
Association Between Sauna Bathing and All-Cause Mortality Events - mkempe
http://archinte.jamanetwork.com/article.aspx?articleid=2130724
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bemmu
In Finland going to a sauna is often a social activity. You catch up with your
best friends in a Friday sauna session. If you use the sauna a lot, maybe it
means you have more friends?

There's apparently a connection between social integration and health:
[http://www.ncbi.nlm.nih.gov/pubmed/23681602](http://www.ncbi.nlm.nih.gov/pubmed/23681602)

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maj0rhn
Another uncontrolled-for possibly contaminating factor. There are a host of
diseases that make people heat intolerant. Multiple sclerosis (big in Finland)
and heart failure are two of them.

People who are relatively intolerant of heat will tend to avoid saunas, thus
biasing the outcome in favor of positive health outcomes for people who are
able to tolerate the heat.

So they would have had to do a very careful assessment of these people at the
time of enrollment in the study.

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mkempe
It's based on a 30-year long longitudinal study of Finnish men, not a
miniature people-in-the-sauna "study".

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eloff
Good, I live in a Sauna, 8 degrees north of the equator. That bodes well for
my health :)

Joking aside, this study seems unlikely to have actually discovered a real
effect, rather than just a group of people with lower risk and higher sauna
usage in common. (Wealthy people?)

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pacaro
Given that the study was conducted in Finland, it's unlikely that wealth is a
confounding factor in sauna usage.

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eloff
The effect was only noticeable with sauna usage 4-7 times a week, more than
wealth that implies free time, which implies lower stress (a risk factor) and,
to a degree, wealth.

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maj0rhn
As always, correlation does not equal causation.

According to the abstract, the effect was significant only at a "dose" of 4 to
7 sauna visits per week in the 20 years of follow-up.

Now, I don't know much about the availability of saunas in Finland, but one
must ask: what kind of person can financially afford, or make time for, 4 to 7
sauna visits per week? Even with the statistical adjustment for traditional
cardiovascular risk factors, I seriously doubt that the people who use saunas
frequently have the same income levels, attention to health, and all sorts of
other habits as the people who never use saunas.

So I would put this study on the heap of interesting correlations that
ultimately mean nothing.

BTW, they should look at the development of Alzheimer disease. There is
suspicion that high body temperatures (e.g. with fever) can incite the changes
in protein conformation that are thought to be essential in the establishment
and progression of the disease. So, if sauna users stay a little too long, and
get a little bit hyperthermic, they may be setting themselves up for Alzheimer
disease. That would be a bummer.

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woah
Weird train of thought about the supposed scarceness of saunas. My gym in SF
has a sauna. Many people use it every time they work out. You can only stay in
there for like 10 minutes. Not a huge time investment. Are you telling me that
only the very wealthy can afford an $80 monthly gym membership?

Some apartment buildings in Berlin I visited had saunas built in (and these
were not luxury buildings).

My understanding is that saunas are even more prevalent in Scandinavia. You
should rethink your reasoning.

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maj0rhn
$80 per month is a lot of money for most people. It's like buying a new pair
of running shoes every month. Quite a luxury. This in itself separates groups
of people. Reasoning stands.

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hammerandtongs
"""saunas are even more prevalent in Scandinavia. You should rethink your
reasoning."""

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maj0rhn
The cost of access to saunas is not zero in money, and not zero in time. This
in itself creates differences between groups, which is why randomized trials
are far superior to case-control or observational studies. This is so well
established in medicine that there is no cause to rethink the reasoning.

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mkempe
Based on your comments I gather you have never been in Finland. So you know
close to nothing about social mores and structures in that country. Your
comments are noise, not even wrong.

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jhou2
The title is a bit misleading. The abstract states that "significant inverse
associations were also observed for fatal CHDs and fatal CVDs (P for trend
≤.03) but not for all-cause mortality events." So going to a sauna 4-7 times a
week for these middle-aged Finnish men decreased their chance of dying from a
heart attack. But they still might die from something else at the same or
somewhat increased rate. I'd argue that the raised heat and humidity in the
sauna might have caused an increased workout for the heart. "Shocking" the
heart like this almost every day to every other day of the week for twenty
years made them more able to survive fatal CHDs and CVDs.

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JoeAltmaier
As always, there's trouble with selection bias. Do men who sauna bathe take a
more general interest in their health? Do they also eat better, exercise more,
have a lower blood pressure etc?

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hammerandtongs
"""After adjustment for CVD risk factors"""

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gwern
It's a good thing all possible CVD risk factors were measured without
measurement error, included in the analysis, and had exactly correct
coefficients despite sampling error.

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hammerandtongs
It's a good thing we never make any decisions without perfect information.

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gwern
It's a good thing observational studies like these are not notorious for never
replicating and for motivating enormously costly (financially, medically, and
personally) fiascos such as the wars on salt and cholesterol.

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cowpig
Is there a way to read the paper without signing up or paying money?

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xaa
Go nuts.

[https://www.dropbox.com/s/2zdys9hzpr6a7ln/ioi140152.pdf?dl=0](https://www.dropbox.com/s/2zdys9hzpr6a7ln/ioi140152.pdf?dl=0)

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cgh
I wonder if there are similar cardiovascular benefits for hot tubs. Could it
be that it's breathing the hot air in the sauna that's beneficial rather than
a general increase in body temperature?

I'm asking because we are thinking about installing a hot tub at some point.

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blennon
Martin Pall hypothesizes that sauna therapy increases the availability of
tetrahydrobiopterin (BH4) through multiple mechanisms [1]. A small study with
people with chronic fatigue syndrome provides evidence to confirm this [2] (I
don't think this publication is peer reviewed). I believe there is an
association between BH4 and cardiovascular health, but this is not my field.

[1]
[http://www.ncbi.nlm.nih.gov/pubmed/19581054](http://www.ncbi.nlm.nih.gov/pubmed/19581054)
[2]
[http://www.townsendletter.com/Nov2013/sauna1113.html](http://www.townsendletter.com/Nov2013/sauna1113.html)

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cpncrunch
Martin Pall has a history of dubious hypotheses. It seems more likely that it
is simply the increase in heart rate that improves cardiovascular health.

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fsiefken
Alternating hot and cold showering or even only a cold shower each day, or a
few days a week has als been shown to be healthy.

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mkempe
source?

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stretchwithme
Not sure this proves anything.

People in pain are more likely to seek such relief. People in pain tend to be
less healthy and more likely to die soon.

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xaa
Sauna bathing is associated with _reduced_ risk ;)

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stretchwithme
yeah, I misread that completely.

