Getting serious about saunas

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In 2017, researchers reported that regular episodes in a sauna can dramatically reduce one’s risk of developing neurodegenerative conditions, like Alzheimer’s and Parkinson’s.

Recently, a member of the Parkinson’s community shared another feature of “sauna life” that helps them: they sleep better after a short sauna session right before bed.

In today’s post, we will discuss some of the research associated with the use of saunas.

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Source: Twitter

Fun fact: Finland has over 3 million saunas.

It is a rather impressive number considering that there is only 5.5 million people in the country. So important to the Finnish culture is the humble sauna that Unesco recently registered the sauna on its list of Intangible Cultural Heritage.

You will find a sauna at every public swimming pool, most hotels, private residence, and summer homes by the lake or the sea in Finland.

They are everywhere.


Just as the sport of rugby is central to everything in New Zealand (seriously, it’s like a religion), sauna life is an important corner stone of Finnish society. They love it.

Does this actually have anything to do with Parkinson’s?

Yes, it does. For two reasons.

First, several years ago, Finnish researchers published this study:

Title: Sauna bathing is inversely associated with dementia and Alzheimer’s disease in middle-aged Finnish men
Authors: Laukkanen T, Kunutsor S, Kauhanen J, Laukkanen JA.
Journal: Age Ageing. 2017 Mar 1;46(2):245-249.
PMID: 27932366                 (This report is OPEN ACCESS if you would like to read it)

In this study, the investigators conducted a population-based prospective cohort study. This means that they tracked a group of research participants over time to see if they can find associations between their life styles and subsequent medical conditions.

The cohort that was followed in this study were part of a larger project called the Kuopio Ischemic Heart Disease risk factor study, which involved annual monitoring for dementia and cardio-metabolic outcomes. This population is assessed annually, and as a result the researchers have very large datasets to analyse.

Their cohort involved 2,315 apparently healthy men (aged 42–60 years) at the start of the study (which was between 1984 and 1989 for the baseline assessments).

During the follow up period – which was on average 20.7 years (interquartile range 18.1–22.6) – the investigators asked the participants lots of questions during their assessments, including their frequency of sauna bathing. Over the follow up period, the researchers recorded a total of 204 and 123 diagnosed cases of dementia and Alzheimer’s disease within the cohort.

Sauna at ice hockey stadium in Finland. Source: Pinterest

But here’s the interesting part: When they analysed their data, the researchers found that the men participating in sauna bathing 2–3 and 4–7 times per week had a 0.80 and 0.35 hazard ratio for developing Alzheimer’s disease (compared to men who sauna once per week or less).

Interesting. What does that mean: hazard ratio?

A hazard ratio is a measure of how often a particular event happens in one group compared to how often it happens in another group, over time. A hazard ratio of 1 indicates a lack of association, while a hazard ratio of greater than 1 (say, 1.50) suggests an increased risk of the event, and a hazard ratio below 1 (such as 0.75) suggests a smaller risk.

So 0.35 hazard ratio means that sauna bathing 4–7 times per week was associated with a very reduced likelihood of developing Alzheimer’s?

In a nut shell, yes.

And the researchers concluded that “moderate to high frequency of sauna bathing was associated with lowered risks of dementia and Alzheimer’s disease“.

Does this also apply to Parkinson’s?

There is currently no data to suggest any association between habitual sauna bathing and Parkinson’s (and I’m happy to be corrected on this).

But they have observed a similar reduced risk of stroke in individuals who sauna bath regularly (Click here to read more about this).

Did they speculate as to how sauna bathing could result in reduced risk of dementia?

Yes. The current thinking is that regular sauna bathing activates heat shock proteins.

What are heat shock proteins?

Heat shock proteins are a large family of proteins that act as molecular chaperones, and they are induced in cells during periods of stress conditions produced by cellular insult, environmental changes (such as a change in temperature), infections, etc.

Molecular chaperones are proteins that assist in the correct folding or unfolding of large proteins to ensure appropriate cell function.

Source: Sciencedirect

So the researchers were speculating that by regularly sauna bathing, individuals are causing the activation of these heat shock proteins which improve the folding and unfolding of proteins, and thus reducing the likelihood of misfolding proteins building up in cells.

I see. Interesting. So is that it? The end of the post? Summing up time?

No, not just yet.

There is a Parkinson’s-related reason for sharing this Alzheimer’s-sauna research.

What is it?

I was recently speaking with a Parkinson’s advocate who has a habit of self-experimentation, and he told me about his sauna bathing activities.

Specifically, he told me about how short sessions in the sauna, just before bed, had considerably improved his sleep patterns.

Interesting. What exactly is he doing?

For the last nine months, he has been using a conventional sauna (at 180 degrees F/80 degrees C for 20 mins per session) 6-7 days/week just before going to bed. He adds that keeping properly hydrated is a very important part of the regimen.

He felt that it had improved sleep quality and levels of fatigue, as well as improving overall sense of well-being. I am mentioning this here, because disrupted sleep patterns is a common problem for many people with Parkinson’s.

That seems very hot. Is it safe?

First thing to state here is that this is anecdotal information. And it has not be confirmed by proper scientific investigations. Normal conventional sauna temperatures range between 150°F and 195°F (65°C to 90°C), so it would not be considered extreme. But people with Parkinson’s can have issues with their autonomic nervous system (part of the peripheral nervous system that controls involuntary or unconscious actions within the body like temperature regulation), so caution is advised. And sauna bathing should not be conducted by oneself.

The second thing to state here is that sauna bathing may not be the only way to achieve these results.

What do you mean?

Researchers have shown that simply taking a warm/hot shower before bed can significantly improve the quality of sleep as well as reducing the period of time before one actually achieves sleep.

Source: Dherbs

A meta-analysis of 13 human clinical studies concluded that water-based passive warming of skin – for as little as ten minutes, between one and two hours before sleep – improved self-rated sleep quality and shortened sleep latency by approximately 36% (Click here to read more about this).

Sleep behaviour and body temperature in people with Parkinson’s has been studied and it was found that lower night time core body temperatures correlated with the severity of rapid eye movement (REM) sleep behaviour disorder symptoms (this is where individuals physically act out their dreams in bed). This was also associated with a reduction in the percentage of REM sleep and prolonged sleep latency (click here to read more about this research). So there might be something to this idea of warm shower bathing before bed to help with sleep.

In fact, one does not even need to warm the whole body to shorten the period of time before one falls to sleep.

You only really need to warm the hands and feet.


There are numerous studies, from independent labs, demonstrating that just warming of the hands and feet promotes the rapid onset of sleep (Click here, here and here to read more about this).

This study showed how lower-limb warming improved sleep quality in elderly people living in a nursing home:

Title: Lower-limb warming improves sleep quality in elderly people living in nursing homes.
Authors: Oshima-Saeki C, Taniho Y, Arita H, Fujimoto E.
Journal: Sleep Sci. 2017 Apr-Jun;10(2):87-91.
PMID: 28966746          (This report is OPEN ACCESS if you would like to read it)

In this study, the researchers recruited seven elderly women (aged 74-93 years) in a care home and treated them every night with warming of the their legs with heat packs (heated to 42ºC) for 40 minutes every night over 8 weeks:

Wrapping heat packs around the legs. Source: PMC

The results showed that lower-limb warming with heat packs sped up the onset of sleep and reduced the number of wake episodes after sleep onset, thus improving the overall quality of sleep.

For anyone seeking more information about “heat therapy” for Alzheimer’s and Parkinson’s (Click here to read more on this topic), and for those who prefer cold temperatures to hot, have a read of a previous SoPD post on the Wim Hof method (Click here to read that post).

So what does it all mean?

This winter my wife discovered the pleasure of an electric blanket. With the cost of heating sky rocketing in the UK, we have limited our heating of the house and sought alternative solutions. One such hack has been the purchase of an electric blank for our beds. We turn it on 20-30 minutes before bed, and turn it off as we get in.

My wife has noticed that she falls asleep a lot quicker when the electric blanket has been on (and she sleeps better) than when it hasn’t. I’m not overly impressed by the rapidity at which she reaches unconsciousness you understand, but I have to admit that it is agreeable to climb into a nice warm bed and drift off to sleep.

Sleep is a necessary component of human existence – and it is one that is disrupted for many people with Parkinson’s, so any remedies that could have added benefits (like activation of heat shock proteins) is deserving of further research. We have explored sleep and Parkinson’s in previous SoPD posts (Click here to read an example), and are always on the look out for new ideas on improving sleep patterns. So when a Parkinson’s advocate shared his life hack with me, I asked if he would mind if I wrote a SoPD post on the topic.

He kindly agreed, and I hope you have found the resulting post interesting.


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EDITOR’S NOTE: The information provided by the SoPD website is for information and educational purposes only. Under no circumstances should it ever be considered medical or actionable advice. It is provided by research scientists, not medical practitioners. Any actions taken – based on what has been read on the website – are the sole responsibility of the reader. Any actions being contemplated by readers should firstly be discussed with a qualified healthcare professional who is aware of your medical history. While some of the information discussed in this post may cause concern, please speak with your medical physician before attempting any change in an existing treatment regime.

The banner for today’s post was sourced from twitter

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