Sauna and respiratory disease: what one long study found
A 25-year Finnish study linked frequent sauna use with fewer diagnoses of COPD, asthma and pneumonia. Here’s what that comparison can, and can’t, tell us.
The short version
Researchers followed 1,935 middle-aged men in eastern Finland for a median of 25.6 years and recorded 379 diagnoses of chronic obstructive pulmonary disease, asthma or pneumonia. Men who used the sauna two to three times a week had a lower rate of these diagnoses than men who went once a week or less, and men who went four or more times a week had a lower rate still. The men chose their own sauna habits, and the study cannot show that sauna prevents respiratory disease, only that the two were linked in this group.
Keep in mind
An association, not proof of cause and effect. Only men took part, from one region of Finland, and sauna habits were recorded once, at the start.
What they found
During follow-up, 379 of the men were diagnosed with a respiratory disease. Compared with men who used the sauna once a week or less, those who went two to three times a week had a hazard ratio of 0.73 (95% confidence interval 0.58 to 0.92), and those who went four or more times a week had a hazard ratio of 0.59 (0.37 to 0.94).
For pneumonia specifically, the hazard ratios were 0.72 (0.57–0.90) for two to three sessions a week and 0.63 (0.39–1.00) for four or more. The upper end of that second estimate touches 1, a reminder of the uncertainty.
In plain terms, diagnoses of these respiratory conditions were less common among more frequent sauna users in this cohort. That is a comparison between groups, not a personal risk estimate.
What this means for your practice
This is an interesting association if you already enjoy the sauna, not a way to prevent COPD, asthma or pneumonia. Respiratory diseases have many causes, and this study does not change how any of them should be diagnosed or treated.
This does not establish a sauna routine to follow, or show that a KUUME ritual affects respiratory health.
Methods and limitations
What the researchers did
The researchers followed 1,935 middle-aged men in eastern Finland for a median of 25.6 years, and recorded diagnoses of chronic obstructive pulmonary disease, asthma or pneumonia from hospital records. The men are part of the same Kuopio Ischaemic Heart Disease (KIHD) study as our heart-health and dementia articles.
At the start of the study, the men reported how often they used a sauna: once a week or less, two to three times, or four or more times. The researchers compared diagnosis rates between these groups.
The analysis adjusted for other known risk factors for respiratory disease. As with the other KIHD analyses, nobody was asked to change their habits.
How much can this tell us?
The study has real strengths: a large group, a very long follow-up, and diagnoses taken from hospital records rather than self-report.
But it is observational, from the same cohort as our other KIHD articles. Men who used the sauna often may have differed in other ways, such as smoking, fitness or general health, that the statistics could not fully capture. Only men took part, and sauna habits were recorded once, at the start.
The researchers did not test how sauna might affect the airways; this study compared habits with later diagnoses, nothing more.
What makes it useful
- 1,935 men followed for a median of 25.6 years
- Diagnoses taken from hospital records, not self-report
- Adjusted for other known respiratory risk factors
What limits it
- Observational: an association, not proof of prevention
- Only men, from one region of Finland
- The same cohort as our heart-health and dementia articles
- Sauna habits recorded once, at the start
Where this study fits
Where this study fits
We score claims, not single studies. This one is part of the evidence for:
Regular sauna means fewer respiratory diseases, like pneumonia. Some support
Low certaintyMedium effectIllness and death
Respiratory disease 41% fewer
Likely 6% to 63%
Pneumonia 37% fewer
Likely 0% to 61%
Fewer cases than the comparison group. The bar is the best estimate, the band behind it the likely range.
From the same participant group as 7 other articles in The Study, so we count them as one group of people.
Read the original
Kunutsor SK, Laukkanen T, Laukkanen JA. Sauna bathing reduces the risk of respiratory diseases: a long-term prospective cohort study. Eur J Epidemiol. 2017;32(12):1107-1111.
DOI 10.1007/s10654-017-0311-6 · PubMed 28905164