Date:

January 5, 2018

Source:

University of Eastern
Finland

Summary:

Scientists in Finland have shown that sauna
bathing is associated with a variety of health benefits. Using an experimental
setting this time, the research group now investigated the physiological
mechanisms through which the heat exposure of sauna may influence a person’s
health. Their latest study with 100 test subjects shows that taking a sauna
bath of 30 minutes reduces blood pressure and increases vascular compliance,
while also increasing heart rate similarly to medium-intensity exercise

Over the past couple of
years, scientists at the University of Eastern Finland have shown that sauna
bathing is associated with a variety of health benefits. Using an experimental
setting this time, the research group now investigated the physiological
mechanisms through which the heat exposure of sauna may influence a person’s
health. Their latest study with 100 test subjects shows that taking a sauna
bath of 30 minutes reduces blood pressure and increases vascular compliance,
while also increasing heart rate similarly to medium-intensity exercise.

Previously, the research
group has published findings from a population-based study indicating that
regular sauna bathing is associated with a reduced risk of coronary diseases
and sudden cardiac death, hypertension and Alzheimer’s disease and dementia. Frequent
sauna bathing has also been associated with a reduced risk of respiratory
diseases and lower CRP levels.

The experimental study
carried out in the Sauna and Cardiovascular Health project provides new insight
into changes that take place in the human body during and after having a sauna.
The study analysed the effects of a 30-minute sauna bath in 100 test subjects.
In particular, the objective was to analyse the role of vascular compliance and
reduced blood pressure in the health benefits caused by sauna bathing.

Vascular compliance was
measured from the carotid and femoral artery before sauna, immediately after
sauna, and after 30 minutes of recovery. These vascular compliance measurements
carried out in the experimental study constitute a new assessment method in a
sauna setting.

Immediately after 30
minutes of sauna bathing, test subjects’ mean systolic blood pressure reduced
from 137 mmHg to 130 mmHg, and their diastolic blood pressure from 82 mmHg to
75 mmHg. Furthermore, their systolic blood pressure remained lower even after 30
minutes of sauna bathing. Test subjects’ mean carotid-femoral pulse wave
velocity, which is an indicator of vascular compliance, was 9.8 m/s before
sauna, decreasing to 8.6 m/s immediately after. During sauna bathing, test
subjects’ heart rate increased similarly to medium-intensity exercise, and
their body temperature rose by approximately 2°C. The findings shed light on
the physiological mechanisms through which health benefits, which have been
observed at the population level and are caused by the heat exposure of sauna,
may develop.

The findings on the
effects of sauna bathing on the human body were published in the Journal of
Human Hypertension, and the findings relating to the carotid-femoral pulse
wave velocity measurements were published in the European Journal of Preventive
Cardiology. The study was funded by the Finnish Funding Agency for Innovation,
Tekes, and it was carried out by Professor Jari Laukkanen’s research group at
the University of Eastern Finland. The project partners were Harvia Ltd., Velha
Ltd., Pihlajalinna, Fintravel Ltd. and the Finnish Sauna Culture Association.
The test subjects were 100 clients of the Pihlajalinna health care service
provider. Their background information was collected by extensive surveys and
interviews, and their physical health was measured by a clinical exercise test.
The study was carried out in experimental saunas provided by the sauna stove
and sauna heater manufacturer Harvia Ltd. The experimental sauna setting was a
careful simulation of the way people in Finland take a sauna in their own
homes.

Research indicates that
regular physical exercise and a healthy lifestyle promote cardiac health and prevent
disease, but not all of the risk and protective factors are yet known. The
benefits of regular sauna bathing on cardiac health observed in the
population-based study can, according to this experimental study, be explained
by the fact that sauna bathing reduces blood pressure and increases vascular
compliance. However, further research data from experimental settings relating
to the physiological mechanisms of sauna bathing that promote cardiac health is
still needed.

Materials provided by University of Eastern Finland.
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