Is a Sauna Good for a Cold? What the Evidence Actually Shows

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A sauna is better at helping you not get a cold than at doing anything about the one you already have. That is the honest version, and it is the opposite of how most people search for this.

We run an 8ft cedar barrel sauna in the backyard and use it two or three times a week, so this question is not academic for us: every winter there is a morning where the throat is scratchy and the sauna is right there. What follows is what the actual papers say, read in full rather than summarised from each other, plus where the evidence stops and guesswork starts.

Last reviewed: August 2026

We are not doctors, and none of this is medical advice. If you are ill enough to be asking whether heat is safe, ask a clinician.

What the evidence says, in four lines

• Prevention has one small supportive trial. Fifty people, six months, significantly fewer cold episodes in the sauna group.
• Treatment has none. No trial has tested sauna bathing as a treatment for an active cold.
• Frequency matters more than intensity. A couple of sessions a week, sustained for months, is the pattern in both datasets. The one with an actual number on it, 2-3 a week, is the Finnish cohort.
• Fever is the line. A sauna pushes core temperature up. A fever has already done that.

The saunas that get you the studied protocol

Prices last checked 24 August 2026 and they move. Confirm on the retailer's own page before you buy. Amazon figures were read from the quantity and add-to-cart block, not from a sponsored tile.

Pay attention to the "studied protocol" column. Every finding below came from a traditional hot-room sauna. None of it was produced in an infrared cabin or a blanket, so a blanket isn't a cheap version of this research. It's a different thing that also makes you sweat.

The one trial everybody cites, read properly

The paper is Ernst, Pecho, Wirz and Saradeth, "Regular sauna bathing and the incidence of common colds", published in Annals of Medicine in 1990. It's the single piece of direct human evidence on this question, and it's thirty-six years old.

The design: 25 volunteers took regular sauna baths, 25 controls abstained from that or anything comparable, and both groups recorded the frequency, duration and severity of their colds for six months.

The result, in the authors' own words: "There were significantly fewer episodes of common cold in the sauna group. This was found particularly during the last three months of the study period when the incidence was roughly halved compared to controls."

Then the part that gets left out of most summaries: "The mean duration and average severity of common colds did not differ significantly between the groups."

So the sauna group caught fewer colds. The ones they did catch were no shorter and no milder. That second sentence is the whole reason this article says prevention rather than treatment, and it sits in the same abstract as the headline everyone quotes.

Two more details worth having. First, the effect only became clear in the back half of the study, which fits a slow adaptation rather than a quick immune boost. Second, the authors' own conclusion is deliberately hedged: regular sauna bathing "probably reduces the incidence of common colds, but further studies are needed to prove this." Thirty-six years later, those further studies have not really arrived. PubMed also indexes it as a controlled clinical trial rather than a randomised controlled trial, which is worth knowing when you see it described online as an RCT.

One thing the abstract does not give you is the dose. It says "regular sauna bathing" and stops there. A later Finnish review describing this same study puts it at once or twice a week, which is worth having before anyone tells you the trial proves a particular frequency. It doesn't.

Fifty people is a small trial. We're not going to pretend otherwise.

What the Finnish cohort data adds

The bigger numbers come from Kuopio, and they are about respiratory illness rather than colds specifically.

Kunutsor, Laukkanen and Laukkanen followed 1,935 Finnish men aged 42 to 61 for a median of 25.6 years and recorded 379 hospital-diagnosed cases of respiratory disease, defined as COPD, asthma or pneumonia. Adjusted for the usual confounders, the hazard ratios were 0.73 (95% CI 0.58-0.92) for men taking 2-3 sauna sessions a week and 0.59 (95% CI 0.37-0.94) for four or more, both compared with one session a week or fewer. For pneumonia on its own the figures were 0.72 (0.57-0.90) and 0.63 (0.39-1.00).

Three caveats you'd want flagged. It's observational, so it shows association and not cause, and men who sauna four times a week in Finland may differ from men who don't in ways no adjustment fully catches. It was published as a research letter in the European Journal of Epidemiology, which is a short format. And the population is middle-aged Finnish men, which is a narrow slice of humanity to generalise from.

What it does do is point the same direction as the trial, and it is the only one of the two carrying a number. The benefit shows up at a couple of sessions a week, sustained over years. Nothing here is about a single session.

Where the "steam clears it out" idea runs out

The intuition is old and reasonable: rhinovirus replicates better at the cooler temperatures found in the nose, so warm humid air ought to make life harder for it. That is the logic behind steaming over a bowl, and it is why people reach for a sauna or a steam room when they are blocked up.

It has been tested. A Cochrane review by Singh and colleagues, last updated in 2017, pooled six trials from five publications with 387 participants and concluded that "the current evidence does not show any benefits or harms from the use of heated, humidified air delivered via the RhinoTherm device for the treatment of the common cold." The one included study that examined viral shedding in nasal washings found no significant difference between treatment and placebo (OR 0.47, 95% CI 0.04 to 5.19), and two studies reported minor adverse events.

That's not a sauna trial, and the delivery method is a specific device rather than a hot room. But it's the closest anyone has come to testing the mechanism, and it came back neutral. If warmed humid air straight up the nose does not shift a cold, a hot room is unlikely to be doing something more dramatic.

Feeling better is still real. Being congested is miserable, and twenty minutes where your sinuses are not doing that is worth having. Just call it symptomatic relief that lasts as long as the heat does, because that is what the evidence supports.

Why a fever changes the calculation

Here's the honest state of play. We could not find a trial that put febrile people in a sauna. What we did find is a peer-reviewed review that tells you to stay out anyway.

Kukkonen-Harjula and Kauppinen's review in the International Journal of Circumpolar Health lists contraindications to sauna bathing that include "acute infectious diseases with fever" and, separately, "fever for any reason". That is a published recommendation rather than something we worked out ourselves, and it is the most direct answer the literature gives to this question.

It is still expert guidance in a review paper rather than a trial result, and the distinction matters. The cardiac contraindications are narrower and better evidenced: Hannuksela and Ellahham's review in the American Journal of Medicine lists "unstable angina pectoris, recent myocardial infarction, and severe aortic stenosis", and notes that sauna bathing is safe for most people with stable angina or an old infarction. Fever is not on that one.

So: a published recommendation to stay out with a fever, and no trial in either direction. The physiology is why that recommendation is easy to agree with.

The numbers come from that same review. Core temperature measured from the esophagus rises in the hot room to about 38C, then accelerates toward 39C. Heart rate "accelerates up to twice the resting rate and even more". Sweating costs "about 0.5 to 1 kg" of body weight in a session.

Now put a fever underneath that. Your set point is already raised, your heart rate is already up, and if you've been eating badly and drinking less than usual for two days, you start the session down on fluid. All three numbers get worse from a higher baseline. That's our reasoning rather than a trial result. It lands in the same place the published contraindication already does, which is the useful part.

One more item, because people ignore it: Hannuksela and Ellahham state that alcohol consumption during sauna bathing "increases the risk of hypotension, arrhythmia, and sudden death, and should be avoided". Kukkonen-Harjula and Kauppinen are more measured, flagging the hypotension risk while noting that bathing combined with heavy drinking did not provoke dysrhythmias in healthy young men. Take the cautious one. A hot toddy and a sauna is a bad combination, and it is exactly the combination people reach for when they have a cold.

If you have a mild cold and want to use your sauna anyway

Plenty of people will, and a head cold with no fever is a different situation from flu. If that is you, and you have no fever, no chest symptoms and no cardiac history, we would keep it conservative:

1. No fever, no session. If you are running a temperature, that decides it.
2. Cut the duration. Whatever your normal session is, halve it.
3. Drink before, not just after. You are giving up 0.5 to 1 kg of fluid in a normal session and you are probably already behind.
4. Skip the cold plunge afterwards. Contrast work is a bigger cardiovascular load than heat alone, and this is not the week for it.
5. Go alone, or don't go. Public and shared saunas are the obvious point here. Being contagious in a small hot box with other people is a choice about them, not you.

If you feel worse in there, get out. That's information, not a failure of discipline.

What to buy if you want the preventive effect

The frequency is the active ingredient. A couple of sessions a week, sustained, is what both datasets point to, and the cohort puts the number at two or three, which means the purchase decision is really "what will I still be using in February", not "what has the highest maximum temperature".

Harvia KIP 6kW electric heater — ~$1,216

Best for: the cheapest honest route to a real Finnish sauna.

Pros: dial controls with no app or subscription in the way; sauna stones included, so you can throw water and get the humid burst that a dry cabin cannot; stainless construction; sold by Harvia US on the listing we checked rather than a third-party reseller.

Cons: it is a heater, not a sauna. You need a room, an insulated build and, at 6kW on 240V, an electrician and a dedicated circuit. That is a real project and a real second cost.

The reason it is our top pick anyway: a heater and a converted shed or spare room gets you the exact thing the research studied, at roughly a fifth of the price of a finished barrel. If your build stalls, the heater is not the reason.

HigherDOSE Infrared Sauna Blanket — ~$699

Best for: apartments, and anyone whose real constraint is space.

Pros: cheapest way to get regular heat exposure into a week; folds away; no installation, no circuit, no permit.

Cons: none of the cold or respiratory research was done in one of these. It is infrared body-contact heat with no hot air to breathe, which is the specific thing the congestion argument depends on. Getting out mid-session takes a moment rather than a step.

We do not own one, so we will not pretend to a view on how it feels over a winter. What we will say is that the evidence in this article does not transfer to it, and any page telling you a blanket delivers the Ernst result is filling a gap with hope.

Golden Designs "Arosa" outdoor barrel — ~$5,999

Best for: buying the finished thing and putting it in the garden.

Pros: Pacific cedar barrel, traditional heater, wet or dry use; the barrel shape is genuinely efficient to heat because there is less dead air above your head than in a cube.

Cons: you still need a level pad and an electrical run to the end of the garden, and both are separate jobs with separate costs that the sticker price does not cover.

This is the closest thing on the list to what we actually own, so the note we can make first-hand is this one: a barrel outdoors gets used more in winter than we expected, because the walk out through the cold turns into part of the appeal rather than the obstacle it looks like in October.

SaunaLife E8G Ergo barrel — ~$10,408

Best for: four to six people, which usually means a household that will actually hit three sessions a week between them.

Pros: thermo-spruce rather than cedar, which is more dimensionally stable in a wet-dry cycle; heater and stones included; the Ergo layout gives usable bench space for the stated capacity rather than nominal capacity.

Cons: the price, and stock was down to one unit on the listing we checked, so availability moves. At this level you are also into a delivery and siting job rather than a weekend.

Nothing about a bigger sauna makes the preventive effect stronger. It makes it more likely that a family of four all use it, which is the same thing arriving by a different route.

Frequently asked questions

Is a sauna good for a cold?

The evidence supports prevention rather than treatment. In the 1990 Annals of Medicine trial, 25 people taking regular sauna baths had significantly fewer episodes of common cold over six months than 25 controls, with the incidence roughly halved in the final three months. The same trial found no significant difference in duration or severity. So it is a case for the habit, not for the day your throat starts hurting.

Can you use a sauna with a fever?

We would not, and we would ask a clinician first. A fever means your body has already raised its own set point, and a sauna raises core temperature further, to around 38C and then toward 39C, with heart rate up to roughly double resting and 0.5 to 1 kg of fluid lost. A 2006 review in the International Journal of Circumpolar Health lists "acute infectious diseases with fever" and "fever for any reason" among the contraindications to sauna bathing, so this is not only our opinion. No trial we could find tested sauna use in acutely febrile people. That is missing evidence, not permission.

Does a sauna kill a cold virus?

No published trial shows that. The mechanism sounds plausible because rhinovirus replication is temperature-sensitive in the lab, but when heated humidified air was tested in humans, the 2017 Cochrane review of six trials and 387 participants found no benefit for treating a cold, and the one included study that measured viral shedding found no significant difference against placebo.

Is a steam room better than a sauna for congestion?

It may feel better, and that is not nothing. It has no trial evidence behind it. If you want humidity from a traditional sauna, water on the stones gets you humid air in bursts, which is why a Finnish sauna sits between a dry cabin and a steam room in practice. Our steam room vs sauna comparison goes through the differences properly.

How often do you need to use a sauna to reduce colds?

A couple of sessions a week, every week. The only frequency with numbers attached comes from the Finnish cohort of 1,935 men: hazard ratios of 0.73 at 2-3 sessions a week and 0.59 at four or more, against one or fewer. The 1990 trial publishes no frequency in its abstract, and a later Finnish review describes it as once or twice a week, so it can't settle the dose question. What it does show is that the separation from controls only appeared in the final three months.

Can you use an infrared sauna when you're sick?

The cold and respiratory research used traditional hot-room saunas, so none of it transfers to infrared automatically. An infrared cabin heats you at a lower air temperature, which some people tolerate better, but that is a comfort argument. The fever caution applies the same way, and more so in a blanket.

Is a sauna good for the flu?

Flu usually brings fever, aches and real fatigue, and no sauna study tested it as a treatment. The prevention signal in the Finnish data covered hospital-diagnosed respiratory disease including pneumonia, where 2-3 sessions a week carried a hazard ratio of 0.72. Fever, breathlessness or chest pain are reasons to stay out and call a doctor.

Our Verdict

If we were starting again with this specific goal, we would buy the Harvia KIP 6kW heater at ~$1,216 and put it in a room we already had, because the thing the Finnish cohort measured is a traditional hot room used two or three times a week, and that is the cheapest honest way to own one.

What we would not do is buy anything because of a cold. The Ernst trial is fifty people and thirty-six years old, its own authors said further studies were needed, and those studies never really came. The Finnish cohort is bigger and points the same way, but it is observational and it is about hospital-diagnosed respiratory disease, not sniffles. Put together, they justify a habit. They do not justify a purchase made in week one of a head cold, and they say nothing at all in favour of climbing into heat while you have a temperature.

We use ours through the winter because we like it. Fewer colds, if we get them, are a bonus we would struggle to prove.

Read next: how often you should use a sauna for the frequency question on its own, steam room vs sauna if the congestion angle is what brought you here, and the Huberman sauna protocol for how the frequency research gets applied in practice. Every review we have published sits in the saunas hub, and more on who writes this site is on our about page.