same for both detectors except that the vol
tages were opposite. The current of positive and negative ions as weli
as the temperature of the air were recorded with a 3-channel recorder.
Measurements
Two different electric saunas, one continuous-heating and one
smoke sauna, were studied. Both were located quite close to one
another and were in regular use. Both saunas were typical and com
monly used in Finland. In our measurements the criticai mobility
was 0.45
cm2
—,
so that we observed basically small ions. The amount
Vs
of such ions in normal air varied from 30Q-=---500 per cm3. In some
Fig. 4. The situtation in a continuous-heating sauna when water was thrown
on the stove.
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—
138
SM0KE—SAUNA
0
L~
139
—
0
z
—
SM0KE-SAUNA
1—
z
4W
4W
0
0
[°c]
0
T
z
[001
0
90
-3
~1
0
0
T
z
90
85
-z
TEMPERATURE
~
—~
~
80
ELE:
- — —
ZPEMPERATURE•
~-
c~
w
1—
4
~IVEi0NS~
1
“
/
85
80
— — —
--J
75
NEGATIVE 10N5
1
1
~wJ
— --____
P0SITLVE
1
2
3
4
TIME[min]
Fig. 5. In the smoke sauna the number of small negative ions increased
markedly when small amounts of water were thrown on the stove.
~
1
2
3
~
TIME[min]
Fig. 6. When a larger amount of water was thrown on the stove in the
smoke sauna a clear inerease in positive ions also was observed, but the
number of negative ions increased much more.
phenomenon could be easily tested in the laboratory. The jon distri
bution of a glowing wire has been measured earlier (8). When water
was thrown on the stove the number of both negative and positive
ions increased strongly. The number of positive ions, however,
increased more sharply.
Continuous-heating sauna
No big ehanges in the numbers of positive and negative ions could
be observed when the stove was heated. The stove was made of iron
and had only 10—20 kg of stones. The metal was not glowing during
the measurements. When water was thrown on the stones the density
of both positive and negative ions increased markedly. When the
stove is heated properly the inerease in negative ions is larger.
Smoke sauna
In the smoke sauna the number of negative ions per cu.cm.
increased strongly when water was thrown on the stove. Very few
positive ions were produced when small amounts of water were
thrown. When water was thrown in larger amounts, also the number
of positive ions inereased but not as much as the number of negative
ions.
Conclusion
The ion distribution of sauna air depends on the stove (kiuas), how
it is heated, how it is bujit and what kind of materiais are used. The
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140
SAUNA AND SPORTS
—
kiuas is the heart of the sauna (9). The glowing metal produees a
surpius of positive ions. In the smoke sauna, where the kiuas is made
of stones and usually only very few metal parts are used, the number
of negative ions is mueh greater than the number of positive ions. It
seems to us that the jon distribution of air depends on the tempera
ture of the stones in the kiuas. Further investigations are required in
which the jon distribution is followed and the temperature of the
stones is recorded at the same time. These studies are in progress.
USE OF THE SAUNA BY FINNISH ATHLETES
Ilkka Vuori
Introduction
REFERENCES
1. Kriiger A., Are negative ions good for you? New Seientist, 1973: 14 June:
668.
2. Gualtierotti, R., Bioelimatology, biometeorology, and aeroionotherapy. Ed.
by Ii. Gualtierotti, 1. H. Kornbleueh, C. Sirtori. Milan, Carlo Erba Foun
dation, 1968.
3. Kotaka 5., Krueger A. P., Studies oa the air-ion-indueed growth increase
in higher plants. Advaneing frontiers of plant seiences 1967: 20: 115.
4. Patoharju Ora, Kiukaan neljäs ulottuvaisuus? Sauna-lehti (Helsinki) 1973:
n:o 4.
5. Jonassen N., Atmosfäärinen sähkö ja huoneilmasto, LVI (Helsinki) 1967:
n:o 5.
6. Knoll M., Eichmeier J., Schön R., Properties measurement and bioelimatic
action of »small» multimoleeular atmospheric ions. Advances in electronics
and eleetron physics 1964: 19: 177.
7. Israel H., Atmospheric Electrieity, Volume 1, Jerusalem 1971, p. 218.
8. Eichmeier J., tiber Beweglichkeits- und Konzentrationsmessungen atmos
phärisher Ionen, Mtinchen 1967.
9. Patoharju Ora, Kiuas — the Heart of the Finnish Sauna, VI International
Sauna Congress, Helsinki 1974.
Sauna bathing is claimed to be an important positive faetor eon
tributing to the effectiveness of the training and eompetition of
sportsmen. Some of the indications for use of the sauna are given in
Table 1. The actual use of the sauna by sportsmen, the reasons for its
use and the perceived effects of its use have not, however, been suf
fieiently studied. Because of the long tradition and widespread popu
larity of sauna baths in Finland (Vuori at this eongress; see also Table
5), Finnish athletes ean be considered as experts in knowing the value
and indications of the sauna in sports.
Material and methods
For the reasons mentioned above, a questionnaire containing 32
questions or series of questions was mailed to 541 Finnish top athletes
in June 1974. Altogether 382 questionnaires, 70 per eent, were
returned. The results of the study are based on the analysis of 369
fully completed questionnaires representing 18 sports diseipiines
(Table 2). These were grouped into seven eategories (Table 3). The
somewhat low response rate, most likely due to the holiday season, is
not considered to reduce signifieantly the representativeness of the
material. This is indieated e.g. by the self-evaluation of the athletes
of the frequency with which they use sauna baths compared with
their fellow athletes: about 3/4 considered the frequencies equal and
about 1/5 eonsidered that they took a sauna less often than their fellow
athletes.
Ilkka Vuori, M.D., Sports Medical Research Unit, University of Turku, Kii
nanmyllynkatu 10, SF-20520 Turku 52, Finland.