Is a Sauna Good for a Cold? What the Evidence Says (and When to Skip It)

Is a sauna good for a cold? Partly. Regular sauna use over months may mean you catch fewer colds in the first place, but sitting in a sauna once you're already ill won't cure anything or shorten the cold. If you've got a mild head cold with symptoms above the neck (a runny or blocked nose, sneezing, a slightly sore throat) and no fever, a short, cooler session may feel soothing and, in a steam room especially, can ease congestion for some people. Skip it entirely if you have a temperature, flu symptoms, a chesty cough or you're already dehydrated, because heat stress on top of a fever is the last thing your body needs.

Below is what the research actually shows, how to do a sauna safely if you decide to go, and when it's time to stop self-treating and speak to your GP.

What the research says

The honest summary is that the evidence is thin, small and mostly old. That doesn't make it worthless, but it does mean you should treat any big promises about saunas "boosting immunity" with suspicion.

Regular sauna use and catching fewer colds

The study everyone points to is an Austrian trial from 1990 (Ernst et al., Annals of Medicine). Researchers put 25 volunteers on a regular sauna routine and compared them with 25 people who didn't sauna, tracking colds for six months. The sauna group had significantly fewer colds, and in the last three months their rate was roughly half that of the controls.

Two catches. The colds people did get lasted just as long and felt just as bad in both groups, so the sauna didn't make illness milder. And 50 people is a tiny sample; the authors themselves concluded that saunas "probably" reduce colds and that more studies were needed. Thirty-plus years later, a 2018 systematic review of regular dry sauna bathing still described the evidence for immune benefits as scant (Hussain and Cohen, Evidence-Based Complementary and Alternative Medicine).

So a sauna habit is a reasonable thing to keep up through winter if you enjoy it. Just don't expect it to replace handwashing.

Using a sauna once you already have a cold

This is where the evidence is weakest. The same 2018 review found only one trial that tested sauna heat on people with an active cold: 157 adults in Germany breathed either hot 90°C sauna air or cool 24°C air through a face mask while sitting in a sauna. The hot-air group reported slightly lower symptom scores on day 2, but the difference had vanished by days 3, 5 and 7, and the reviewers judged the effect negligible. Use of cold medication was lower on day 1 (3% versus 15%) and the same afterwards.

In plain terms: a sauna might make you feel a bit better for a day. It won't kill the virus, and you'll still be ill for roughly as long. The NHS says most colds improve within 1 to 2 weeks whatever you do (NHS: common cold).

The "above the neck" test

There's no formal medical rule for sauna use with a cold, but the common-sense check many coaches use for exercise works well here too. If your symptoms are all above the neck and you feel more or less yourself, a gentle session is a personal choice. If they've spread below the neck, stay out.

People with heart conditions, low blood pressure, pregnancy or a weakened immune system should check with a GP before using a sauna at any time, and particularly when unwell.

How to use a sauna safely with a mild cold

If you've passed the above-the-neck test and want the warmth, change your usual routine. Being ill lowers your tolerance, and the goal is comfort, not a heat challenge.

• Drink first. Have a large glass of water beforehand and another afterwards. A cold already dries you out through a runny nose and mouth-breathing, and you'll sweat on top of that. The NHS advice for colds starts with rest and plenty of fluids.
• Go shorter. Five to 10 minutes is plenty, and stick to one round. If you normally do three rounds of 15 minutes, this is not the day. Our guide to how long you should stay in a sauna covers normal session lengths.
• Go cooler. Sit on the lower bench, where it's noticeably cooler, or turn a home sauna down. A Finnish sauna usually runs at 70 to 100°C; for a cold, the bottom of that range is more than enough. See sauna temperature for typical settings by type.
• Get out early. A pounding head, light-headedness or a racing heart means stop, not push through.
• Cool down gently. Skip the cold plunge this time. Let your body temperature come down slowly, rest afterwards and get to bed early.

Steam room or dry sauna for a blocked nose?

For congestion, steam wins. The NHS suggests breathing in steam to ease a blocked nose, and its example is simply sitting in a bathroom with a hot shower running. A steam room is a bigger, hotter version of that, typically around 40 to 45°C with humidity close to 100%.

A traditional dry sauna has low humidity, often 10 to 20%, unless you throw water on the stones (löyly), which gives a short burst of moist heat. Some people find very dry, hot air irritates an already sore throat or nose. If stuffiness is your main complaint, a steam room or a hot shower is the gentler option. Our sauna vs steam room comparison goes into the differences in more detail.

One warning carried straight from the NHS page: children shouldn't breathe steam from a bowl of hot water because of the scalding risk.

Infrared vs traditional sauna when you're ill

Infrared saunas heat your body more directly and run cooler, usually 45 to 65°C, compared with 70 to 100°C in a traditional sauna. That lower air temperature can feel easier to tolerate when you're under the weather, and many people find it less harsh on the airways than a hot Finnish room.

The trade-off is that infrared cabins and tents are dry, so you get none of the steam benefit for a blocked nose. There's no research comparing the two types for colds specifically. Pick whichever you tolerate better, keep the session short, and read our infrared vs traditional sauna guide if you're deciding which kind to buy.

Hygiene in shared saunas

This is the part people forget. You're infectious from a few days before symptoms start until they've gone, usually 1 to 2 weeks, and cold viruses can survive on hands and surfaces for 24 hours, according to the NHS. A gym or spa sauna is a small, enclosed room with shared benches, door handles and ladles, often with people sitting shoulder to shoulder.

If you have a cold, the considerate choice is to give the communal sauna a miss until you're better. If you do go, sit on your own towel, don't share towels or water bottles, wash your hands before and after, and catch any sneezes in a tissue you bin straight away. Our sauna etiquette guide covers the wider rules for UK gyms and spas.

A home sauna is the easier option

Having your own sauna solves the hygiene problem completely and lets you control the temperature and session length. A portable steam sauna is the cheapest way to get moist heat at home, and that's the type most relevant to congestion. We've researched the SereneLife portable steam sauna, a budget tent with a 4-litre steamer that you sit in with your head outside, which keeps the heat milder on your airways.

Check SereneLife price on Amazon

If you'd rather have dry infrared heat, the CONLONS infrared sauna tent is roomier than most portable tents. For cabins, blankets and everything in between, see our round-up of the best home saunas in the UK and the wider recovery hub.

When to see a GP

A cold normally sorts itself out, and antibiotics won't help because it's viral. The NHS advises asking your GP for help if:

• your temperature is very high, or you've had a high temperature for more than 3 days
• your symptoms get worse, or haven't improved after 10 days
• you feel short of breath or have chest pain
• you've had a cough for more than 3 weeks
• you have a long-term medical condition or a weakened immune system
• you're worried about a child's symptoms

If any of those apply, the sauna can wait. Rest, fluids and a pharmacist's advice will do more for you this week than heat will.

Recommended reads

1. How long should you stay in a sauna?
2. Sauna vs steam room: which should you use?
3. Sauna temperature: how hot should it be?
4. Sauna etiquette for UK gyms, spas and home saunas
5. The best home saunas in the UK