#037 Dr. Jari Laukkanen on Sauna Use for the Prevention of Cardiovascular & Alzheimer's Disease

Sauna frequency and cardiovascular mortality reduction

Dr. Laukkanen presents the core findings from the 20-year Kuopio study showing that men using the sauna 4-7 times per week had 50% lower cardiovascular mortality compared to once-a-week users, even after adjusting for confounders like exercise, BMI, smoking, and socioeconomic status.

"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 adjustment for other risk factors which have been also measured in this big population-based study there was still significant association between the use of sauna and these outcomes. Yeah, so if I 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 percent 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? That's correct. 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. 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. Yeah. If I remember correctly. You also looked at socioeconomic status and physical activity, which is important. Yeah. So these were all, the data is reflective really of sauna use. not you know because people that use the sauna tend to also exercise more so you know it's the you have to correct for all those other possible confounding factors which you did yeah um so the the the cardiovascular rate of mortality were there certain like were you measuring all sorts of different ways people can die from heart failure like like coronary artery disease, heart attack? Were there certain atherosclerosis? Was that looked at? Was it multiple different types of outcomes? Yeah, there were different kind of outcomes. There were heart-related, like coronary heart disease, mortality, and also sudden cardiac death was one of the outcomes. Then we have overall cardiovascular disease death as an outcome, and then also all-cause mortality. And there was a significant association with all these outcomes. Right. We'll get to all-cause mortality in just a minute, but I kind of want to talk about the cardiovascular-related mortality. It's so important because I know in the United States, heart attacks or 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? Yeah it is still number one. 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 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? 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 sauna use can decrease blood pressure level."

Optimal sauna duration and temperature for health benefits

Laukkanen discusses the dose-response relationship for sauna duration, noting that sessions under 10-15 minutes may not be enough. The optimal protocol from the study was at least 20 minutes at 79 degrees Celsius (174F), with heart rate reaching levels similar to moderate-intensity exercise.

"And so blood pressure is one of the most important factors which can explain the findings. And do you know why sauna lowers blood pressure? Do you? There may be many reasons. We know that it can balance autonomic nervous system as well, and also it can improve the vessel function. Endothelial cells? 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. Wow. So a lot of these parameters that you just described are also known to be affected by cardiovascular exercise. Yeah. Right? Yeah. Aerobic exercise. So I have to mention that as someone that uses the sauna, when you sit in the sauna for 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... 20 or 150. 150 beats per minute. Yeah. It is quite high, actually. It is something like the moderate level of physical activity. 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. Yeah, yeah. The risk reduction can be seen among those who were more than 20 minutes per session in sauna. There was a risk reduction among those men. 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. Yeah. But you also don't want to not stay long enough to get these important benefits, you know, these cardiovascular benefits. Yeah. 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 this sort of benefit, how long they should stay in? Probably depends on temperature as well. Yeah. Yeah. On the basis of this study, we defined that 20 minutes could be enough, but at the moment, actually, we are exploring more carefully what could be the time that's needed to stay at the sauna, in the sauna. And it can 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. Great. So you're working on those parameters right now. What was the average temperature that these men were using? How hot was it? It was 79 Celsius. 79 Celsius."

Sauna use linked to 65-66% lower Alzheimer's and dementia risk

Rhonda Patrick explains the connection between heat shock proteins and neurodegenerative disease prevention. Laukkanen's lab found that frequent sauna use was associated with a 66% reduction in dementia and 65% reduction in Alzheimer's disease at 20-year follow-up, following the same dose-response pattern as the cardiovascular findings.

"But heat shock, so when those proteins become damaged, they misfold, and they don't get degraded properly. So when this happens in the brain, 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, associative studies looking at heat shock proteins and neurodegenerative diseases. So there's 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. They're activated under conditions of stress, particularly heat stress. So I think that would be a very interesting thing to look at. I think there are some interesting findings, some acute changes after sauna is... After the single session. Yeah, a single session in vessel and vessel function. Oh, wow. And also heart rate. And there is actually quite, there is gradual increase in heart rate during the single sauna session. Yeah, I've noticed that myself. Yeah, yeah, yeah. It is, 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 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."

Growth hormone boost and optimal timing with exercise

Discussion of sauna's effect on growth hormone (200-300% increase after a single session) and why post-workout sauna timing may be optimal. Exercise primes muscles to take in growth hormone and IGF-1, which also crosses into the brain to support BDNF and neurogenesis.

"Growth hormone goes up like 200% to 300%, like even after a single sauna session."