Frequent sauna bathing can reduce the risk of dementia
sciencebulletin.org
sciencebulletin.org
Most of the dismissing comments have a few common themes...
1.) They underestimate the prevalence of sauna use in Finnish culture, where the study was conducted. Finland has a population of around 5 million people, but has around 3 million saunas. Sauna access is ubiquitous and not strictly a marker for socioeconomic status.
2.) They disregard the fact that physical activity was adjusted for. In other words, sauna use wasn't simply correlated to overall physical activity in this case.
3.) They assume that because sauna use is correlated with longevity (after variables are adjusted for) that we should expect Finnish folk to live as long as the trees. In actual fact, while sauna use is probably a healthy habit... the Finnish have habits that undermine their health just like any other country.
4.) They forget about the evidence in lower organisms. In flies and worms heat stress (exposing them to a 30 min. heat chamber just one time) has been shown to boost lifespan by up to 15%. This effect was shown mediated by heat shock proteins (hsps), which are very robustly increased in humans during sauna use. I don't know for sure that the Finnish sauna longevity study has anything to do with an effect from HSPs... but it stands to reason! The fact that lifespan extension was demonstrated in two very different lower organisms also means that this effect is highly evolutionarily conserved.
5.) They also tend to forget that humans that have a gene variant in heat shock protein 70 that makes it active all the time have a significant increase chance of living to be a centenarian (at least 100 years old).
For those interested, here's the sauna longevity study in question... http://www.ncbi.nlm.nih.gov/pubmed/25705824
Are they specifically heat related or any temperature stress might do?
I've been using cold water exclusively year round for last few years with occasional show/ice baths in winter time. I'm wondering if I'm missing something by avoiding warm water/saunas.
Re oxidative stress, can you give practical examples of how this is achieved for a person, what physical action creates it? https://en.m.wikipedia.org/wiki/Oxidative_stress suggests it's associated with lots of great harms - brain diseases, heart disease, etc.. How does that pair with longevity in practice?
It doesn't. It pairs with shock proteins.
Another finding that I remember about physical activity being accounted for is the fact that sauna itself contributes to heart fitness, since cardiac activity is increased during sauna. So effectively reducing prevalence of heart problems in people with no pre conditions.
I live in Finland, and I also need to point out that sauna is almost an holistic thing, contributing greatly both to you mental and physical well being.
Does that mean one can have the similar effects by sitting close to a heat source for half an hour some, without the full cost (or exact technique) of being into a sauna?
Do people socialise whilst being in a sauna, or do they rather meditate? Does it differ per person or region? If meditate, has there been cross reference between people who meditate instead of sauna?
Mostly the sauna is a family thing (yes, the whole kernel family of parents and small children may go together to their own sauna, everyone's naked, until the children are close to puberty and men and women of family go separately; public saunas such as those in swimming halls or the traditional public washing facilities are strictly gender-segregated.)
Sauna is perhaps a bit more of a social happening than meditation, although there are some clear aspects of meditation as well. As of old, sauna is a "holy" place; you're not supposed to yell, as the house-elves would not like it. In traditional farms, sauna was were babies were born, and where the dead were washed, so it's a bit of a place of reverence. And it used to be the cleanest and often warmest part of the household.
Source: I used to live in Finland.
Most often this occurs with young university students.
Ok, ok, just kidding -- Finns can talk plenty! But seriously, in Finnish culture sitting silently together is a legitimate form of socializing, unlike some other cultures. Conversation need not be constant.
An interesting documentary to watch is Miesten Vuoro (released as Steam of Life in English, but literally translating to 'men's turn'). It explores sauna culture on one level, men's emotional lives on another level.
And as ptaipale says below, "In sauna one should be like one is in church" -- my terrible translation of a phrase about a certain traditional attitude toward sauna behavior.
Are you joking or is this real, like 4 people might meet up and it wouldn't be uncommon to sit there not speaking?
There's a classic joke about this:
One day two friends, Jukka and Pekka, meet after a long time apart and they go to a sauna in the woods. They drink vodka in silence for a couple of hours. Then Jukka asks: “So Pekka, how have you been doing?” Pekka says nothing, and they continue drinking for another couple of hours. Eventually Jukka asks: “How's the family?”. At that point, Pekka stands up and shouts: “Did we come here to talk, or did we come here to drink?”
(courtesy http://telefinn.blogspot.com.au/2011/09/finnish-jokes-about-...)
After returning from an international travel experience, coming back to the States this was very noticeable culture difference.
I consider it an extremely rude gesture, and not at all courtesy. If you're asking someone how they are, you should do that genuinely, or not at all. While I fully understand how it is being courteous there are different ways to be courteous which don't include asking questions you don't really want answers to. IOW, I find it very fake.
Although I do experience it more here as well, thinking back I remember it occurring at work and in family. I tend to avoid using it.
I sortof feel the same on 'have a good one' except here this does not hurt anyone, and it does not cause misconception. It is merely ending on a positive note. With that being said, a better way of introducing is "hello, pleased to meet you" since it shows dignity, or just "hello, good morning" which is more neutral. All of these are kind and small gestures but not overly or in the sense of inviting too much chit-chat, or invitations to doors which ought to remain closed.
Anyway, no matter how much I dislike it, it won't change. At the same time I don't have to put myself on that level.
Related: http://satwcomic.com/small-talk
Edit: It Looks like a sauna is dry heat, a steam room is obviously moist heat. The sauna is typically kept hotter- 160-200 deg F, while the steam room is usually 110-115 deg F.
Best saunas are quite moist and not too hot, but the amount of moisture in air is controlled by the bathers. Sometimes this ends up in a competition (who can stand the wettest steam) but that's actually slightly bad manners.
For perfect results, I add a little beer to the water I throw on rocks (this is a matter of taste, some say that's not proper; in any case, things like menthol or eucalyptus don't really belong in Finnish sauna steam).
As to the positive health impacts, I'm completely agnostic. Or perhaps I think that it's more that healthy people can go often to sauna, not that going often would make you healthier.
In Dutch saunas (many of which have a sauna room called "Finnish sauna", which tend to be the hottest and driest of all), löyly is not standard, but only done in one sauna room at specific times, and controlled by the sauna personnel. (Dutch saunas tend to be commercially exploited complexes with multiple types of sauna, a steam room, masseurs, etc.) The sudden increase in moisture does help make you sweat more, and a lot of people appreciate that (but not everybody). And it's definitely often with eucalyptus or other fancy oils.
does anyone know if there is a temperature threshold for inclusion in the study? Saunas in the United States (only been in a few, like at the 24-hour fitness club) are, to me, tepid--feels like i'm in a sauna in which someone put out the fire several hours ago.
Russian saunas are are much, much hotter and i rarely see foreigners in them which suggests they are too hot for their tastes (though probably not for Turks or Finns). Saunas in villages or small cities in Russia and Belarus, which tend to adhere more to traditional recipes, are so hot (a little above 90 C, i've always been told is what they aim for) i can't tolerate them for more than a few minutes (and even the locals usually wear felt beanies while in there).
edit: and your link is broken
There is no such thing as a standalone sauna that's not also a pickup spot, though would love to be proven wrong.
Archimedes Banya (www.banyasf.com/) is my favorite. They have a real Finnish sauna that gets up to 100 C (or over) along with a pool for cooling off that is less than 10 C. They also have two Russian baths and a Turkish bath (steam room). To get that real Finnish/Russian experience, you can even bring your own alcohol. Clothing is optional on one half and required on the other.
There are others in SF, but I haven't been to them.
In analysis adjusted for age, alcohol consumption, body mass index, systolic blood pressure, smoking status, Type 2 diabetes, previous myocardial infarction, resting heart rate and serum low-density lipoprotein cholesterol, compared with men with only 1 sauna bathing session per week, the HR for dementia was 0.78 (95% CI: 0.57–1.06) for 2–3 sauna bathing sessions per week and 0.34 (95% CI: 0.16–0.71) for 4–7 sauna bathing sessions per week. The corresponding HRs for Alzheimer's disease were 0.80 (95% CI: 0.53–1.20) and 0.35 (95% CI: 0.14–0.90).
http://m.ageing.oxfordjournals.org/content/early/2016/12/07/...
It's amazing if Finland has solved poverty to the level that every household can afford to set aside the space for a sauna and costs of running it.
In the UK heat poverty is a widespread problem due to the costs of heating fuels. Presumably saunas are being run from geothermal sources to make it cheap enough??
I'm assuming saunas are cupboard sized, is that accurate or are all these homes dedicating a full room of space?
Municipal facilities (swimming halls with saunas etc) are charged, probably about 4 euros per visit, with discounts for students and elderly.
The saunas people have in their homes these days are typically electric. Electricity prices are roughly the same, perhaps a bit less than UK - an hour of sauna with 4kw stove would probably cost around 0.5 euros in electricity. Some apartment blocks have shared saunas you can book for free, some have small saunas in each apartment. In detached houses you typically get a bit larger saunas.
In general access to saunas is widely available for everyone regardless of socioeconomic status, and there is less economic inequality in general compared to the UK.
Heating is a separate topic but I'll reply briefly - majority of housing in Finland is heated with district heating, rather than individual gas boilers in each house, like in the UK.
https://en.wikipedia.org/wiki/District_heating#Finland
As a result, heating tends to be cheaper for consumers compared to the UK. Also, Finnish housing tends to be much better insulated than housing in the UK (because of colder winters).
Outside cities, where population is sparse, people heat their houses with electricity/wood/oil/geothermal - with many new builds now opting for geothermal.
See http://energia.fi/files/799/Lu_Kostama_Mikkeli.pdf slide 10.
And saunas are heated with electricity in towns, although a few old public facilities still run on wood stoves, as well as private saunas of those who like the "pure" feeling (such as myself).
Couple that with the higher housing costs associated with far higher population density (16 per km^2 in Finland vs. 255 per km^2 in the UK) and it seems less weird.
I would imagine that he cost of the heating fuels is pretty much the same all over Europe. I think the difference is that in the Nordic countries people seem to insulate their houses better, like using double or even triple glasses in windows to reduce heat waste.
UK has 3.16 million hectares of woodland[1], Finland has 23 million hectares[2] of forest. UK population is 65 million, Finland has 5 million. [Wikipedia]
With 7 times more trees potentially providing fuel for 1/13th as many people, shouldn't it work out noticably cheaper?
Gas, oil, electricity, district heating or geothermal heat are used. Prices will be roughly similar, where the supply exists.
In the context of "It's amazing if Finland has solved poverty to the level that every household can afford to set aside the space for a sauna and costs of running it.", and rural areas tend to be poorer than city areas, discussing wood as fuel for said saunas seems relevant.
If you live in an apartment building, not every unit has a sauna--there is one shared across several units. If you live in a detached house, having a small sauna doesn't take up much space, and since it's so small and only used for an hour a day (if that), it's cheap to heat.
> In the UK heat poverty is a widespread problem due to the costs of heating fuels.
Based on my experiences in the UK, it's not heating fuel costs that's the problem, it's the sheer ubiquity of poorly insulated and air-sealed brick (and in Scotland, stone) houses with leaky single-pane sash windows.
Since this crappy cold weather hit I've found myself going to the gym nonstop just to dip in the jacuzzi... I don't know why most apartments in the PNW seem to not have one, maybe people up here don't like to swim as much as people in warmer climates?
Sauna is definitely anecdotally good for many skin conditions including fungal infections (my cite is only my own life).
In the very first sentence a causal relationship is claimed ("Frequent sauna bathing can reduce the risk of dementia"). Yet the whole article doesn't live up to that claim, because it is very clear that the study purely relies on observational data and thus may very well just have found a confounder. However it doesn't even bother to mention or discuss that limitation.
Usually all the basic concerns have been accounted for in the actual study.
Whether an article in the mainstream press conveys that or not, is not important, since the article is just supposed to give a summary of the findings.
It's seldom an issue of "those stupid PhDs and experts in their field, they didn't think of a confounder a random internet person can come up with in 5 seconds".
Whoever wants to delve in can read the actual reports.
And whoever wants to start the same practice (e.g. sauna here) would be foolish to do it based on one article anyway, they should consult with their doctor, and/or wait until a fuller consensus has been reached after several meta-studies (which can take decades).
Claiming a causal relationship is an incorrect summary if the study did not show this. This is a very serious problem. If the particular study did in fact show good evidence of causality, that's worth specific highlighting because it's not that common.
The parent is not saying they've thought of some obvious confounder that the study authors didn't. They've emphasized the importance of unknown unknowns and correlation vs causation.
Raising the standard of science journalism is a noble goal, if you ask me. In this case, the authors are not making as strong a claim as the summary does.
No. It's an observational study. If they'd account for the basic concerns they'd do an RCT. Yes, that's more work and takes longer.
> It's seldom an issue of "those stupid PhDs and experts in their field, they didn't think of a confounder a random internet person can come up with in 5 seconds".
No, you don't understand the problem. Confounders everyone can come up with can be controlled for (although it gets complicated the more you consider). But the major problem are unknown confounders. You can't control for things you don't know.
In health sciences, a lot of good work starts as well-controlled observational science. In fact, for a question like "does sauna use lead to a reduced risk of dementia over a human lifetime?", pretty much the only way you're ever getting the funding to do an "RCT" is to start with lots of observational evidence.
Often. Yes. But I often go try to find the original publications when a study interests me, and I have yet to, once, find one where the causal claims made in the reporting article are actually supported by the research. Often the original paper explicitly mentions the fact that the claimed causal relationship can't be inferred.
The claim here isn't that the science is bad. No one's saying the PhDs are stupid (there may be an argument there, but that's not what anyone here is saying). The complaint is that the science reporting is terrible.
And it is.
> And whoever wants to start the same practice (e.g. sauna here) would be foolish to do it based on one article anyway, they should consult with their doctor
You are suffering under a severe delusion if you think the average doctor has the interest or competence to provide useful advice on this sort of issue. The average doctor will not have read any relevant studies, and has no interest in being informed about them, and I can say with some confidence that having a medical degree does not give him a magical ability to judge the usefulness of a practice without consulting any evidence.
Science is great, but science reporting is terrible, and for that matter unreasoned faith in the academic establishment is anathema to real science.
Fair enough ... but there could be simple and nuanced elements that they didn't or couldn't measure.
For example: maybe Sauna dwellers are far more socially active than others? Social interaction is maybe they driver of longevity, the sauna may simply be a part of that process.
Anyhow, just a crude example ... but I'd suggest it's very hard for researchers to rule out most such things.
No, I don't think so: http://www.economist.com/news/leaders/21588069-scientific-re...
But if the Finns really sauna this much more often than anyone else, then there should also be a noticeable difference in dementia between Finnish people and anyone else.
I'm going to go out on a limb and say the sauna cohort and the Bikram cohort are two extremely different sets of individuals with lots of different behaviors, so if the same effect was found in regular Bikram yogis a lot of variables might be able to be eliminated.
Installing one isn't too difficult - if you have a garden, you can get outside kits which are generally as simple to build as sheds, or indoors kits that you'd put in a bathroom - probably when doing renovation anyway. I recommend ones from Harvia - I bought a medium sized one (fits 4 people) for about £1600 in the UK, and it took me and a couple of guys less than a day to put up.
Here are some pics - I built it as a part of a loft conversion and ended up tiling the outside so it looks like a part of the bathroom. Normally these prefab kits look like a softwood cladded mini-room from both inside and outside
The stove is usually 4kw-8kw so you'll need to add appropriate wiring and fuse/breaker.
If anyone is contemplating building one, feel free to ask me for advice.
The starting temperature of World Sauna Championships was 110° C, with water/steam added every 30 seconds. The competition ended up killing a person, tho.
The wood in the sauna does get hot: that's why you either sit on a piece of cloth (more popular these days) or put cool water on your seat to cool it down so your butt doesn't burn. However, wood in saunas is generally carefully selected as some varieties feel cooler than others (and you never want to use a wood that will produce sap drips for your benches! ouch!!). There are almost no metal components to touch in a sauna because those hurt -- some people use copper buckets for water but then you're filling it with cool water intermittently.
Take off metal necklaces and earrings before saunaing, in general. Don't know about piercings (someone else can say). You can cook/burn yourself in a sauna but that is usually related to drug and alcohol use (as in the famous World Sauna Championship death: https://www.theguardian.com/world/2010/aug/08/sauna-champion...)
No, you get in the water below 10°C. The 80° (or 90°C, as I often see claimed on Finnish saunas in Netherland) is the air. Extremely dry air, where your sweat evaporates almost immediately. Until someone pours on the löyly.
I'm thinking about putting one outside. May I ask you some questions?
So good news everbody: If you use a sauna seven times a week, there's a chance you could become immortal.
[0] http://www.reuters.com/article/us-heart-health-saunas-idUSKB...
[1] http://ageing.oxfordjournals.org/content/early/2016/12/07/ag...
I have studied statistics, and I understand that correlation does not imply causation. However, if you're going to allege that a professional scientific statistician failed to even consider the most trivial and obvious of non-causative correlations, then you're being insulting.
And it's fine to insult scientists. They're not special snowflakes. Do it, if they have a track record of lies, or deceit, or carelessness, or stupidity. But be aware when you're doing it, and why. Don't just blithely say "Hey guys, have we considered the possibility that these scientists are either drooling idiots or evil liars?" That's uncharitable to an extreme.
And yes, I've read it. They are not, as OP suggested, drooling idiots or evil liars.
It's concentrated uncomfortable sitting around combined with the occasional panic. If you're buoy racing, it's on the rail, over the top and grind for 3-5 seconds and on the rail.
You can buy prefab kits (so the moisture barrier is built in and the benches are pre-assembled) from companies like Finnleo, or you can buy a stove alone from tons of places. Just make sure you're buying a stove that is truly meant for a sauna (throwing water/making steam) instead of a heater for an infrared room (different!).
He just asked that you don't be "shallow", or in your own words, "snarky" about it, as it always makes discussions worse and degrades HN overall.