Laukkanen. I'm a little excited to be sitting here with
Jari because I've talked quite a bit about his research involving using saunas and how
that has been shown to improve cardiovascular health and also improve overall longevity.
And, to my knowledge, this is actually...Your
work is the first research that I've actually seen in humans to show that using the sauna,
you know, can improve longevity. Maybe we can start off by talking about this
study that you did and published about a year ago, I believe, in "The Journal of American
Medical Association," "JAMA," looking at the use of the saunas and sauna frequency and
cardiovascular-related mortality and overall mortality rate. So can you tell us a little bit about the
study itself? [Jari]: Yeah, yeah, yeah. Yeah.
Thank you. Our study is based on middle-aged population
from Eastern Finland. And at baseline, we measured the use of sauna,
how many times per week and how long time per one session and what was the temperature,
and on the basis of this information, we have studied the association between the use of
sauna and fatal cardiovascular outcomes and mortality. And in this study, we found, really, that
sauna use was inversely associated with the risk of fatal coronary heart disease events
and all-cause mortality.
And, after assessment for other risk factors
which have been also measured in this big population-based study, there were still significant
association between the use of sauna and these outcomes. [Rhonda]: Yeah. So if remember correctly, your study showed
that men that used the sauna two to three times a week had a 27% lower cardiovascular-related
mortality compared to men that used it one time a week. And men that used the sauna four to seven
times a week actually had a 50% lower cardiovascular-related mortality than men that used the sauna one
time a week, and that is very robust.
So you followed these men for 20 years? [Jari]: Yeah, yeah. The total follow-up time was 20 years, and
we have annually measured new outcomes, and we have followed carefully from baseline until
the end of the follow-up. And, yes, the risk reduction was really, really
obvious and clear, yeah. [Rhonda]: And you said you adjusted for other
risk factors meaning, like, obesity, you looked for people...Like obesity, smoking, alcohol,
cholesterol, type 2 diabetes, these sort of factors? [Jari]: Yeah.
[Rhonda]: If I remember correctly, you also
looked at socioeconomic status and physical activity, which is important. So these were all...The data's reflective
really of sauna use not, you know, because people that use the sauna tend to also exercise
more so, you know, you have to correct for all those other possible confounding factors,
which you did. So the cardiovascular rate of mortality, were
there certain...Like, were you measuring all sorts of different ways people can die from
heart failure? Like coronary artery disease? Heart attack? Are there certain, like atherosclerosis? Was that looked out? Was it multiple, different types of... [Jari]: Outcomes? [Rhonda]: Outcomes.
[Jari]: Yeah, yeah. There were different kinds of outcomes. There were heart-related like coronary heart
disease mortality and, also, sudden cardiac death also one of the outcomes. Then we have overall cardiovascular disease
death as an outcome and then, also, all-cause mortality.
And there was significant association with
all these outcomes. [Rhonda]: Right. We'll get to all-cause mortality in just a
minute, but I kinda want to talk about the cardiovascular-related mortality. It's so important because I know in the United
States, heart attacks are, you know, cardiovascular disease is the number one killer followed
up by cancer and then respiratory diseases, but Alzheimer's disease is actually climbing
up.
In Finland, I believe, cardiovascular disease
is also the number one killer, correct? [Jari]: Yeah. It is still the one. Yeah. [Rhonda]: Yeah, so, you know, if you can do
something that lowers your risk by, you know, 50%, I mean, that's very significant.
What do you think? I have my own sort of, you know, I've done
some reading on how the sauna affects in different vascular functions, but you're a cardiologist,
so do you have some sort of...Do you speculate on some of the mechanisms by which using the
sauna can improve cardiovascular health? [Jari]: Yeah. Yeah, we have been studying also these mechanisms,
which can be explained to our findings. And one of the most important is the blood
pressure because sauna use, long-term sauna use, can decrease blood pressure level. Actually, we have studied in the same population
and found that there is a reduction of incident hypertension among those who are using more
sauna compared to those who have only, let's say, one session per week.
And so blood pressure is really one of the
most important factors which can explain the findings. [Rhonda]: And do you know why sauna lowers
blood pressure? Do you? [Jari]: There may be many reasons. We know that it can balance the autonomic
nervous system as well and, also, it can improve the vessel function. [Rhonda]: Endothelial cells? [Jari]: Yeah, endothelial cells.
And another thing is that sauna may have some
effect on arterial stiffness, and compliance of arteries can improve after long-term sauna
use. [Rhonda]: Wow. So a lot of these parameters that you just
described all also known to be affected by cardiovascular exercise, right? [Jari]: Yeah, yeah. [Rhonda]: Aerobic exercise.
So I have to mention that, like, you know,
as someone that uses the sauna, when you sit in the sauna for, you know, a long-enough
period of time, your heart rate starts to elevate, as if you were doing cardiovascular
work. In fact, I think it's something like 100... [Jari]: Twenty or 150. [Rhonda]: 150 beats per minute.
[Jari]: Yeah. It is quite high actually. It's something like a moderate level of physical
activity. [Rhonda]: So you mentioned the duration, the
time people spent in the sauna also was an important factor on the robustness of lowering
cardiovascular-related mortality.
So people that stayed in the sauna, I believe
it was longer than 19 minutes had the most robust effect compared to men that stayed
in less than 11 minutes, something? [Jari]: Yeah, yeah, yeah. Yeah, the risk reduction can be seen among
those who more than 20 minutes per session in sauna. They was a risk reduction among those men. [Rhonda]: Yeah.
I'm always sort of hesitant to tell people,
like, they ask, you know, "Well, how long should I stay in the sauna?" Because on the one hand, you don't want to
stay in too long, but you also don't want to not stay long enough to get these important
benefits, these cardiovascular benefits. So do you have any, sort of, parameters or
guide that, you know, someone that's trying to figure out how long to stay in the sauna
in order to get these sort of benefit, how long they should stay in? Probably depends on temperature as well. [Jari]: Yeah, yeah. On the basis of this study, we found that
20 minutes could be enough, but at the moment, actually, we're exploring more carefully what
could be the time that's needed to stay in the sauna, and it can't be that very short
time, let's say 10 minutes or 15 minutes.
It's not enough to get all these health benefits,
maybe. So we try to clarify what is the optimal time
to stay in sauna. [Rhonda]: Great. So you're working on those parameters right
now.
What was the average temperature that the
sauna that these men were using? How hot was it? [Jari]: It was 79 celsius. [Rhonda]: Seventy-nine degrees Celsius? So about 20 minutes in a 79-degrees Celsius
sauna was what was important for, at least in the context of the lower cardiovascular-related
mortality and also all-cause mortality as well? [Jari]: Yeah, yeah. That was our primary finding. [Rhonda]: And what was the type of sauna that
these men are using? Because this is Finland, right? [Jari]: Yeah, yeah.
It's Finland, yeah. For us it is clear that it is Finnish dry
sauna. Yeah, it's relatively dry. [Rhonda]: Relatively dry? So they weren't doing that...
What's it called when you dump that water
on? [Jari]: Lyly? [Rhonda]: Lyly. So that when you make the humidity you do
the lyly? [Jari]: Yeah. Yeah. [Rhonda]: Was that also...
[Jari]: It was also allowed in the use, yeah. [Rhonda]: So the all-cause mortality is also
interesting because your study showed that, again, there was a dose-dependent effect where
men that used the sauna two to three times a week had a 24% lower all-cause mortality
than men using it one time a week. And I believe it was men using it four to
seven times a week was a 40% lower all-cause mortality? [Jari]: Yeah, it was...Yeah, yeah. We're calling those dose-response relation.
[Rhonda]: Right, yeah. So you're getting ready to publish...A paper
was accepted that you're going to publish, which will probably be published by the time
this video is published, so that's really exciting. So you found that sauna use is associated
with lower Alzheimer's disease and dementia. That is extremely interesting to me because,
you know, of my interest in heat shock proteins.
So the sauna, one of the most robust molecular
mechanisms, you know, that happens upon heat stress. So when you heat-stress the body, what happens
is that you activate a signaling pathway called heat shock proteins. They play a very important role in maintaining
the three-dimensional structure of a protein, which is important, obviously, for protein's
function, but it's also very important for the half-life of the protein. And when the three-dimensional structure of
a protein becomes misfolded because of damage that's occurring, you know, damage that, damage
their DNA, the same damage that does that damages these proteins, you know, by-products
of normal metabolism.
Reactive oxygen species, by-products of, you
know, immune activation, these things are damaging our proteins, our DNA, our cells. But heat shock...So when those proteins become
damaged, they misfold, and they don't get degraded properly. So when this happens in brain, you know, proteins
can start to then aggregate and form these plaques, protein aggregates and plaques. So probably the most well-known one is amyloid-beta
42, which is associated with Alzheimer's disease.
But interestingly, heat shock proteins, what
their function is inside of the cell is to actually repair a misfolded protein so that
it maintains its proper three-dimensional structure again. So they're basically preventing the protein
aggregation, and this has been shown in multiple studies in rodents, in lower organisms. There's been many, many studies, associated
studies looking at heat shock proteins and neurodegenerative diseases. So there is a lot of interest in how heat
shock proteins may be a therapeutic target for preventing neurodegenerative diseases
like Alzheimer's and also Parkinson's disease.
And I've always thought, you know, the connection
between knowing the sauna activates heat shock proteins, I mean, that's their name, you know? They're activated under conditions of stress,
particularly heat stress. So I think that would be a very interesting
thing to look at. [Jari]: I think there some interesting findings,
some acute changes after sauna use. [Rhonda]: After just a single session? [Jari]: Yeah, single session, in vessel and
vessel function.
[Rhonda]: Oh, wow. [Jari]: And also heart rate. There is a gradual increase in heart rate
during the sauna, single sauna session. [Rhonda]: Yeah, I've noticed that myself.
[Jari]: Yeah, yeah, yeah. When you stay, let's say, 15 minutes in sauna,
it's quite easy. It's not demanding. But after that, it becomes more and more demanding
to stay in sauna, and your heart rate will increase.
[Rhonda]: I know there is a bunch of endocrine
factors that increase quite dramatically upon just even a single sauna session, like, for
one, growth hormone. [Jari]: Growth hormone, yeah, it is, yeah. [Rhonda]: Growth hormone goes up, like, 200%
or 300%, like, even after a single sauna session. [Jari]: Yeah, it's quite much, yeah, yeah.
[Rhonda]: And growth hormone, you know, it
plays an important role in preventing muscle atrophy, which is also linked to longevity,
right? The more muscle mass you have and more muscle
strength is associated with lower all-cause mortality, so that would be interesting to
see if that's also related. Do you have any thoughts on whether or not,
like, someone who is doing physical activity like doing some kind of a workout exercise,
whether they should use the sauna before or after their workout? [Jari]: This is very interesting question
to see if there's even more clear effects on vessel function and so on if you have an
exercise before and then you go to sauna. Actually, we're normally doing that quite
often in Finland. [Rhonda]: So you normally do the sauna after
exercise, after a workout? [Jari]: Yeah.
[Rhonda]: Yeah, that's what I do as well,
you know? And if you think about it too, it's also the
perfect time to get that growth hormone boost, you know, because you've just worked your
muscles, so you need that repair, and also the exercise primes your muscles to take in
the growth hormone, take in actually IGF-1, which is downstream of growth hormone. So your IGF-1 goes in muscle tissue and also
into the brain. So the exercise sort of primes that IGF-1
that's released downstream of growth hormone from the sauna to go into the brain, where
it plays a role in actually helping BDNF, brain-derived neurotrophic factor, in growing
your neurons. So it's always sort of a question, like, do
you do it before a workout or after? And I've always been inclined to do it after
a workout, but it would be interesting to know if there's, you know, specifically, if
it's affecting, you know, vessel function or things like that.
[Jari]: Yeah, yeah. We're very interested to see the effects on
vessel function after exercise which is combined with sauna and what are the parameters, what
are the values after that? And because there are also some evidence that
maybe after a strength training, you know, it can be even that the arterial stiffness
may increase a bit maybe in some cases. [Rhonda]: Oh, really, after strength training? [Jari]: So if you go to sauna, you can relax
and improve your vessel function also. [Rhonda]: Wow, that's interesting.
So maybe better to do the sauna after strength
training also because... [Jari]: Yeah, yeah, yeah. But, yeah, this is, we have no... [Rhonda]: You're speculating.
[Jari]: Speculating, yeah, yeah. [Rhonda]: You're speculating, of course. Yeah, yeah, I mean, but it's okay to speculate. Speaking of speculating, so something else
that I find very interesting is the effect on mood.
Actually, it's what got me interested in the
sauna in the first place. So when I was in graduate school, I was very
stressed out, you know, exams and failed experiments and lots of pressure, so I was using the sauna
and it noticeably improved my mood and helped me deal with stress. It helped me deal with the anxiety I was experiencing. And there is a lot of, sort of, speculative
reasons, I think, that's possible, but one is related to cardiorespiratory fitness.
So there's actually been studies, one very
recently done, published, in a very large sample of people, I believe it was like a
million people, looking at cardiorespiratory fitness and depression. And the study found that people with poor
cardiorespiratory fitness had a 75% increased chance of being...Have been, you know, diagnosed
with depression. So I'm sort of interested in...Clearly the
sauna is affecting, you know, cardiovascular health. And do you know, like, cardiovascular fitness
would be, you know, one way to...A measurement of cardiovascular health.
Have you ever looked at cardiorespiratory
fitness? [Jari]: Yeah, we have been measuring, also,
cardiorespiratory fitness in our study also in this new study path we have measured, and
we can see if there's association between the fitness, and sauna use, and these different
parameters. Yeah, yeah. [Rhonda]: So that's ongoing right now? [Jari]: Yeah, ongoing in our population-based
study, although we have adjusted for the level of fitness, yeah, there are also independent
associates between the use of sauna and outcomes. [Rhonda]: Oh, cool.
So but you're saying, you know, in addition
to people, obviously, that are physically active, you're adjusting for that, and they're
trying to look just specifically at how the sauna may, in and of itself, affect cardiovascular
fitness. [Jari]: Yeah, itself. [Rhonda]: That will be really great. I look forward to that.
The other one which I won't get into too much
detail because I don't want to talk so much, but it affects endorphins. So sauna releases endorphins. Endorphins make you feel better. [Jari]: Feel better, yeah, yeah.
It's relaxation, yeah, yeah. Also, in Finland, I think quite many use it
for that purpose. They want some relaxation, you know, after
working day and so on. It's like a happy to end your day and go to
sauna and after that you feel more relaxed.
[Rhonda]: Do you think that may also have
to do with the improved longevity? Because stress is also linked to longevity,
and so if it's something that's lowering stress and making you more relaxed, that seems like
it goes hand-in-hand with longevity as well. [Jari]: Yeah, it can be. There are studies showing the role of autonomic
nervous system and cardiovascular diseases, how they are related together. And also in our study we want to explore how
the sauna may have effect on heart rate and heart rate variability, which is one of the
measures that can be used to assess the autonomic nervous system and its function.
[Rhonda]: Oh, great. Having been in Finland now for a few days
and having the privilege of going to The Finish Sauna Society and also hanging out with some
other friends here in Finland, I've had a chance to experience the sauna culture, the
traditional smoke saunas, and also the other, you know, dry saunas and the Lyly. [Jari]: Lyly, yeah. [Rhonda]: But what I also noticed is that
almost a 100% of the Finnish people that use the sauna, after the sauna, like to go run
into a jump into a cold lake or the Baltic or something cold, very, very cold.
And they do this, you know, several times. I mean, it seems to be a very normal part
of Finnish sauna culture. Is that accurate, you would say? [Jari]: Yeah, yeah. Many people are using.
I know it, yeah, yeah. [Rhonda]: So I have a question on whether,
you know, what is the safety? Is there any safety issues? Because I've read a couple of case reports
where because you're going from hot sauna where vasodilation is occurring and then you're
going into cold where vasoconstriction is occurring, norepinephrine is being released
and vasoconstriction is occurring. There have been a couple of documented cases
of, like, coronary artery spasm, I think it's called. Maybe do you think there is a potential risk
of going from hot to cold in terms of people with maybe a pre-existing heart disease or
something? [Jari]: Yeah, among those patients who have
coronary heart disease and, especially if it's not stable condition then you have to
be very careful.
You cannot do that because there can be a
spasm in the coronary artery, so it can be harmful, yeah. [Rhonda]: But for the most part of the population,
it seems to be pretty safe. I mean, I've done it before, and it feels
really good. I mean, you feel amazing after doing the hot
and cold.
Also interested in if it blunts any of the
positive effects, but what's interesting is I've seen that cold also activate heat shock
proteins because heat shock proteins are part of the stress response, you know? It's called hormetic stress. Are you familiar with hormesis? It's like a little bit of good stress where
it's not too much stress, but it's enough stress to activate all of these genetic pathways
that help you deal with stress. Well, heat shock proteins are one of those
genetic pathways. And so cold is also a little bit of a hormetic
stress, and exercise activates heat shock proteins as well.
But heat robustly activates them, very robustly. It's good to know that both the hot and the
cold are activating some of the same good genetic pathways. So maybe you're not negating all the good
stuff you just did with the sauna, right? Maybe there's synergy. [Jari]: We would be really happy to investigate
those possible mechanisms between sauna and memory disease, because we have been thinking
through, you know, more like improve cardiovascular system, and circulation, and these, if they
have a effect on the memory diseases because some cardiovascular diseases and memory diseases
are sharing the bit similar risk factors.
[Rhonda]: Yeah, like vascular dementia. Of course, yeah, blood flow is absolutely
linked to dementia. So there's probably multiple mechanisms by
which the sauna... [Jari]: Multiple mechanisms, yeah.
[Rhonda]: Man, it's great. We gotta get the word out there, you know,
more research, more people using the sauna. I think that's... [Jari]: Because I think nowadays there are
so many studies showing the positive effects of physical exercise on these outcomes and
vessel function and so on, but there are quite limited data on sauna use, and warm exposure,
and these similar outcomes, so there are space to do this kind of research.
[Rhonda]: Yeah. You're like, you know, an explorer in new
territory, and no one is really doing this, you know, and it's really great. I'm very glad that someone is, you know, so
please keep up the good work. [Jari]: And in the best case, of course, we
can combine these positive effects in, like, exercise and sauna.
[Rhonda]: Exactly. Are you going to look at that as well? Are you going to see if there is a synergy? [Jari]: Yeah, yeah, we try to do something,
yeah. What is also important for public health level
that also we have to emphasize that there many other factors in addition to exercise
and sauna, there are other also. Of course, we have to take care of other risk
factors like blood pressure, lipids, smoking, obesity in addition to that.
[Rhonda]: Yeah. Cool. Well, Jari, thank you so much for taking time
to speak with me and I know you're on Twitter. I follow you on Twitter.
Do you want to say your Twitter handle name
because it's your name backwards, I think? [Jari]: Yeah. You're welcome to follow, yeah. [Rhonda]: Can you spell it out for people? [Jari]: Jari Laukkanen. [Rhonda]: Right, but your Twitter handle is
LaukkanenJari, I think.
So, yeah, L-A-U-K-K-A-N-E-N-J-A-R-I. That's your Twitter handle, yeah. Okay, excellent. Well, thank you again, Jari.
[Jari]: Thank you. Thank you so much. [Rhonda]: Special thanks to Dr. Laukkanen
for meeting with me, and for even making special allowances for my unpredictable schedule while
I visited Finland, allowing me to drop in his home late in the evening for a quick conversation.
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