7 ms·

Association Between Sauna Bathing and All-Cause Mortality Events

34 points by mkempe 12y ago

JoeAltmaier 12y ago
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?
- hammerandtongs 12y ago
  """After adjustment for CVD risk factors"""
  - kgwgk 12y ago
    Eating well and exercising are hard to quantify and control for.
  - gwern 12y ago
    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.
    - hammerandtongs 12y ago
      It's a good thing we never make any decisions without perfect information.
      - gwern 12y ago
        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.
cowpig 12y ago
Is there a way to read the paper without signing up or paying money?
- xaa 12y ago
  Go nuts. https://www.dropbox.com/s/2zdys9hzpr6a7ln/ioi140152.pdf?dl=0 https://www.dropbox.com/s/2zdys9hzpr6a7ln/ioi140152.pdf?dl=0
cgh 12y ago
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.
- blennon 12y ago
  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
  - cpncrunch 12y ago
    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.
fsiefken 12y ago
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.
- mkempe 12y ago
  source?
maj0rhn 12y ago
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.
- woah 12y ago
  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.
  - maj0rhn 12y ago
    $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.
    - hammerandtongs 12y ago
      """saunas are even more prevalent in Scandinavia. You should rethink your reasoning."""
eloff 12y ago
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?)
- pacaro 12y ago
  Given that the study was conducted in Finland, it's unlikely that wealth is a confounding factor in sauna usage.
  - eloff 12y ago
    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.
stretchwithme 12y ago
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.
- xaa 12y ago
  Sauna bathing is associated with reduced risk ;)
  - stretchwithme 12y ago
    yeah, I misread that completely.
- rlpb 12y ago
  Right - that's why the abstract talks of of an "association". Correlation, not causation.
maj0rhn 12y ago
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.
- mkempe 12y ago
  It's based on a 30-year long longitudinal study of Finnish men, not a miniature people-in-the-sauna "study".
- mkempe 12y ago
  What is the evidence that multiple sclerosis is "big in Finland"?
bemmu 12y ago
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
jhou2 12y ago
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.

34 points by mkempe 12y ago

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?

hammerandtongs 12y ago
"""After adjustment for CVD risk factors"""
- kgwgk 12y ago
  Eating well and exercising are hard to quantify and control for.
- gwern 12y ago
  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.
  - hammerandtongs 12y ago
    It's a good thing we never make any decisions without perfect information.
    - gwern 12y ago
      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.

cowpig 12y ago

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

xaa 12y ago
Go nuts. https://www.dropbox.com/s/2zdys9hzpr6a7ln/ioi140152.pdf?dl=0 https://www.dropbox.com/s/2zdys9hzpr6a7ln/ioi140152.pdf?dl=0

cgh 12y ago

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.

blennon 12y ago
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
- cpncrunch 12y ago
  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.

fsiefken 12y ago

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.

mkempe 12y ago
source?

maj0rhn 12y ago

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.

woah 12y ago
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.
- maj0rhn 12y ago
  $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.
  - hammerandtongs 12y ago
    """saunas are even more prevalent in Scandinavia. You should rethink your reasoning."""

eloff 12y ago

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?)

pacaro 12y ago
Given that the study was conducted in Finland, it's unlikely that wealth is a confounding factor in sauna usage.
- eloff 12y ago
  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.

stretchwithme 12y ago

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.

xaa 12y ago
Sauna bathing is associated with reduced risk ;)
- stretchwithme 12y ago
  yeah, I misread that completely.
rlpb 12y ago
Right - that's why the abstract talks of of an "association". Correlation, not causation.

maj0rhn 12y ago

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.

mkempe 12y ago
It's based on a 30-year long longitudinal study of Finnish men, not a miniature people-in-the-sauna "study".
mkempe 12y ago
What is the evidence that multiple sclerosis is "big in Finland"?

bemmu 12y ago

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

jhou2 12y ago

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.