sauna has earned its place in recovery culture. Heat feels restorative, the ritual is simple, and the research around cardiovascular health is genuinely interesting. But a strong ritual does not need exaggerated certainty to be valuable.
This transcript has been lightly cleaned from the source captions for readability while preserving the original sequence.
hey y'all this is uh kevin bass from the dot wars. com i'm a medical student and phd student uh finishing my phd and about to finish my medical degree as well and head out to the uh to the great world of clinical medicine soon um but in you know my spare time i like to dispel misinformation and of course learn more about science and these two activities are actually closely tied together for me because sometimes i'll hear some sort of claim i'll be like hmm is that really true because i'm gonna know like if it's true then maybe we can use that information and then i'll look deeper into it i'll find usually the more sensational claims are not true and so uh that's what i've done here i saw this clip on youtube or sorry it was instagram actually um podcast number 277 in the lex friedman podcast with andrew Huberman and um they they're here they're talking about sauna and i'm what i'm going to do now is i'm going to systematically dismantle um this misinformation about sauna use i'll explain each and every like minute detail about why it's wrong and hopefully we can get this done pretty quick but i'm going to explain every single claim let's let's hit it if you get into the sauna the way i just
described 30 minutes twice a week or three times per week you reduce the likelihood of dying of a cardiovascular event by 27 if you do it four or more times per week you reduce the probability of dying by 50 it's very clear that what you need is the release of something called dinorphin which is the terrible feeling that you get when you're in really hot temperatures it's also the terrible effect that alcoholics feel when they are in withdrawal that's what you're trying to trigger when you do that a number of things happen you set off heat shock proteins that go repair broken proteins it also makes it so that later endorphin binds its receptor more strongly all right so in this uh video i'm going to address three claims in particular first claim is his mortality benefit claims which i think are not supported by the literature and not supported by the evidence i'm going to explain exactly in precise detail how that is not the case second thing i'm going to address is this heat shock protein claim that heat shock proteins are responsible for the health effects of sauna there's no evidence that that's the case and then last we're going to talk about about dinorphin and what we know about dinorphin and in each case i'm going to show that [Music] it doesn't seem that any of his claims are supported by anything uh in the scientific literature okay so the first claim that he made was based on this
paper association between sauna bathing and fatal cardiovascular and all-cause mortality events and it showed that the more frequency you have with the sauna the uh lower your risk of cardiovascular events i'll cause mortality etc and his numbers that he used for uh the podcast with lex are exactly the same numbers that were reported by this paper so it's exactly the same thing the problem with this paper is that there was a commentary published by kivamaki and it's called the link between sonobathing mortality maybe non-causal and i want to focus on one particular criticism in particular and i'm just going to read it off simple adjustment for disease versus no disease may not entirely solve the problem of converse causation bias because it operates within disease groups the more severe disease the greater the fear of cardiac challenge consistent with this reasoning the association between saunas and cardiac death was seen in individuals with diabetes but not without uh among hypertensives but not normal intensive individuals among patients with cardiovascular disease but not their healthy counterparts a more robust finding at reduced risk of reverse causation
bias would be a graded association between number of sauna sessions and mortality in an initially healthy cardiorespiratory fit population but this was not observed we urge caution against the interpretation that saunas are a major cardiovascular prophylactic and to respond to this um well the authors responded not very compellingly and i'm going to explain why that's the case but first i want to explain like exactly what this means so this the relationship between sauna bathing and mortality and cardiovascular governance only existed in people with disease it didn't exist in healthy people it only existed in people with disease what does this mean the idea is if it also existed in healthy people that would suggest that maybe even in healthy people it's preventing it's causally preventing death or cardiovascular events but the fact that it's only happening in sick people suggests that among sick people the people who are more sick are just not able to go into the sauna whether they're you know disabled or they're too fatigued or they're afraid of the challenge of the sauna because it's a quite stressful experience to be in the sauna they're simply not going into the sauna so actually sauna bathing frequency and duration may be associated with just
reduced disease severity and if you have reduced disease severity you're less likely to die of cardiovascular events in general in the uh the near future so this relationship between sauna bathing and lower risk of disease might actually reverse causation it's actually you have lower risk of disease which causes you to be able to sauna bathe more often and this is again because this relationship between more sauna bathing and lower risk of disease was not found in healthy people it was only found in people at risk for disease or sorry with diseases with hypertension with cardiovascular disease with diabetes it was not seen in healthy people suggesting that there's a reverse causation problem going on here it's people who are really sick who are unable to do sauna bathing versus people who are less sick with those same diseases who are able to do sauna bathing who are dying more but not because they're not doing sauna bathing but because they're simply more sick this is the problem with uh with um [Music] with epidemiological research now it's not that epidemiology isn't useful it is epidemiology is useful but you have to understand what the limitations are in order to draw the right conclusions and the right conclusions are being drawn in this particular case so let's go revisit the criticism real quick and then we're going to go address a response to the criticism by rhonda patrick so here the criticism is simple adjustment for disease versus no
disease may not entirely solve this problem since reverse causation bias operates within disease groups okay so but so so ronna patrick has a response to this or at least in her review about this she has a response her view is called sauna use as a lifestyle practice to extend lifespan and she writes similarly whereas reverse causation bias figures prominently in observational studies and is a valid concern when investigating links between cardiovascular disease and lifestyle the kihd findings this is the study the original study we were talking about were adjusted for potential biases including lifestyle factors such as socioeconomic status physical activity and cardio respiratory fitness so it's just confusing because the original commentary says simple adjustment for disease versus no disease may not entirely solve this problem she's saying well they adjusted for disease versus no disease um but they didn't see a it didn't it still didn't affect the relationship but what this these guys are saying is you can't actually adjust away that problem you have to actually see the reduction in risk uh for using the sun among healthy people and you don't it doesn't matter how much adjustments you do you don't see the the reduction among healthy people okay cool
so that's like the first thing so this isn't this criticism is never really responded to it's just some summarily dismissed it's somewhere is summarily dismissed in this review so that's not good science in my opinion but we'll let's continue on to the next claim so we talk about the mortality benefit claim let's talk about the heat shock protein claim so kubernetes claims that heat shock proteins are the mediating mechanism by which sauna reduces um mortality and actually this is interesting because because ronda does the same thing she says the she says in particular the the risk of all-cause mortality was 40 lower among frequent sun users compared to infrequent users independent of conventional risk factors so it's basically going to be based on not these conventional risk factors but on stuff like as we pointed out um heat shock proteins that's that's like the mechanism that these guys are promoting but what's the problem with he shocked proteins is there's no good evidence in the heat shock protein literature that um this is the case so i'm going to read bronda's paragraph and she's got uh it says one of the protective adaptive mechanisms to heat stress is the increased expression heat shock proteins comprise a large highly conserved family of proteins that are present in all cells heat shock proteins are also present in the extracellular environment they play
a prominent role in many cellular processes including immune function cell signaling cell cycle regulation and proteome homeostasis loss of protein integrity is a hallmark of aging process and intrinsically disorder or damaged dysfunctional proteins are common features and age-related diseases such as cardiovascular disease and neurodegenerative diseases increased expression of heat shock proteins prevents protein expression and aggregation protein disorder and aggregation by repairing proteins that have been damaged and animal evidence suggests that heat shock proteins may offer protection against neurodegenerative diseases uh heat shock proteins also moderate muscle atrophy findings from a small interventional study in rodents demonstrated that local heat application during immobilization decreased muscle attribute by 37 percent uh so they there's not a single animal model that shows that increased expression of heat shock proteins actually causes uh this longevity phenotype and this leak i don't know i haven't even looked at this is it a review maybe a review it's a review we're not looking at it because it's a review okay but in any case i what i decided to do is okay if increased heat shock proteins reduces mortality if it increases longevity then we should see in animal models where you increase the expression of heat shock proteins you should see a longevity phenotype because we actually see that with stuff like autophagy genes if you increase autophagy expression you're going to get a longevity phenotype sometimes in these particular cases
for heat shock proteins that's not the case look so over expression of heat shock protein 70 in mice is associated with growth retardation tumor formation and early death this paper showed if you increase the expression of heat shock proteins in these mice you actually kill them earlier they die earlier so contrary to what this she says here heat shock proteins actually cause these animals to die earlier well so that's interesting so what does that mean exactly well if you go look at the heatoc protein if you go look at the heat shock protein literature it's not that heat shock proteins are like protecting these animals and they're like making sure that they like you know live longer they're actually just preventing proteins from being misfolded they're just an adaptive response to damage why do you think that just increasing the expression is something that just responds to damage is necessarily going to produce a longevity phenotype and furthermore if you're doing sauna and you're inducing damage and you need heat shock proteins to compensate for it is that a good thing like how is that a good thing if you're inducing damage and you're expressing like repair enzymes and stuff you're causing damage that would be my way of looking at it as far as i can tell okay well so the only models the animal models that we have are showing that he shocked proteins actually cause a shorter life the only human studies that we have are seriously confounded and these confounding problems are basically overlooked they're basically overlooked by rhonda
patrick and Huberman whenever they interpret the research literature they they kind of ignore it there's no randomized controlled trial that shows that if you assign people to sonoverse not assigning them to sonic they live longer there's no literature like that but instead we only have this highly confounded observational literature yet um often these claims are made with this great amount of certainty and and sort of almost a zealousness on these podcasts that are listened to by millions of people well okay be that as it may so i decided to like fact check the last thing you talked about dinorphin and how dinorphin um is important for the expression of heat shock proteins so i looked in rhonda patrick's review and and she says that denorphin is an opioid that is generally responsible for the sensation of dysphoria a profound sense of unease or satisfaction dinorphin may also mediate the body's response to heat helping the body to cool heat activates neurons in the dorsal lateral peribrachial nucleus the expressed dinorphin the activation of this thermosensory pathway elicits heat defense responses in which the binding of dinorphone to kappa opioid receptors triggers cellular events that promote pain in distress the heat stress caused by sonoma pronounced dynorphin release which may be responsible for the general sense of discomfort experience from heat exposure so kubernetes says that dominorfin causes the expression of heat shock proteins i've never i don't see that anywhere here i don't see anywhere in this review that that's the case i googled it i couldn't find anything i wouldn't pubmed
i couldn't find anything if it's true that that dinorphin causes the upregulation heat shock proteins cool but i still couldn't even get this fact to work out but if if it does that's cool but if it does it's kind of irrelevant because the human data isn't good there's no good animal data the animal data that we have shows that animals die earlier so why do we peddle the story it's kind of simple all right it's like you say new things you say new exciting things you make people think that they're in the know like i'm learning this new stuff i'm in the like cutting edge of what everything is and then you make basically making people feel good about themselves you're basically flattering people's egos and so many of these people get basically like idolized because they're flattering lay people's egos to make them think that they're in the know and they they like they know more than other people or something about longevity and all this stuff but there's no evidence whatsoever that sauna actually causes these effects and in fact there's a new body of literature john speakman is is kind of a part of this he he published a paper i want to say it was in nature neuroscience or or maybe it's a nature metabolism what was it
sorry it was in nature aging and it's called body temperature not metabolic rate modulates lifespan that's our research highlight let's get to the actual paper itself sorry my mistake again it's in nature metabolism it's called body temperature is a more important modulator of lifespan than metabolic rate in two small animals and what this study found is actually if you keep the animals hotter over the entire course of their life that's not the same as acute intermittent heating to be sure it's not the same as sauna to be sure there's no question about that but among the evidence that we do have if you keep these animals hotter for their entire life as opposed to cooler they end up dying earlier so again we have multiple different lines of evidence the human evidence is not very clear that it gets rid of reverse causation the um the animal evidence of overexpressing heat shock proteins actually shows a reduced lifespan the animal evidence of keeping animals hot for their entire life shows the reduced lifespan whereas if you would get more heat shock proteins because they're hot most of the time you'd expect increased lifespan and then many of the mechanisms don't even make sense either for example the dinorphin mechanism i don't think as actually substantiated by the research literature so again the question is why are these claims repeatedly stated it's not a good thing to tell people
things that are not true so this is the the basic position i have on this so i don't know i would like for for things to be different but but they are what they are so if you like this video if you like my debunkings in general my commitment right now is to do four kind of positive videos quote unquote like four new things that people can learn about all sorts of different areas that i'm interested in to every one like debunking video and so i've done my four i'm doing my one debunking video and if you like these debunk videos cool if you like the positive videos as well check those out uh you can find me on instagram tick tock twitter at um kevin and bask avi and nbass you can also find me patreon at the same thing please donate because i need the money so so you send me the money um patreon if you do become a patron uh you can even i'll prioritize your questions of course i try to respond to as many comments as i can but i don't always get to everybody's comment i try to respond to your questions more um and of course if you're an upper tier patron you can um you know talk with me once a month about the various different things i'm reading about and thinking about and things that you might want to know more about yourself uh so yeah and then check out my website at thedietwars. com check out the diet wars dot com slot forward slash support dash me if you want to donate directly
as opposed to become a patron if you want to check out the podcast to get a the kevin bass show check out youtube at cabez philadelphia that's going to be my youtube channel and uh yeah so i hope you enjoyed it like comment subscribe and let me know what i can do better give me some feedback i would very much appreciate the feedback both positive and negative and of course i would probably prefer positive because i get a lot of negative i think it's just kind of the tendency of the internet but if i could also get some positive that would be cool too so let me know what i'm doing right as well as wrong so uh please do that and then you know check things out um see you guys in the next episode bye-bye
Transcript auto-generated by YouTube. Verbatim — duplicates intentionally preserved.
In this critique, Kevin Bass challenges some of the more confident claims made about sauna, longevity, heat shock proteins, and epidemiological evidence. The useful lesson is not cynicism. It is precision. Good science gives the practice more integrity, not less.
Much of the popular sauna protocols conversation leans on population studies. These studies can reveal meaningful associations, especially around cardiovascular outcomes. They cannot, by themselves, prove that sauna directly causes longer life.
That distinction matters. People who use saunas regularly may also differ in income, health behavior, access to care, social rhythms, and the benefits of recovery habits. Careful interpretation protects the practice from becoming overpromised.
Heat shock proteins are often presented as the clean mechanism behind the science of sauna benefits. The biology is more complex. Heat stress activates protective pathways, but translating that activation into broad claims about lifespan requires more evidence than a simple chain of cause and effect.
A grounded approach names the mechanism without pretending it explains everything. Heat is a stressor. The body responds. Some responses may be beneficial in the right context, dose, and person.
"He overstates the strength of the epidemiological evidence." — Kevin Bass
Questioning overreach does not dismiss the science of sauna. Heat can support relaxation, circulation, perceived recovery, and a deliberate pause from stimulation. Those are not small things.
The mature position is neither hype nor rejection. It is to use sauna because it fits a broader recovery protocol, while staying honest about what the current evidence can and cannot claim.
Wellness loses authority when every practice is made to sound like a cure-all. The better standard is quieter and stronger: clear benefits, clear limits, and room for the science to evolve.
That is especially important for contrast therapy. Cold and heat are powerful because they are simple stressors. They deserve protocols built on dose, context, and respect for individual response.
A practice does not become weaker when we speak about it carefully. It becomes more trustworthy.
Use sauna as part of a recovery system, not as a standalone promise of longevity.
Be cautious with claims built only from association studies or simplified mechanisms.
Track your own response: sleep, relaxation, training recovery, hydration, and heat tolerance.
