Twenty-five regular sauna users caught fewer colds than 25 non-users over six months
The line "saunas halve your colds" traces back to this 1990 Annals of Medicine trial. It followed 50 volunteers, and the halving showed up in the last three months.
The paper
Regular Sauna Bathing and the Incidence of Common Colds
Ernst E, Pecho E, Wirz P, Saradeth T. Annals of Medicine, 1990;22(4):225-227.
See the study at a glance
- Design
- Controlled trial (allocation not stated in the abstract)
- People
- 50 volunteers
- Who they were
- Adult volunteers of both sexes. Twenty-five took regular saunas, and 25 others stayed away from saunas and similar treatments.
- What they did
- Regular sauna bathing for six months while both groups recorded their colds. The abstract doesn't give the sauna temperature or say how often people went.
- How long
- Six months
These numbers came out of it
Roughly half
In the last three months of the study, the sauna group caught colds at roughly half the rate of the comparison group.
Fewer
Over the full six months the sauna group had fewer colds, and the authors reported the difference as significant.
No difference
The colds people did catch lasted as long and felt as bad in both groups.
25 per arm
Each group had 25 people, and we can't tell from the abstract whether they were randomly assigned.
The researchers did this
Edzard Ernst and colleagues recruited 50 volunteers. Twenty-five took up regular sauna bathing, and the other 25 stayed away from saunas and similar treatments as a comparison group.Source 1 · Clinical trialRegular Sauna Bathing and the Incidence of Common ColdsErnst E, Pecho E, Wirz P, et al.. Annals of Medicine, 1990.Read the paper ↗PubMed ↗ For six months both groups recorded each cold and how long and how bad it was.
The sauna group had significantly fewer colds. Most of the difference came in the last three months, when they caught colds at roughly half the rate of the comparison group. Colds lasted as long and felt as bad in both groups.
The authors concluded that regular sauna bathing probably cuts down on colds and called for more studies. A 2018 textbook review found no later trial of sauna or hot baths for preventing colds.Source 2 · ReviewViral Upper Respiratory InfectionBarrett B. Integrative Medicine, 2018.Read the paper ↗
The study can't tell you these things
- The abstract doesn't say the groups were randomized, and a 2018 review calls the trial nonrandomized.Source 2 · ReviewViral Upper Respiratory InfectionBarrett B. Integrative Medicine, 2018.Read the paper ↗
- People logged their own colds without any lab test for a virus.
- People knew which group they were in, and the control group had no sham treatment.
- We couldn't get the full text, so we don't know the sauna schedule or temperature.
- Fifty people is a small base for a claim about everyone's colds.
People quote it like this
People cite it for "saunas halve your colds," and the halving covered the last three of the six months. A 2020 review went further and called it randomized controlled trial evidence that regular saunas halve respiratory viral infections.Source 3 · Hypothesis paperTurning up the heat on COVID-19: heat as a therapeutic interventionCohen M. F1000Research, 2020.Read the paper ↗PubMed ↗ The abstract describes colds with no lab confirmation and doesn't say the groups were randomized. The Finnish sauna researchers' 2024 review got the timing right and put the halving in the final three months.Source 4 · ReviewThe multifaceted benefits of passive heat therapies for extending the healthspan: A comprehensive review with a focus on Finnish saunaLaukkanen JA, Kunutsor SK. Temperature, 2024.Read the paper ↗PubMed ↗
From our sister magazine
Sauna Monthly explains how to make a regular sauna habit stick
We cited these sources
- 01Ernst E, Pecho E, Wirz P, Saradeth T. Regular Sauna Bathing and the Incidence of Common Colds. Annals of Medicine. 1990;22(4):225-227. doi:10.3109/07853899009148930 PMID 2248758
- 02Barrett B. Viral Upper Respiratory Infection. Integrative Medicine. 2018:170-179.e7. doi:10.1016/B978-0-323-35868-2.00018-9
- 03Cohen M. Turning up the heat on COVID-19: heat as a therapeutic intervention. F1000Research. 2020;9:292. doi:10.12688/f1000research.23299.2 PMID 32742639
- 04Laukkanen JA, Kunutsor SK. The multifaceted benefits of passive heat therapies for extending the healthspan: A comprehensive review with a focus on Finnish sauna. Temperature. 2024;11(1):27-51. doi:10.1080/23328940.2023.2300623 PMID 38577299