Finnish sauna heat exposure induces stronger immune cell than cytokine responses

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

by Growtika • 4 months ago

386 282 4 months ago

gchamonlive3• 4 months 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• 4 months ago

I wager you are not Finnish.

gchamonlive3• 4 months ago

Brazilian! XD

mndgs• 4 months 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-issue3• 4 months 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• 4 months 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• 4 months 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.

out_of_protocol2• 4 months 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

orthoxerox2• 4 months ago

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

gchamonlive3• 4 months 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• 4 months 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.

jaen2• 4 months 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.

KellyCriterion10• 4 months ago

This temperature cheating is one of the things I see very often in Gyms & public places: They announce with "fin sauna 90°", and then its only 80 or 82,so stealing some performance :-D

SoftTalker• 4 months ago

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

csr862• 4 months ago

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

brightball2• 4 months ago

Tar?

csr862• 4 months 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...

lrasinen2• 4 months ago

Tar. Specifically wood tar,

sollewitt• 4 months ago

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

ascii0eks844• 4 months ago

Not the tapes, tar pit tar, the black thingy used in boats. And now that I read what's the translation it seems to be asphalt actually.

pimeys• 4 months ago

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

yeah879846• 4 months ago

It's call alcohol

KellyCriterion10• 4 months ago

Is it true that new houses are constructed/architectured as "sauna first" and then everything else is planned around the sauna?

or is that just an urban legend claim?

incognito_robot• 4 months ago

Trust your instincts.

ascii0eks844• 4 months ago

While it's true something like 90% of the accomodation have a sauna it's not like everything is planned around it. It's more like that it's the ONLY well soundproofed space, with nice atmosphere, that makes life enjoyable when your neighbors suck.

silvertaza• 4 months ago

Not around the sauna per se, but sauna is often built first because it serves as a place to live while you're building the house!

jedberg• 4 months ago

I have no idea if that claim is true, but what I did love about visiting Finland was the even the small apartment I rented had a sauna in it! It seems like it's a non-negotiable for even the smallest accommodations.

nextos• 4 months ago

Even small brand new apartments tend to have their own sauna, which is quite impressive.

amelius2• 4 months ago

Are there any scientific results showing that this helps?

debo_• 4 months ago

I'm not even Finnish and I came here to post this.

aivisol• 4 months ago

Checked life expectancy in Finland: I guess you use booze to offset the positive effects of sauna :)

Tommix11• 4 months ago

The tar ointment I bought in Mariehamn is fantastic for healing small infected cuts and bruises. Highly recommend.

api• 4 months ago

Does a long hot bath do the same?

andy_ppp• 4 months 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-issue3• 4 months ago

Hot tub, onsen, etc...

Mistletoe• 4 months 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• 4 months ago

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

Trustable8• 4 months 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.

zemvpferreira3• 4 months 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.

lxgr4• 4 months 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.

amarant• 4 months ago

The standard hotel experience is sitting wrapped in a towel and longing for my winter coat! Actually I would probably feel similarly in this study, 73°c is really cold for sauna. 90°c-100°c is the sweet spot

hattmall• 4 months 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• 4 months ago

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

Jensson4• 4 months 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.

nine_k• 4 months ago

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

Sharlin2• 4 months 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• 4 months ago

Fresh parents without relatives to help out.

lxgr4• 4 months 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.

wiseowise• 4 months ago

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

pkilgore• 4 months ago

You "cannot fathom" the privilege your have or life experience you lack to believe this unconditionally.

u1hcw9nx• 4 months ago

Doing nothing for 30 minutes does not release cytokines.

choult• 4 months ago

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

ugiox3• 4 months 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.

mrgoldenbrown2• 4 months ago

Sensible working hours is a luxury for many people, at least in the United States. Especially the ones considered low socioeconomic status. 40 hours a week at minimum wage will barely pay the median rent in my state. That leaves nothing for food, health care, utilities, transportation, etc.

azan_17• 4 months 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• 4 months 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.

alphager2• 4 months ago

People with 2 minimum wage jobs have even less time.

robertfw• 4 months ago

how utterly disconnected from reality you are

swiftcoder5• 4 months 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)

rfrey2• 4 months ago

Your point is even more graphically illustrated if you compare the extremes... Say trust fund babies to homeless people. The trust fund people spend at least ten hours a week reviewing investment and disciplining their entourage, whereas homeless people's time is completely their own.

grg02• 4 months ago

That claim doesn't stand a chance? It's obviously non-linear; once you're really up there in the higher echelons of wealth, I'm sure you get a lot of time back.

rexpop5• 4 months ago

Imagine two kids get the weekend off from school. One kid gets money to order pizza, ride a fast taxi to the movies, and pay someone else to clean their room. They get to spend the whole weekend just playing and having fun. The other kid has no extra money. They have to spend their weekend cleaning the house, cooking meals from scratch, walking a long way just to get anywhere, and babysitting their little sibling.

On a piece of paper, both kids had the exact same amount of "free time" away from school. But in real life, the second kid was actually working the whole time.

Wealthy people can buy back their time by paying for things like daycare, grocery delivery, takeout, and house cleaning. People with less money can't afford to buy these shortcuts, so they have to do all this unpaid work themselves. This eats up their free hours.

Jobs that pay less often change workers' schedules at the last minute, so they can never plan their days or get enough sleep. They also might have to ride slow public buses for a long time to get to work. This means their free time is broken into stressful little pieces, like waiting at a bus stop or waiting for an unexpected shift to start.

Even when they do get an hour to sit down, they are usually very stressed about paying bills. When your brain is constantly worrying about survival, taking a break doesn't feel relaxing, and can even make you feel more anxious.

So, while wealthy people might officially work more hours at their jobs, the money they make lets them buy real, relaxing rest. People with less money might have fewer official job hours, but their "free time" is entirely stolen by unpaid chores, unpredictable schedules, and the stressful work of just trying to survive.

The long and short of it is that poor people work longer hours; they simply receive less formal recognition for it.

Your attempts to hide these facts and paint poverty as enviable in this dimension are disgustingly inhumane.

nobodyandproud3• 4 months 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.

KellyCriterion10• 4 months ago

just make sure your charger is faaar away from the tube, please. (and thats also true for your phone charger :-)

bitexploder3• 4 months ago

As an American, I built a proper sauna. Love it.

gjulianm6• 4 months ago

That might have an effect, but these studies are probably mostly selecting for people who can tolerate a hostile environment for longer, which are usually healthier. I find it unlikely that sauna alone explains the fantastic, almost miraculous hazard ratios that these studies report.

LorenPechtel4• 4 months ago

Unfortunately, yes, just about everything beyond the basics in longevity stuff has that as a possible confounder. Sauna is a fairly passive thing, though, I would expect less of an effect.

nextlevelwizard6• 4 months ago

Who doesn’t have 30 minutes per week to do nothing? I am genuinely asking.

grg02• 4 months ago

I don't know but I'm feeling for this guy right now.

cue_the_strings• 4 months 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).

Jensson4• 4 months ago

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

dafelst2• 4 months ago

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

usrnm• 4 months ago

Ever heard of hamam?

dafelst2• 4 months ago

I have not, what is it?

thesz2• 4 months 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• 4 months ago

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

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

ttiurani2• 4 months 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.

ludicrousdispla• 4 months ago

you can sous vide beef and pork at a lower temperature than that

KellyCriterion10• 4 months ago

73° hot?

Here in mainland Europe, a "classic fin sauna" is usually at least 90°++

kikimora• 4 months ago

Anything beyond 90 C is not a sauna :) Better to have 90+ and hot steam as in Russian sauna (banya) :)

tauntz2• 4 months ago

As an Estonian, anything below 80°C is considered a "kids sauna". 80°C - 90°C is a cold-but-workable sauna and proper sauna starts from 90+°C. I'd assume it's the same in Finland as we share a lot of the sauna culture.

sumea• 4 months ago

And also replicated with participants not used to high temperatures inside a typical Finnish sauna. As the study said such people are very difficult to find in Finland. But I wonder if a person who has never been to a real sauna would tolerate this study protocol (2*15 min at 73° Celsius) without any training.

Sauna and hot climates may sound counterintuitive, but it has been tested by most Finns that when you come out of a hot sauna any outside temperature feels cool.

piva00• 4 months ago

I'm an immigrant in Scandinavia, originally from a hot country, in my experience a 73C steam sauna is quite tolerable for a 2*15 min session.

The first time I was in a sauna after moving was a bit harder than after getting used to it but doable.

Nowadays I just love them, my friends and I built a couple of saunas to leave by the lake in their summerhouses, the cravings of going from hot -> very cold, and back to the heat is hard to explain, and I totally recommend it.

anthk• 4 months ago

Northern Spaniard there, bring a Saunaa lover Finn with one of these climate-change induced hours at 43C at some day or two in Summer... in the Atlantic, in Bilbao, which is... inside a valley.

I've been in saunas at 60-70C and the feeling inside was much bearable because of the lack of humidity than 43C under a climate closer to UK than inner/Mediterranean Spain.

gjulianm6• 4 months ago

I doubt they would replicate it or any of the magical effects of saunas. Lots of the sauna studies suffer from the same issue where people self-report sauna usage rather than being assigned randomly to a treatment group. In countries where saunas are readily accessible and most people are under the impression that the more you use sauna the healthier you are, the ones that use the sauna less are probably because they tolerate it far worse. And that's probably related with age, comorbidities, physical condition, etc.

Basically, the sauna studies are probably mostly discovering that "healthier people can stand sauna longer". In countries where most people don't stand sauna for more than a few minutes, that self-selection bias won't exist.

fy20• 4 months ago

Also location. In my country, saunas at home aren't as common in Finland, but basically every gym has one. So the people that use the sauna the most, are likely to be the most active.

curiousgal• 4 months ago

I don't know about that. As in yes I agree but that seems to apply to Western countries in general. For example in Tunisia, people go to public baths at least once a week and part of that involves sitting in a hot steamy room for 30+ minutes. So here you have an example for a population that does use sauna (in a way) but aren't relying on self-reporting.

lukan3• 4 months ago

If you want to experience positive health effects from sauna, you don't have to set records in heat and duration. You just get hot and sweat as much as you feel is fine. So you can do it in almost all conditions. Sweating out bad stuff from your body, activating the blood flow, unless you are at risk of a aneurysm - of course it is beneficial, even though it doesn't magically turn your health around. But a proper sauna and ice bath do revive and make you feel reborn. Try it at least at some point and then you can judge if it did not make you feel more alive and healthier and that all the studies around it a "probably bullshit".

Findecanor• 4 months ago

What about Japanese hot springs? ("onsen") Those are typically around 40°C but could be up to 60°C. Because it is hot water and not hot air the temperature would be transferred differently to the body though, so I don't think the numeric temperature is directly comparable.

Onsen baths are taken all year round: including summers that get hotter than in Finland, but especially enjoyed in winter.

pezezin• 4 months ago

I am a Spanish guy currently living in Japan, and honestly I hate sauna but love onsen. Most on my Spanish colleagues seem to think the same. I guess the main factor being that both Spain and Japan are have really hot summers, so why would you get in a hot room to sweat like a pig when you are already sweating outside?

otuutti• 4 months ago

Only 1 test subject, but might at least be interesting read: https://blueprint.bryanjohnson.com/blogs/news/sauna-protocol

bilsbie• 4 months ago

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

colordrops2• 4 months 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.

raffraffraff2• 4 months ago

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

davidmurdoch• 4 months ago

Yes. And if you can get it to 102F your body will produce heat shock proteins. Which are good for a whole bunch of reasons, but also can be very bad if you have any tumors, as it makes damaged cells more resistant to apoptosis.

LorenPechtel4• 4 months ago

Yeah, the article is saying core body temperature changes by 2C.

stevenhubertron• 4 months ago

Sample size is tiny fwiw.

moltar• 4 months 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• 4 months ago

Towaway693• 4 months ago

It’s also great for certain mental health issues: spending time naked with a mixed crowd (yes mixed female and male) can be eye opening.

Saunas are a great leveller between humans all living the same experience yet feeling alone in doing so.

euroderf9• 4 months ago

For the record, "mixed crowd" is for people who already know each other or maybe are at some kind of (countryside?) event. Public facilities are segregated by sex, and most private functions with a single sauna will organise separate sessions.

Families will typically sauna all together, altho this system can break down when kids hit puberty.

MaxikCZ• 4 months ago

I heard that we often get cold/flu/sore throat when we get too cold outside, because the inside of our orifices is kept at a certain temperature to kill those bacteria/viruses. When we get too cold, we are unable to kill them fast enough, and get overrun. Staying in 70-100°C air for prolonged time must also heatshock those parts of our bodies, so I guess we kinda sterilize it that way.

At least my 2c why I think its helping

NoLinkToMe• 4 months ago

Also anecdotal evidence, I haven't been sick this whole past 12 months. Any change I made in the past 12 I could've contributed to this. Nothing particular comes to mind but there were lots of changes (e.g. work, home, diet). That's the issue.

You'd have to stop sauna for a while and see if it reverses to strengthen the anecdotal case I guess.

hbarka• 4 months ago

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

cpncrunch• 4 months ago

Its not a storm though.

theptip• 4 months ago

IIUC the operating theory is that a short burst of acute inflammatory stimulus clears out the system to below the prior baseline.

ipnon• 4 months ago

It’s like saying you don’t want to exercise because it induces tachycardia and hypertension. The point is that you are training your body to adapt to overstimulation in a context and dose dependent manner.

ascii0eks844• 4 months ago

Sauna basically is the "hot winter" simulator.

carlosjobim3• 4 months ago

Sauna is the perfect activity to add to most people's everyday routine. It is 30-60 minutes of relaxation for the body and mind, which nicely fill in the slot between dinner and bedtime, instead of TV/Netflix or doom scrolling in the sofa.

shevy-java• 4 months ago

Nordic strong men and strong women.

MrJagil• 4 months ago

I have been searching for benefits associated with hot yoga as well, but the area is very underexplored as far as i can tell.

ekropotin• 4 months ago

Cold showers - good for immune system. Heat expose - good as well. I guess what doesn’t kills us - makes us stronger is true after all.

LorenPechtel4• 4 months ago

Cryotherapy, also.

I'm wondering if what's actually going on is the temperature swings are what's important, not how they come about.

I have also seen both scuba diving and skydiving suggested as beneficial due to the oxygen changes.

Could this perhaps be a form of exercise for the body's regulatory systems?

sexy_seedbox• 4 months ago

Why do Hongkongers (no sauna culture) and Japanese have higher life expectancy than Finns?

bitexploder3• 4 months ago

Because Sauna isn’t a magical, just beneficial?

jogu• 4 months ago

Onsen (hot springs) are very common and popular in Japan. Nowadays, they almost always have sauna as well. In Tokyo there's probably a sauna within ~15 minutes of just about anywhere.

oxag3n• 4 months ago

Back in Eastern Europe I frequently visited public "sauna" with my parents. It included jumping into freezing water after three heat sessions and the only thing you feel is just tingling in your skin. During those years all my respiratory illnesses were very brief and never affected lower areas (like bronchitis). The very first year I've emigrated I've got pneumonia and needed antibiotics twice during the cold season. The doctor told me it's just different viruses and I didn't have immunity for those (which is ridiculous considering globalization and I wasn't in an isolated tribe before).

For my parents though I think it was net health negative as public sauna was always accompanied with a lot of alcohol.

hsuduebc2• 4 months ago

The thing about sauna I love the most is rare moment of absolute clarity after hot/cold cycle. I rarely can think so clearly, even if it's only for ten minutes, than after putting my body to stress by sauna heat.

Weirdly I never saw any explanation.

m463• 4 months ago

I had a water heater go out, and I took cold showers for a while, even after I fixed it. I felt absolutely awake after getting out of the shower. It also didn't fog the bathroom mirrors.

I stopped because one day I took a warm shower and just gave it up. Don't know if taking hot showers was a lack of discipline, or sanity returning.

geekraver• 4 months ago

What about non-Finnish sauna heat? Or do I have to go to Finland?

Finnish sauna heat exposure induces stronger immune cell than cytokine responses

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