The idea is old and appealing: get hot, sweat hard, and the cold leaves with the sweat. People have tested it. It doesn’t work that way.
This article separates two questions that get mixed up: using a sauna to treat an illness you have, and using one regularly to get sick less often. It sits under our overview of sauna health benefits. This is general information, not medical advice.
Short answer: don’t use a sauna to treat a cold, flu, or fever. A controlled trial found no meaningful effect on cold symptoms, and medical sources advise staying out while you are ill. Regular sauna use while healthy may reduce how often you catch colds, but that evidence is small and old.
Treating a cold: the trial
Researchers in Berlin ran a randomized trial with 157 people who had just come down with a cold. Both groups sat in a hot sauna wearing winter coats. One group inhaled the hot, dry air. The control group inhaled dry air at room temperature. They did this for 3 days and were followed for 4 more.
The result, in the authors’ words: “Inhaling hot air while in a sauna has no significant impact on overall symptom severity of the common cold.”
A few secondary measures favored the hot-air group, such as medication use on the first day. The main outcome did not. One trial with an unusual design isn’t the last word, but it is the best direct test I found.
Fever and flu: stay out
Cleveland Clinic is direct. Dr. Melissa Young, a functional medicine specialist, says: “Don’t expect to sweat out a fever or an infectious illness like the flu.” The clinic’s article explains that sitting in the heat stresses a body that is already working to recover, which may make you feel worse. It lists illness among the times to avoid the sauna.
Medical News Today gives the same rule: “People who are ill should also wait until they recover before using a sauna.”
There is a second reason. A sauna makes you sweat out fluid, and being sick already raises your need for it.
Preventing colds: a maybe
The prevention claim has a different study behind it. In 1990, researchers assigned 25 volunteers to regular sauna bathing and 25 to a control group that abstained.
They reported “significantly fewer episodes of common cold in the sauna group,” and concluded that “regular sauna bathing probably reduces the incidence of common colds.” They also said more studies were needed.
Fifty people, more than 30 years ago. Cleveland Clinic’s Dr. Amy Zack sums up where that leaves things: “Further research is needed to substantiate claims of improvement in the immune system.”
What about congestion?
A hot room can feel good on a stuffed nose for a few minutes. That is comfort, not treatment, and the Berlin trial suggests the comfort doesn’t shorten the cold. Cleveland Clinic’s home advice for a cold is rest and fluids.
The two questions side by side
| Question | Best evidence found | Answer |
|---|---|---|
| Will a sauna treat my cold? | 2010 randomized trial, 157 people | No significant effect on overall symptoms |
| Should I sauna with a fever or flu? | Cleveland Clinic guidance | No |
| Will regular sauna use prevent colds? | 1990 trial, 50 people | Probably, but weakly supported |
Sharing a sauna while sick
One point the studies don’t cover, so it is my own: a home sauna is a small closed room. If you are contagious, the people who use it after you breathe the same air and sit on the same benches. Wait until you are well.
When you are better
Go back gradually. The usual limits apply: about 15 to 20 minutes, water before and after, and leave if you feel dizzy. If you are shopping for a sauna to use year-round, the home sauna buying guide covers the choices.
See a doctor if your symptoms get worse or you have a high fever. A sauna is not a substitute.
Bottom line: a sauna won’t cure a cold, and it is a bad idea with a fever. Rest, drink, and come back to the heat when you are well.
Sources
- Pach D, Knöchel B, Lüdtke R, Wruck K, Willich SN, Witt CM, “Visiting a sauna: does inhaling hot dry air reduce common cold symptoms? A randomised controlled trial,” Medical Journal of Australia, 2010 (abstract): pubmed.ncbi.nlm.nih.gov
- Ernst E, Pecho E, Wirz P, Saradeth T, “Regular sauna bathing and the incidence of common colds,” Annals of Medicine, 1990 (abstract): pubmed.ncbi.nlm.nih.gov
- Cleveland Clinic, “6 Possible Benefits of Infrared Saunas,” October 9, 2026: health.clevelandclinic.org
- Cleveland Clinic, “Get Your Sweat On: The Benefits of a Sauna,” August 12, 2024: health.clevelandclinic.org
- Medical News Today, “Sauna: Health benefits, risks, and precautions,” medically reviewed, last updated June 27, 2023: medicalnewstoday.com