[bluGill]

The most important thing you didn't measure: does this affect long term health in the same way exercise it known to. That is can I put a TV in my sauna and watch that for an hour every day instead of getting out and exercising - yet get the same better long term health outcomes?

My current guess is no. That is this improves a marker for good health without improving health. However this is a guess by someone who isn't in the medical field and so could be wrong.

[nsbk]

I recently listened to a podcast about the benefits of sauna or deliberate heat exposure and the gist is that if you get your core temperature at about 39 degrees celsius your cardiovascular system is working comparably hard to light exercise.

My take is that your heart and lungs are working out, even if your body is not. Do you get the same benefits as going for a run or bike ride for a comparable amount of time? no, since your limbs don't get fit, but your heart and lungs do.

[shmel]

Not saying you are wrong, but I'd like to see some evidence on that. Just because your heart is pumping faster doesn't mean your cardio fitness is getting better. Otherwise we could all just snort cocaine and skip the gym. Alcohol does that too, anyone with a fitness tracker can check that.

[asdfman123]

Athletes already know the answer from years of cultural knowledge, research, and firsthand experience. No, it doesn't make your cardio fitness meaningfully better. If you did sauna training for years and then tried to ramp up for a marathon, you'd be hopelessly out of shape.

Endurance athletes obsessively track VO2 max, basically your body's ability to consume oxygen during workouts, and it certainly doesn't improve with sauna training.

It's like asking "if you only did puzzles, would you be smarter?" Well, in a way, yes, but if you actually want to compete with someone with a good education you have to read.

Same with physical exercise. It puts a lot of different stresses on your body that saunas don't. The question isn't "do saunas make you physically fit," because they don't. The question is "for people who don't want to exercise, does sauna training alone meaningfully extend your healthspan?" I'm guessing the answer is "a little but not enough," but I'm not sure.

[monkpit]

You’ve honed in specifically on VO2 but what about cardio health in general? Like light treadmill, not like a demanding marathon.

[asdfman123]

Cardio of course is short for "cardiovascular system," which consists of a whole lot of moving parts. Saunas improve some parts of it but certainly not all of it.

Will fixing up your radiator fix your car? Maybe, if the radiator was the problem, but there's a lot of other stuff inside a car to work on, too.

Your body evolved under the expectation that it would be stressed in numerous different ways, but those stressors can all be avoided in the modern era. If you want to most reliably recreate those stresses you need to do cardio and resistance training.

[barnabyjones]

Without exercise, you won't burn ATP and thus won't increase mitochondrial count.

[nradov]

A light treadmill session won't do much to improve your cardiovascular system health either. I mean it's better than nothing but don't expect too much.

[xtracto]

Moreover, I'm from a very hot and humid tropical region. Its normal to ne 40°C with 80% humidity there. And you dont see people having better health or longevity (Yucatan peninsula) .

[smileysteve]

40° internal body temperature is not the same as 40° weather.

Yucatan is not the same as Dubai in Summer.

Your body is under heat shock trying to keep up in a Sauna (that isn't considered warm until 60°). Versus a healthy body CAN keep up in 40°.

The Yucatan equivalent of a Sauna is more like doing hard labor on a roof on a sunny day with no breeze.

[Tor3]

Right, it's just that a sauna at 60 degrees is not warm, it's cold. Take a shower, go into the sauna at 60 degrees C, and it'll feel cold. Nothing happens in a sauna until you're getting near 80, and it's much better if you go somewhat higher (90 or more for active users). 60 is when a sauna will be closed off in public baths because there's a technical problem somewhere.

[actionfromafar]

But that would be like exercise all the time which may not be optimal. (Not saying the theory holds that sauna equals exercise, but if it does, sauna all the time may not be great. Plus, there may be other confounding factors with living in various locations.)

[Insanity]

The great but not super healthy Mexican diet might offset the potential heat exposure benefits! Although I’m basing that on the diet of my Monterrey-based in-laws, not sure how different Yucatan is.

[xtracto]

LOL, Monterrey diet is healthy compared to the diet in the Yucatan peninsula.

Tamales, Cochinita (roasted pork with herbs), salbutes, trancas. Everything of course cooked in Lard. With CocaCola on the side.

So yeah, that's a strong point.

[cpursley]

Lard is fine as is pork, it’s the sugar and carbs.

[mminer237]

Edit: I posted this accidentally when editing without noticing. Hypertrophy isn't necessarily a bad thing. I thought I was discarding the comment cuz I realized I was out of my depth. whoops

Please ignore my comment, though I will leave it to make the below comments less confusing.

Original: You don't want to "work out" your heart though. Cardiac hypertrophy is a bad thing.

The benefit of exercise is that your muscles become more oxygen-efficient. Your heart endures some stress now, so that it can work less in the future.

[kiritanpo]

Cardiac hypertrophy is not necessarily a bad thing, it can be the result of positive adaptation, such as exercising.

Eccentric hypertrophy (athlete's heart) is the positive adaptation resulting from training the heart. The heart has a lower resting rate and is more efficient at pumping blood. It returns to normal size if training stops.

You'll never reach a state of hypertrophic cardiomyopathy (the bad kind of hypertrophy) with exercise. Its cause is usually genetic.

[kazga]

Not true. You can't really train your muscles to use less oxygen for the same energy output (what "oxygen-efficiency" would imply). You rather increase their capacity to take up oxygen from the blood and burn it. They will use more oxygen to output more energy.

That additional oxygen needs to come from somewhere. Endurance training at the same time trains the heart to deliver more oxygen to the periphery; the primary mechanism is increased cardiac stroke volume.

[bluGill]

You kind of can - the muscles can use aerobic or anaerobic processes. When you develop brute strength you are training those anaerobic processes. That isn't what OP was talking about, and overall it is much less energy efficient, but it does produce a large burst of energy when needed and you can train your muscles that way.

[gf000]

I would assume that another factor is that the technique for a given exercise on the other hand can be improved, and that can help with decreasing the necessary energy - would that be a correct statement? And as a follow up, depending on activity type this may or may not be significant?

[frocodillo]

Yes, definitely. Technique is partly about efficient mechanical movement, sending the various parts of your body in the right direction(s) and not waste effort on movement that doesn’t contribute to propelling you forwards. But for endurance sports, it’s really about minimizing energy cost at a given speed. To use running as an example, you can improve biomechanical efficiency through better timing, correct loading of tendons, tendon stiffness, elastic energy use, and more.

[SJMG]

This is terribly uniformed. Do not listen to this.

Cardiac hypertrophy isn't a "bad thing". This is completely contextual. What you don't want, for example, is pathological hypertrophy from things like hypertension, or exclusive left ventricular hypertrophy without associated increase in chamber size.

The heart is very complex. You 100% should exercise it.

[adrianN]

Wikipedia says Athlete's heart is benign: https://en.wikipedia.org/wiki/Athletic_heart_syndrome

[groundzeros2015]

This is why I hate health science. Informed people can have the same information and come to opposite conclusions. The entire field is made up of contradictory explanations and principles, to the extent that it’s unknowable what’s true or not.

[robrenaud]

The flat earthers are why I hate astronomy.

Afaict, the grand parent poster is just very wrong. You do want to cause acute stresses to your heart (cardiovascular exercise) to get it work better.

[groundzeros2015]

It’s not really about this particular claim. It’s that I can read a comment that has a reasonable chain of logic and I don’t know if it’s true. This topic is just not easily studied and theories are hard to falsify.

[groundzeros2015]

Claims about flat earth are falsifiable with at-home experiment.

[rhyperior]

That seems… misguided.

Sources?

[jagged-chisel]

Your heart is also a muscle.

[PaulDavisThe1st]

... about the size of your fist. Keep loving, keep fighting.

(attributed to Bertolt Brecht)

[bluecalm]

For endurance training the main benefit of heat training is raising blood volume. Lungs are not a limiter. Developing stroke volume I imagine requires much higher intensity but that's just a wild guess based on my limited understanding of physiology.

If heat training is better than another interval session remains to be seen but it seems a lot of smart people believe it's worth it nowadays.

[PaulDavisThe1st]

and specifically, to be clear, plasma volume.

[pegasus]

Since you mention the TV, it seems there's a big factor missing in both the article and the discussion here. Namely, that sauna time is for many people the only time they ever take to be in silence, without the countless distractions otherwise bombarding our nervous systems. I.e. it's basically a form of informal meditation, which is known to have a lot of benefic impacts on body and mind. So maybe skip the TV part?...

[willnz]

I recently got an outdoor sauna at home, and that's definitely a key benefit ...sitting in silence without any devices, no smart phones, watches or music for at least 15-20 minutes.

[kyriakosel]

Agreed - one is muscular/metabolic demand, the other (sauna) is thermoregulation.

Agreed on the long-term effect too: doing a study on long term health is a completely different story

[nyjah]

Zero shot you'd make it an hour in a proper sauna for an hour. People have this idea that saunas are always enjoyable. I sauna daily, and its nice up to a point. For me thats like 10-12mins in. From then on, its tough.

[tuukkah]

When it doesn't feel enjoyable anymore, you're supposed to get out of the sauna and cool down - preferably in a lake. Then repeat as many times as you like.

[Tor3]

Yep. A problem with public saunas (outside Finland, at least) is that they lower the temperature (to, say below 80) in the misguided belief that this will make it easier for more people to stay longer inside.. which is the wrong way to use a sauna. A sauna should be hot enough that you'll go out when it starts feeling too hot (or hard), not so cold that you'll go outside when you're getting bored. With a hot sauna small children can leave after one or two minutes, some people leave after five, others after ten, and in any case go outside and cool down with a showre (or a lake..), then go back in.

[iammjm]

I go for 15 min sessions at 90 Celsius and the first 10 mins are ok, the last 5 are tough, like I have to control my breath to hang in there

[httpsterio]

Huh what? I can easily sit in a sauna for an hour without breaks as long as it has some type of ventilation.

Smoke saunas a bit less, electric or wood stove saunas no issue. It's nice to take a breather once in a while but I'd honestly have no issues sitting in a 80-90 deg sauna for an hour as long as I have enough to drink with me.

One time I sat in the sauna for six hours with a few breaks between with a group of friends shooting the shit. I had a headache the next morning but I blame it on the Jallu and not the sauna.

[Tor3]

At which temperature?

[httpsterio]

The one event where we say and drank, it was about 90 deg celcius and lots of water on the stove (löyly).

[bluGill]

I generally make it about 30 seconds in a sauna (I rarely even bother trying when I have access). Should I tough it out for 10-12 like you? Should you be toughing it out for the full hour I suggested (a random time I pulled out of my head)? Or is this all nonsense and I'm just fine ignoring the whole thing?

[Tor3]

Don't "tough it out" in a sauna. Stay until it feels uncomfortable, or, if you're not sure, keep track of your heart rate and get out if it increases too much. You'll get used to the sauna after frequenting it for some time, which usually results in being able to stay longer before it feels uncomfortable. Your ability to sweat will improve, for example, including being able to sweat on body parts where you may initially be unable to (it took a long time before my wife's calves "learned" to sweat, for example).

[MyHonestOpinon]

IMHO. 10-20 mins is good enough. I wouldn't try to stay for an hour.

If 10mins feels too much, do less.

[theshrike79]

30 seconds? What kind of torture room of a sauna are you going in?

[marssaxman]

Heat tolerance varies. For some of us, all saunas feel like torture rooms!

[trklausss]

You are clearly not Finn (/s)

[nyjah]

lol, this is true. Wish I could tolerate it longer like a proper Finn. I’ll go 25 mins occasionally but mostly I do 15 mins, break, another 5-10 mins..

[jampekka]

Finns don't do it that long. It's typically 5-15 minutes per sitting, with 2-4 sittings per session.

[nyjah]

My answer was sarcastic back, fwiw, I follow the 'proper' finnish ritual or similar...

[lfuller]

This feels like a false dichotomy. Even if sauna doesn't impact long term health in a way that can replace exercise, that doesn't mean that it doesn't improve health.

[HelloMcFly]

> That is this improves a marker for good health without improving health

There is a substantial body of existing research to peruse about the impact of regular sauna use on health outcomes, much of it from Finland given the prevalence of sauna usage there allowing for larger sample sizes. It's a body of evidence rather than one knock-out experimental design.

[gjulianm]

Much of that body of evidence relies on self-reported and self-assigned sauna usage rather than actual randomized trials, and also the papers show massive risk reductions that do not really fit with the country-level data (e.g., if saunas are that good for cardiovascular health and finns use them that much, why do they have similar rates of CV disease as neighboring countries that don't use that much sauna?)

[HelloMcFly]

Much of it is, sure, but certainly not all of it! On your comparison to Sweden, be cautious! Finns generally have a higher risk and incidence of cardiovascular disease compared to native Swedes - in fact, they have some of the highest risk in the world!

Research from Earric Lee and/or Jari Laukkanen from this past decade will have clinical trials with controlled groups rather than just long-term population tracking. There are within-Finland studies comparing high-risk Finns who use the sauna 4 to 7 times a week against high-risk Finns who use it only once a week, showing a clear effect (https://pubmed.ncbi.nlm.nih.gov/25705824/). Here is a non-randomized experiment showing a dose-response (https://pubmed.ncbi.nlm.nih.gov/29048215/).

Those are just indications of information available. I would also argue that while of course randomized experiments are ideal, it is a mistake to dismiss all other forms of evidence so readily, especially with such preponderance of it.

[gjulianm]

The first study shows a 0.37 hazard ratio for frequent sauna use. That’s better than a lot of the HRs reported for physical activity. It’s even better than not smoking. It just doesn’t really fit.

Also, the fact that there are practically no sauna related studies outside of Nordic populations is suspicious too. I bet that with those hazards ratios a lot of people have tried to study the effects more, it’s suspicious there’s practically nothing out there.

[HelloMcFly]

There's more research for you to explore if you're interested, but you sound more closed than curious if I'm honest. Maybe looking more into it will change your mind, maybe not!

[gjulianm]

I explored quite a bit because I was curious to see how it was possible that sauna had these great effects and why no one used it outside of Finland. But to this point I haven’t seen anything that really supports the idea that sauna is such a massive health protector as claimed. It’s probably beneficial, yes, but the real benefits are probably far lower than claimed.

[jjallen]

My current guess is that you get much or most of the benefits, but not all (by both value and number). If you look at the actual changes in the body during both of these activities, most are the same as exercise, but not all.

For example: body temp increases, heart rate increases, and we sweat. But the muscles aren't "engaged", consuming stuff (glycogen, etc.) while doing sauna.

There could also be sauna benefits that exercise does not impart, or is less likely to do so: sweating greater than exercise could lead to excess excretion of plastics, carcinogens, etc.

Running in mild/cold temps we do little sweating (unless long duration exercise), whereas every darn sauna at sufficiently high temps we are going to be sweating.

[ricardobayes]

My take is probably too nuanced here, but the reality is that we don't know. People living in areas with longevity (blue zones), didn't really excercise (as in sports) or take multivitamins. For all we know, it might even come out that regular, gym-style excercise is even worse for longevity.

Nordic people tend to live a long life even though they historically didn't have access to fresh vegetables or fruit and brutal winters (and darkness) prohibited excercise.

ps. I'm not arguing that excercise is unhealthy, it's just that its contribution to eventual longevity, is currently unknown. Whereas anectodal evidence of saunas (being around longer than "excercise"), seems to work.

[somebodythere]

There is some evidence suggesting that "blue zones" are largely about pension fraud. https://fortune.com/europe/2024/12/14/are-blue-zones-myth-ex...

[jeffbee]

You're saying that crime leads to longevity? Big if true.

[taeric]

I think the claim is more that if you provide financial support for X without solid record keeping to verify X, expect that you will get more self reported people in that description.

Put differently, relying on self reporting for any sort of status from people is just not a reliable methodology.

[yxhuvud]

No, he is saying bad record keeping means misreporting identity has a bigger chance of happening.

[projektfu]

Fraud leads to people officially living beyond their natural death, yes.

[RankingMember]

> I'm not arguing that excercise is unhealthy, it's just that its contribution to eventual longevity, is currently unknown

I see numerous studies indicating that exercise contributes directly to eventual longevity, e.g.:

https://www.ama-assn.org/public-health/prevention-wellness/m...

https://www.acc.org/latest-in-cardiology/articles/2025/07/02...

https://pmc.ncbi.nlm.nih.gov/articles/PMC3395188/

[ricardobayes]

Thank you for the resources.

I do wonder what the correlation is: is it only because of excercise, or at least partially also due to the fact those who can set aside time and effort (and often, money) to exercise, have a "better" life than those who don't?

For example, high life expectancy in Madrid, and Switzerland are often attributed to having broad access to great healthcare and stress-free lifestyle(both), despite living a relatively "unhealthy" lifestyle, at least in Madrid. Eating fried food everyday, little exercize among elderly (at least if you don't count walking to the bar). Those 85 year+ Madrileños probably had their last formal exercise when they had to do their military service back in the day.

As in the case of top athletes, in your second article, is their longevity due to heavy exercise, or kind of, "despite it", and at least partially due to their accumulated wealth, health-conscious mindset plus the ability to afford a stress-free life?

[standardly]

The equation is not simply "exercise" -> "live longer" via some unknown correlation.

Exercise increases cardiovascular health, mental well-being, etc. It should be pretty obvious that someone with less risk of heart failure will live longer on average (considering the #1 cause of death in the US...) I don't think you need to factor for every possible life circumstance to deduce that known-healthy activities improve longevity

[brushfoot]

> People living in areas with longevity (blue zones), didn't really excercise (as in sports)

Not exercising as in sports and not exercising, period, are very different. If you look at the American blue zone, those people are certainly exercising; daily nature walks are baked into their theology.

[trklausss]

For all we know, there is a link between cardiac/circulatory problems and arteriosclerosis (that is, loss of elasticity of the vessels).

So it could be that exercise helps keep this elasticity, the same way maybe sauna does? Also antioxidants from vegetables etc.

So it could be that it is a _factor_, but definitely needs way more study.

I am also not in the medical field, but I think arteriosclerosis is a well known link for cardiovascular disease.

[bluGill]

Problem is sauna use and genetic factors corrolate too strongly to make any conclusion to the broader population. If you live in/near Finland you likely sauna often, as have all your ancestors for thousands of years. If you don't live there both are false. Thus we can't know if Sauna is helpful for the general population who isn't of a Finish background.

[shevy-java]

Japan has a +4 years lead of life expectancy over Finland; Norway almost +3 years on Finland. I am not saying this is conclusive per se, but to me the sauna-people-live-forever is not backed up by the data. I would instead reason that, e. g. weight correlates a lot more here.

[smileysteve]

Your comparison reads to suggest that Japan doesn't have Onsen culture or that sauna does not exist in Norway.

That's to say, many cultures from around the globe have developed similar activities that heat the body.

[Tor3]

Saunas are common in Norway, even if not to the same degree as in Finland. The reason Finland has had a lower life expectancy than Norway is believed to be due to the difference in diet (cardivascular issues). Note that the diet in Finland has changed quite a lot over the last decades and these differences will presumably level out, statistically.

[bluGill]

Nobody is claiming they live forever. The claim is sauna use increases lifespan. There are other factors than just sauna use in lifespan though. The question is would the Japanese live even longer if they were using a sauna?

[gonzalohm]

A lot of Mediterranean countries also have high life expectancy and are the opposite of a sauna culture.

[kyriakosel]

Cyprus summers are like 45C and its almost like a sauna :)

[GordonS]

Maybe eating a lot of fish, rather than meat, has an impact too.

[bwestergard]

The "blue-zone" studies are flawed, so we shouldn't infer too much from lifestyle generalizations about people in them.

https://www.science.org/content/article/do-blue-zones-suppos...

[idiotsecant]

Saunas have not been around longer than exercise.

[z3t4]

I think that if you have one hour or more of free time and live in an area where you have easy access to a sauna, that would result in significant better health on it's own. Even if you choose to not use the sauna.

[testing22321]

I don’t think the TV in the sauna will have long term health outcomes.

[Filligree]

It will certainly affect the health of the TV.

[sonink]

I looked into Saunas in detail sometime back as a replacement/complement to exercise. There is a lot of research out there which says Saunas are as beneficial - but at the end of it I reached a similar conclusion - exercise is just better understood, so no point experimenting when something can go wrong.

[havella]

This question is dead from the beginning. Exercise is good for the heart, the muscles, metabolism. You do need muscle contractions above certain level of intensity and duration for this to happen.

[Jtarii]

A sauna will do nothing for muscular-skeletal health.

[derektank]

That seems like a very strong statement. Isn’t there evidence that Heat Shock Proteins are produced in response to time in the sauna, which have beneficial effects on muscle growth and repair?

[Jtarii]

>which have beneficial effects on muscle growth and repair?

Repair from what?

[derektank]

Mechanical stress, i.e. exercise

[iso1631]

If you're watching TV in a sauna you haven't turned the sauna on.

[tester756]

One hour in sauna? :O

[bluGill]

A random time I pulled out of my head. If this is real the next question is what is the optimal time. (also temperature and humidity levels)

[jmdeon]

I'm being slightly snarky, but good luck watching a TV if you're doing an intense/valuable sauna session.

When I'm in my dry sauna and really pushing myself with the heat and steam off the hot rocks, I basically have to mediate to stay in beyond 15 minutes because every part of my mind starts telling me to get out and cool down.

[throwaway-blaze]

Even more likely is those using saunas and tracking metrics with wearables are self-selected to be healthier/more active/etc. Correlation and causation...