Almost every “benefits of sauna” list traces back to the same place: a long-running study of people in and around Kuopio, in eastern Finland. Its researchers asked people how often they used a sauna, then followed them for about 15 to 26 years.
This page lays out six of its findings with the numbers, and what they can’t tell you. It is general information, not medical advice. For the wider evidence, including hospital guidance, see the overview of sauna health benefits.
Short answer: in the Kuopio study, people who used a sauna 4 to 7 times a week had lower risk of fatal heart disease, high blood pressure, stroke, dementia, and pneumonia than people who went once a week. The risk ratios ranged from 0.23 to 0.63. The study is observational and mostly of middle-aged Finnish men, so it shows a link, not that the sauna caused it.
How the study worked
The Kuopio Ischemic Heart Disease study enrolled men aged 42 to 60, with baseline exams between 1984 and 1989, according to Laukkanen (2017). The later papers also included women. At the start, each person reported how often they used a sauna. Researchers then recorded who later developed each condition, and compared groups using a hazard ratio.
A hazard ratio of 0.50 means half the risk of the comparison group over the follow-up. In every paper below, the comparison group used a sauna about once a week.
The six findings
| Outcome | Paper | People | Follow-up | 4-7 times a week vs once |
|---|---|---|---|---|
| Fatal heart disease | Laukkanen, BMC Medicine, 2018 | 1,688, 51.4% women | 15.0 years | 0.23 |
| Dementia | Laukkanen, Age and Ageing, 2017 | 2,315 men | 20.7 years | 0.34 |
| Stroke | Kunutsor, Neurology, 2018 | 1,628 men and women | 14.9 years | 0.38 |
| High blood pressure | Zaccardi, American Journal of Hypertension, 2017 | 1,621 men | 24.7 years | 0.53 |
| Respiratory disease | Kunutsor, European Journal of Epidemiology, 2017 | 1,935 men | 25.6 years | 0.59 |
| Pneumonia | Kunutsor, Respiratory Medicine, 2017 | 2,210 men | 25.6 years | 0.63 |
Figures are each paper’s most-adjusted hazard ratio in its abstract. The respiratory and pneumonia papers compared 4 or more sessions with 1 or fewer.
Heart disease, in men and women
Laukkanen (2018) followed 1,688 people aged 53 to 74 for 15 years, and 181 died of heart disease. After adjusting for risk factors, physical activity, and socioeconomic status, the ratio was 0.75 for 2 to 3 sessions a week and 0.23 for 4 to 7. The authors concluded:
“Higher frequency and duration of sauna bathing are each strongly, inversely, and independently associated with fatal CVD events in middle-aged to elderly males and females.”
Laukkanen T et al., BMC Medicine, 2018
CVD stands for cardiovascular disease.
Blood pressure
Zaccardi (2017) followed 1,621 men without high blood pressure for a median of 24.7 years, and 251 developed it. With full adjustment, the ratio was 0.53 for 4 to 7 sessions. For 2 to 3 sessions it was 0.83, which was not statistically significant.
Stroke
Kunutsor (2018) followed 1,628 men and women for 14.9 years and recorded 155 strokes. The ratio for 4 to 7 sessions was 0.38 after adjusting for physical activity and socioeconomic status. The authors found the link held across age and sex.
Dementia
Laukkanen (2017) followed 2,315 men for 20.7 years and recorded 204 cases of dementia. The ratio was 0.34 for 4 to 7 sessions; for 2 to 3 sessions it was 0.78, not statistically significant. The authors wrote that further studies are needed to find the mechanism.
Lungs and pneumonia
Kunutsor (2017) followed 1,935 men for 25.6 years and found a ratio of 0.59 for respiratory disease at 4 or more sessions. A second Kunutsor paper the same year, in 2,210 men, put the ratio for pneumonia at 0.63, with an upper confidence limit of 1.00.
What the study can’t show
Here’s what the headline won’t tell you. People who use a sauna most days may differ from those who don’t in ways the adjustments miss. An observational study can’t separate those from the sauna itself.
Four of the six papers studied men only. The saunas were traditional Finnish ones, not infrared cabins. And many results for 2 to 3 sessions a week weren’t statistically significant.
My rule of thumb: read the Kuopio numbers as the reason researchers keep studying saunas, not as a promise about what a sauna will do for you.
Bottom line: one Finnish study links frequent sauna use with lower risk of five serious conditions, most strongly at 4 to 7 sessions a week. It shows association in mostly middle-aged men, not proof. For safety guidance and the hospital sources, see the overview linked above.
Sources
- Laukkanen T, Kunutsor SK, Khan H, Willeit P, Zaccardi F, Laukkanen JA, “Sauna bathing is associated with reduced cardiovascular mortality and improves risk prediction in men and women: a prospective cohort study,” BMC Medicine, 2018;16:219: europepmc.org
- Laukkanen T, Kunutsor S, Kauhanen J, Laukkanen JA, “Sauna bathing is inversely associated with dementia and Alzheimer’s disease in middle-aged Finnish men,” Age and Ageing, 2017;46:245-249 (abstract): pubmed.ncbi.nlm.nih.gov
- Kunutsor SK, Khan H, Zaccardi F, Laukkanen T, Willeit P, Laukkanen JA, “Sauna bathing reduces the risk of stroke in Finnish men and women: A prospective cohort study,” Neurology, 2018;90:e1937-e1944 (abstract): pubmed.ncbi.nlm.nih.gov
- Zaccardi F, Laukkanen T, Willeit P, Kunutsor SK, Kauhanen J, Laukkanen JA, “Sauna Bathing and Incident Hypertension: A Prospective Cohort Study,” American Journal of Hypertension, 2017;30:1120-1125 (abstract): pubmed.ncbi.nlm.nih.gov
- Kunutsor SK, Laukkanen T, Laukkanen JA, “Sauna bathing reduces the risk of respiratory diseases: a long-term prospective cohort study,” European Journal of Epidemiology, 2017;32:1107-1111 (abstract): pubmed.ncbi.nlm.nih.gov
- Kunutsor SK, Laukkanen T, Laukkanen JA, “Frequent sauna bathing may reduce the risk of pneumonia in middle-aged Caucasian men: The KIHD prospective cohort study,” Respiratory Medicine, 2017;132:161-163 (abstract): pubmed.ncbi.nlm.nih.gov