Regular visits to the sauna may cut a person's risk of death dramatically, according to a study conducted by researchers from the University of Eastern Finland at Kuopio and published in the journal JAMA Internal Medicine.
Middle-aged men who visited the sauna most frequently were 40 percent less likely to die from all causes during a 10-year period than men who went least often. Spending longer in the sauna on each visit also decreased the risk of death, with the greatest benefit coming from visits of 20 minutes or more.
Hot, dry saunas
The study was conducted in eastern Finland, which has a longstanding tradition of sauna use. The traditional Finish sauna is hot - 80 to 100 degrees Celsius - but dry, with only 10 to 20 percent humidity.
The research was conducted on 2,315 men between the ages of 42 and 60. The mean age was 53 and the average BMI was 26.9. At the start of the study, participants filled out questionnaires to help researchers assess cardiovascular risk factors such as activity level, alcohol consumption, blood pressure, smoking and socioeconomic status. Participants also reported on medication use and on any chronic diseases, which were confirmed by a doctor. The researchers directly measured participants' blood pressure, body mass index, and cholesterol, and also took measures of their heart and lung fitness.
The researchers then looked at how many men died, in 10 years of follow-up, from cardiovascular disease, coronary heart disease, sudden cardiac arrest, and all causes. Deaths were confirmed with medical records.
Deaths from other causes were not analyzed separately, including some causes with a cardiovascular component such as cancer, burst aortic aneurysm, cardiac tamponade or pulmonary embolism. Men who died within five years of the study's start were also excluded.
Reason for benefit still unknown
The researchers found that compared with those who went to the sauna only once a week or less, those who went two to three times per week were 24 percent less likely to die from all causes, 22 percent less likely from sudden cardiac death, 23 percent less likely from coronary heart disease and 27 percent less likely from cardiovascular disease.
The risk reductions among those who made four to seven visits per week were dramatically higher: 40 percent (all causes), 66 percent (sudden cardiac death), 48 percent (coronary heart disease) and 50 percent (cardiovascular disease).
Length of sauna visit also had a striking impact. Compared with those with an average visit shorter than 11 minutes, those whose visits were 11 to 19 minutes long were 7 percent less likely to die from sudden cardiac death. Spending more than 19 minutes per visit reduced sudden cardiac death risk by a whopping 52 percent. Similar benefits were seen for death from cardiovascular disease and coronary heart disease.
Length of sauna visit had no impact on all cause mortality.
All effects remained after controlling for other risk factors. The effect seemed strongest, however, among nonsmokers, people with type 2 diabetes and those with poor cardiorespiratory fitness.
"Although we do not know why the men who took saunas more frequently had greater longevity (whether it is the time spent in the hot room, the relaxation time, the leisure of a life that allows for more relaxation time, or the camaraderie of the sauna), clearly time spent in the sauna is time well spent," said journal editor in chief Rita Redberg, of the University of California-San Francisco, in an accompanying editorial.
"Often I have advised a patient who was considering an unnecessary test, such as a coronary artery calcium test or carotid ultrasonography from a mobile van, to forgo that test and instead spend the money on something that he or she would actually enjoy, such as a massage or spa treatment."