In Finland, sauna bathing has been practiced for centuries, either for pleasure, but more importantly also for reasons of hygiene and maintenance of health. Many curative and magical eﬀects have been attributed to its practice and seldom has it been thought to cause any disease.
The benefit of the sauna lies in its increased temperatures. Heat therapy has many beneﬁts for human physiology. The heat stimulates the sensory receptors in the skin, decreasing transmission of pain signals to the brain to relieve discomfort, and increases the ﬂow of oxygen and nutrients to the muscles, helping to heal damaged tissue through thermoregulatory mechanisms. Previous studies have also shown an association between controlled heat stress and augmented cardiovascular function. In line with these ﬁndings, it has also been suggested that heat therapy may improve microvascular function.
There are diﬀerent ways to apply heat therapy, such as using dry heat or warm water immersion in hot tubs. However, the use of dry heat via hot sauna exposure has been gaining popularity, especially after it has been shown to alleviate acute and chronic conditions such as asthma, headaches, incidence of colds and other related broncho-constructive disorders.
Now, there may be evidence to support one more benefit of going to the sauna: a decrease in the risk of elevated blood pressure. Some previous studies have suggested that blood pressure levels are lower among people who are living in warm climate and changes in ambient temperature can be seen parallel in blood pressure levels. Recent research also suggests that the risk of developing elevated blood pressure was nearly 50% lower among men who underwent a sauna four to seven times a week compared to men who had a sauna bath only once a week.
The Kuopio Ischaemic Heart Disease Risk Factor Study included 1,621 middle-aged men living in Eastern Finland. In the study, the men were divided into three groups based on their sauna-bathing habits: those taking a sauna once a week, those who went two to three times a week, and those who went four to seven times a week. After the exclusion of people already with hypertension at the beginning of the study, during an average follow-up of 22 years, 15.5% of the men developed clinically defined hypertension. The risk of hypertension decreased 24% among men who frequented the sauna two to three times a week, and lowered 46% among men who had sauna baths four to seven times a week.
As high blood pressure is one of the most important risk factors of cardiovascular disease, this study suggests that a reduced risk of hypertension could be a possible mechanism mediating the beneficial effect of sauna on the cardiovascular system.
“The heat stimulates the sensory receptors in the skin, decreasing transmission of pain signals to the brain to relieve discomfort, and increases the ﬂow of oxygen and nutrients to the muscles, helping to heal damaged tissue through thermoregulatory mechanisms.”
It was found that sauna bathing may decrease systemic blood pressure through a number of biological mechanisms. In the sauna, the body temperature may rise up to 2°C, causing vasodilation. Regular sauna bathing also improves the function of the inside layer of blood vessels – also known as endothelial function – which has beneficial effects on systemic blood pressure. Sweating, in turn, removes fluid from the body and also contributes to decreased blood pressure levels. Additionally, the overall relaxation of the body and mind when undergoing sauna bathing may also work to lower systemic blood pressure.
To prevent hypertension, it is recommended to reduce the salinity of the diet, increase exercise and, if possible, pay attention to weight management. However, the regular practice of Finnish saunas exerts a lot of positive health eﬀects that go beyond the cardiovascular system, and it is associated not only with a reduction of cardiovascular but also with all-cause mortality. Combining sauna bathing with regular physical activity seems to be a particularly attractive mean to boost the eﬀects of these lifestyle measures.
Featured image credit: Bath by kathrina5. CC0 public domain via Pixabay.