Finnish sauna heat exposure induces stronger immune cell than cytokine responses

https://www.tandfonline.com/doi/full/10.1080/23328940.2026.2645467#abstract

166•Growtika•3h ago

Comments

gchamonlive•2h ago

> A total of 51 adults (...) were exposed to a 30-minute session of acute FSB at a temperature of + 73°C

Woah, that seems like a lot for me. I can usually stand maybe 60ºC for like 10 maybe 15 min. I don't think I'd be able to stand 30 min under 73ºC.

WhatsTheBigIdea•2h ago

I wager you are not Finnish.

gchamonlive•1h ago

Brazilian! XD

mndgs•1h ago

Not even a wager. Just out of ~100C sauna after 20 mins straight. Pretty normal, and I'm not Finnish. In that area though.

weird-eye-issue•2h ago

I was in a 110C sauna for 20 minutes today. Plus 15 minutes in a 70C one (hybrid infrared sauna). Max is 30 minutes at once at 70C. It does take some getting used to.

albertzeyer•2h ago

73°C is a bit unusual cold for a Finnish sauna. Wikipedia says:

> The temperature in Finnish saunas is 80 to 110 °C (176 to 230 °F), usually 80–90 °C (176–194 °F)

And with that temperature, I think 10–15 minutes are pretty standard.

kepeko•1h ago

73°C isn't unusual. I checked out what's source for the Wikipedia article that says it's 80 to 110°C. Oddly it's a Chicago Tribune article from 1970. I don't think I ever visited a 110°C sauna.

jaen•49m ago

110C is not that unusual in the Nordics (although way above average, it's for tougher sauna goers). I've been in one. Not most people's cup of tea though, the experience is comparable to the opposite of a long cold plunge.

MagerValp•33m ago

110 is only on the top shelf, middle or lower is much cooler. For a dry sauna you really want to be well into the 100s to get a proper kick out of it.

out_of_protocol•2h ago

Humidity is the key, Finnish style sauna is low humidity+ high temperature (85-115C is OK i think), while Russian banya-style is low temperature (60-80C with high humidity). Both of them produce about the same load on a human

orthoxerox•1h ago

Right, and Turkish-style hammam is 50C at 100% humidity. It's the only one I cannot stand.

sersi•1h ago

My problem with turkish style hammam is that unless it's extremely well maintained it often smells of mold. When I went to some nice hammams in turkey, I didn't have that problem but outside of turkey, it's often unbearable.

gchamonlive•1h ago

That's interesting. I don't have much the habit of doing sauna, as you can likely tell, so I might have tried only high humidity saunas. I'll give it a try one day with low humidity if I find one.

RakField•1h ago

This is one of the most famous public saunas in Finland: https://www.kotiharjunsauna.fi/en

If the temperature there is not close to 120°C, we are kind of disappointed.

jaen•46m ago

It's a multi-level sauna though, so it's "choose-your-own-temperature" (due to the hot air gradient), not everybody is there for the 120C experience.

SoftTalker•1h ago

The sauna at my gym is regularly over 180F and I do 30 minute sessions. It is a dry sauna however, no steam.

csr86•2h ago

In Finland we have old saying: "If liquor, tar and sauna won’t help, an illness is fatal"

brightball•2h ago

Tar?

csr86•2h ago

"Tar, acclaimed to have been formed from the sweat of Väinämöinen, a central character from the Finnish national epic Kalevala, was an important medicament to the former-day Finns. Tar actually did bear antiseptic features, which worked as a cure for infections. Lately tar has been recognised to include parts that can cause cancer, and the European Union has urged that its use should be avoided." [1]

I personally dont know how tar was used for health, but it was big export item of Finland during medieval times.

[1]https://www.helsinkitimes.fi/themes/themes/health-a-wellbein...

raverbashing•1h ago

I think you can just replace it with Vaseline (Petroleum jelly) for 99% of the benefits

actionfromafar•24m ago

That's not antiseptic

throwup238•24m ago

I only know how it’s used for psoriasis as part of the Goeckerman method [1] but allegedly there’s some general anti-inflammatory effect.

[1] https://pmc.ncbi.nlm.nih.gov/articles/PMC3735239/

xattt•23m ago

Vishnevski’s Liniment, which contains birch tar, was a common treatment for wound infections and burns in the Soviet bloc. However, this was something that individuals used because there was nothing else at hand.

Now, there are things like Fucidin, Polysporin and silver ointment for infected wounds and burns, respectively, that are safer and more effective.

Some people still swear by it, because “tradition” and probably some element of malignant patriotism too.

anjel•10m ago

Tar based, (anti)Dandruff Shampoo is still a thing

lrasinen•2h ago

Tar. Specifically wood tar,

jimmySixDOF•2h ago

Pine tar is used in topical medicine for dermatology around the world I don't think it's limited to anywhere particular.

t-3•1h ago

In Finland, they are most likely using birch tar.

lrasinen•1h ago

Nah, it's pine.

sollewitt•54m ago

Pine sap. You can get a schnapps of it, obviously.

pimeys•15m ago

I would say booze rather than liquor. Liquor sounds too fancy.

api•2h ago

Does a long hot bath do the same?

andy_ppp•2h ago

Almost certainly but most people don’t find it as enjoyable. Also the problem of keeping the bath hot enough for 20-30 mins.

weird-eye-issue•2h ago

Hot tub, onsen, etc...

Mistletoe•2h ago

If you are a man, the hot water has a deleterious effect on your testicles' ability to make sperm. But so do saunas apparently.

https://pubmed.ncbi.nlm.nih.gov/23411620/

That one was 80-90C, which is a really hot sauna.

p1esk•1h ago

Just to clarify - it’s a temporary effect - lasts for 3-6 months

Aboutplants•1h ago

Then I’m gonna start doing it on my death bed!

orthoxerox•1h ago

Finns go to sauna at least once every week and haven't gone extinct yet.

nnevod•1h ago

Still there are studies that regular sauna does decrease testosterone production. It's not hard to counter though, ice packs applied to testicles ( not direct ice, ice in a cloth) during sauna are effective for that purpose.

And maybe Finns don't go to sauna when they plan to conceive? Does Finland have a lower rate of unwanted pregnancies?

Trustable8•2h ago

It might not do the exact same, but it will have some effect. A lot of the benefit comes from the raised heart rate and opening of the blood vessels that the sauna produces, and I can expect that a warm bath would also have a similar effect. I think both are also known to reduce stress, which can help to lower blood pressure.

zemvpferreira•2h ago

Yes, if by hot bath you mean submerging yourself to neck level in 40ºC or above water for 20-30 minutes. There's no reason to believe any "heat therapy" modality is superior to another as long as you suffer equal heat stress.

For the record, if you're not acclimated, intense heat exposure is a lot more agonising than 30 minutes of exercise for less benefit. If you haven't experienced a properly tuned sauna in your life you are in for a ride. What's being studied in the literature is nothing like your standard hotel experience.

lxgr•1h ago

How are you suffering equal heat stress from being submerged in moderately warm water and breathing very hot air? I could imagine quite different effects on airways and skin, for example. "Exactly the same effect" seems like the unexpected outcome here.

> intense heat exposure is a lot more agonising than 30 minutes of exercise for less benefit

Having to do absolutely nothing other than not leaving is quite different from pushing through a physical activity that can also easily be causing all kinds of discomfort.

zemvpferreira•1h ago

Have you tried submerging yourself in moderately hot water, I wonder? And have you spent some time pondering the difference in heat transfer between convection and conduction?

out_of_protocol•1h ago

> How are you suffering equal heat stress from being submerged in moderately warm water

by the rules of this universe, you can't survive being submerged in 40C water for a prolonged period of time (even 37C would kill you as well), because humans produce heat and if you can't dispose of it you'll overheat and be dead soon enough

r0me1•8m ago

It's all about raising your core temperature, water transfers heat to the body much more efficiently than air, so water at 104F ends up raising your body core temperature as much as a dry sauna at 170F. I did some experimentation on this, I have access to a dry sauna at my gym and I track my HR and exertion levels, I did the same with the hot tub at home making sure the water temperature doesn't go below 104F and im fully submerged to the neck, 30 mins session in both cases. The graphs look pretty much identical, same HR uptrends. So as far as cardio effects and heat shock proteins I do believe they are the same, not sure if there could be any benefit to breathing dry hot air for the lungs, but so far most benefits from sauna come from raising core temp

hattmall•2h ago

>mitigate the adverse effects of low socioeconomic status

Makes me wonder how much of it is Sauna, vs just the luxury of having the time to go do nothing for ~30 minutes.

bloqs•2h ago

I nearly made a screen time comment but you are right, its facility availability and travel time issue more than anything

Jensson•1h ago

Finland has saunas everywhere, having a sauna at home isn't even expensive average people have that, its just a cultural thing its like having a toilet at home it isn't something normal people can't afford.

t-3•1h ago

Not all saunas are the same though. Traditional hotbox-ed wood burning saunas and modern electrics are the same thing but also kinda not.

Jensson•1h ago

I don't think they used wood burning saunas in this study, basically all saunas today are electric.

nine_k•1h ago

No travel time. Most Finnish houses have a sauna built in.

wood_spirit•54m ago

And Swedish houses, particularly detached houses built or renovated the 70s. Typically used for storing boxes.

Sharlin•2h ago

I just cannot fathom comments like this. I’m preeetty sure that the vast majority of people spend half an hour a day doing nothing, in front of a screen of some type. How many people do you think there are there who don’t have thirty minutes of leisure time once per week?!

Tade0•1h ago

Fresh parents without relatives to help out.

prepend•1h ago

Check out the screen time log for fresh parents.

I remember the first few months being so crazy. Feedings every two hours, and each feeding took an hour.

But still time for naps, short walks, etc. part of the survival was to work in little microbreaks when the baby was sleeping.

sersi•1h ago

I've never read as much on my kindle as when my son was born. I didn't want to use my phone so any micro break was spent reading. Much harder to do now that my son is 4 years old, I'm less sleep deprived but there's less opportunities for micro breaks when I'm with him.

skrebbel•1h ago

Huge difference between constantly being in passive alert mode waiting for the kid to wake up and cry their heart out, and proper uninterrupted “I know have x minutes for myself, no matter what” time.

Mashimo•1h ago

If it's winter, put the baby in the pram outside, while you do a quick sauna session?

lxgr•1h ago

There's a world of a difference between being able to carve out 30 actually uninterrupted minutes (and realistically more; most people don't have a sauna in their home, so they'd need to spend some time getting there and back) and being able to zone out and stare at a screen for 30 minutes in bed or on public transit.

Jensson•1h ago

> and realistically more; most people don't have a sauna in their home

Most people have a sauna in their home, this is Finland.

Sharlin•1h ago

Not having an hour of uninterrupted leisure time per day, never mind per week (most Finns don’t go to sauna every day) still sounds pretty unfathomable, except maybe in some specific circumstances like being a fresh single parent or similar. In any case, in Finland people go to sauna together with even fairly young kids (like 3+ years old), with breaks as needed of course, even most adults don’t usually spend thirty continuous minutes in a 80°C sauna.

ptero•27m ago

Virtually everyone everywhere can find free 30 minutes. And turn their devices off. Those who think they cannot would do well getting to a state where they can do this, at least 6, preferably 7 days a week.

Skipping screen time between waking up and getting up will might solve this problem for a significant fraction of the first world population. My 2c.

neves•24m ago

And it is so hot that you can't use your phone full of addicting apps that ruin your sanity.

wiseowise•1h ago

Are you even living if you're not spending every single minute breathing and shitting your work and/or kids?

u1hcw9nx•2h ago

Doing nothing for 30 minutes does not release cytokines.

choult•1h ago

But it _will_ reduce cortisol, which is known to increase the likelihood of infections

ugiox•1h ago

Less doomscrolling, less bing watching of dumb Netflix series. Sensible working hours. And a society that doesn’t demand constant reachability when being off work.

It is not a luxury. It is living with common sense.

azan_•1h ago

People with high socioeconomic status work much more and have less free time. It’s absurd to claim otherwise.

EDIT: please before being outraged at my comment have a look at actual evidence, e.g. Time and income poverty by Tania Burchardt; bottom decile compared with top decile has 12 hours more free time a week!

shadowpho•1h ago

Citation needed.

Edit: it’s absolutely not true universally and it’s ridiculous to suggest it is. Comparing averages will be very tricky as well.

azan_•37m ago

Sure - https://sticerd.lse.ac.uk/dps/case/cr/CASEreport57.pdf The difference between bottom and top decile is huge - bottom has approximately 12 hours more of free time a week! It’s consistent result that’s replicated multiple times in literature.

alphager•1h ago

People with 2 minimum wage jobs have even less time.

robertfw•1h ago

how utterly disconnected from reality you are

azan_•43m ago

I’m afraid it’s you that’s disconnected from reality. I know it’s unfashionable to actually consider evidence, but please have a look at eg Time and income poverty by Tania Burchardt. Low income people have MUCH more free time.

swiftcoder•16m ago

> People with high socioeconomic status work much more and have less free time

I think you are misrepresenting (or perhaps, misunderstanding) the conclusion of these studies. The increased "free time" is most entirely due to high unemployment at the lower end of income.

If you control for unemployment and under-employment, the graphs pretty much flatten out (as you can observe in the later graphs of the publication you linked below)

azan_•10m ago

No, I think considering only employed people is dishonest, there’s zero reason to do so. And if graph becomes flat then obviously assumption that high income people have more time is not true

nobodyandproud•41m ago

As an American: I soak in a hot tub for 30 minutes or more, at fairly high heat. At least a few times a week.

Sometimes posting on Hackernews.

It’s one of the high points of my day (the soak, not the posting).

This “I wonder” just screams lazy thinking.

cue_the_strings•2h ago

All of these studies are always performed by Finns (or SE / DK / NO + maybe Russia).

I'd love to see this (and other sauna studies) replicated by someone somewhere to the south or hotter climates in general (southern Europe, Africa, hotter parts of Asia and the Americas).

Jensson•1h ago

It is hard to study this in a place with less access to saunas.

dafelst•1h ago

Saunas are very cheap to buy and/or build, certainly within the budget of an average research grant.

usrnm•1h ago

Ever heard of hamam?

dafelst•1h ago

I have not, what is it?

alphager•1h ago

A steam sauna originating in Turkey, popular in many Arabic countries.

thesz•36m ago

It may originate from Roman's thermae: https://en.wikipedia.org/wiki/Thermae

thesz•38m ago

Hammam is not as hot as sauna and not as dry. Sauna's air temperatures can reach above 100 degress Celsius and humidity is usually relatively low (around 20%).

[1] https://en.wikipedia.org/wiki/Sauna

Hammam's temperatures are around 40-50 degrees Celsius and humidity is close to 100%.

These are very different conditions, with very different body response.

helsinkiandrew•32m ago

There’s a saying in Finland that foreign "saunas" are not true saunas at all, but rather just "untypically warm rooms".

The experiments were at 73°C which is a lot hotter than most gym/hotel/spa saunas I’ve been in outside Finland

ttiurani•7m ago

Also while 73°C is a proper sauna, there are plenty of hotter ones. 90°C is closer to what I'm used to at my apartment building's common sauna. I do take two breaks when I'm there for 30 mims though.

bilsbie•2h ago

I’ve always wondered if it raises internal body temperature? Is it basically an induced fever?

colordrops•1h ago

It does indeed increase internal temperature. Perhaps an artificial fever is part of it but I believe the science currently around heat shock proteins.

raffraffraff•50m ago

Hmm. So what about a 30 to 50 minute run wearing sweatpants / hoodie?

stevenhubertron•1h ago

Sample size is tiny fwiw.

moltar•58m ago

Anecdotal evidence. But since I started doing sauna regularly (once a week) I started to get sick less. I’m talking colds or flues. And the ones I did catch were much milder. Even with sick family members around I’m not catching it as often.

mikeodds•47m ago

hbarka•11m ago

I’m not sure if I want a response of cytokine storms. MCAS is what comes to mind.

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Finnish sauna heat exposure induces stronger immune cell than cytokine responses

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