The Science Behind Sauna Therapy: Unlocking Health and Longevity
The cold plunge case is mostly anecdotal. Sauna is a different story — decades of cohort data on cardiovascular risk, growth hormone, immune resilience, and endurance, with mechanisms that hold up.
Video·Thomas DeLauer·12 min read·June 2026
Sauna sits at the centre of a lot of wellness noise. The literature, it turns out, is quieter and more interesting than the hype.
The cardiovascular case
A simple question deserves a clear answer. Does sauna live up to the hype, or is it anecdote dressed up as science? The wellness space has a habit of bundling every heat or cold ritual together, then asking us to take the claims on faith.
Cold plunging draws much of that attention. The evidence base there is thinner than the conversation suggests — mostly anecdotal, mostly mental, with real but modest physiological support behind it. Sauna is a different story. The literature is unusually consistent, and it has been accumulating for decades.
I wanted to make sure I wasn't drinking my own Kool-Aid, because my anecdotal experience is amazing.
Step into a sauna and the body responds the way it responds to exercise. The heart rate climbs, breathing deepens, vessels open. The work is genuine, even though you are sitting still. The same systems that adapt to a hard run begin to adapt here, in stillness rather than in motion.
A study published in JAMA followed more than 2,300 Finnish participants for an average of 20.7 years. The researchers tracked sudden cardiac death, coronary heart disease, cardiovascular disease, and all-cause mortality. The dataset is one of the most rigorous we have on any wellness practice.
Compared with a single weekly session, two to three sessions per week were linked to a 22% reduction in sudden cardiac death. Four to seven sessions per week were linked to a 63% reduction. The other cardiovascular categories moved in the same direction, with similar magnitude. This is dose-response data on a scale most interventions never reach.
Effects of this magnitude are uncommon in cardiovascular research. Most pharmaceutical interventions in the same space measure their benefit in single-digit percentages. A behavioural ritual producing this kind of separation in mortality outcomes is, on its own, worth pausing over.
Mechanism work in Mayo Clinic Proceedings helps explain why. Sauna heat triggers endothelial dilation — the inner lining of the blood vessels opens, the arteries widen, blood pressure drops. The heart pushes against less back-pressure, which over time translates into a calmer, more durable cardiovascular system.
The same paper points to reductions in systemic inflammation and oxidative stress. When inflammation drops, the cascade that turns arterial plaque into foam cells loses momentum. Less inflammation means fewer unstable plaques, and fewer unstable plaques means lower risk of the events that end lives suddenly.
Arterial stiffness declines as well. As the endothelial cells lining the arteries lose function, vessels become rigid, and the heart works harder to move blood through them. Sauna appears to slow that drift, keeping the arteries pliable and the system responsive.
The cardiovascular case is not a hopeful inference. It is one of the better-documented effects in the recovery literature, supported by long-horizon cohort data and a coherent mechanistic story. For a ritual measured in minutes per week, the return on attention is rare.
is a sauna really worth the hype I feel like we live in an era now where everything is sensationalized it's so difficult to ascertain if something's legit or not I did a similar video to this on cold plunging because is cold plunging worth the hype like people tout all these crazy benefits but when we Dove deep into it there's not much literature to back it up all of it seems to be anecdotal or just mental which counts for a lot don't get me wrong like mental fortitude and building that resilience there infinite potential with that but is sauna the same thing like if I talk about Asana or I see someone else talk about Asana people just really jump on them saying you're a tinfoil hat wearing weirdo because you think saunas are cool well when I looked at the literature it was pretty crazy I'm a big sauna guy and I wanted to make sure I wasn't drinking my own Kool-Aid because my anecdotal experience is amazing anyhow the first one is simple cardiovascular health right with that when you jump in a sauna you feel like you're working out like
realistically your heart is pumping you're breathing heavily you're vasodilated it feels like you're working out like it feels like you're running when you jump in a cold plunge it's hard but you don't feel like you're working out you just feel like you're suffering like I feel like I'm working out Nicole in a sauna now with this there's data there's a study published in Jama like a huge study took a look at over 2300 finished participants and attract them for over 20 years 20.7 years okay and it looked at their sudden cardiac disease risk like their sudden cardiac death they also looked at just regular coronary heart disease regular cardiovascular disease risk and all-cause mortality what they found is that compared to one time per week sauna going in Asana for two to three times per week led to a 22 percent decrease in sudden cardiac death and about the same decrease in the other categories too but in those that went in Asana four to seven days per week there was a 63
percent less risk of sudden cardiac death and again very similar percentages in the other groups as well okay that is very very strong data so no matter who you are from a General Health cardiovascular perspective it makes sense but we have to understand mechanisms to really get excited about it so what's happening in your body well with that there's a study that was published in the Mayo Clinic proceedings but we still need to do more work like mechanisms are tough the first thing they notice is that okay there's a huge vasodilation effect so you end up having what's called endothelial dilation which is going to decrease the blood pressure and that just takes the pressure off the heart the back pressure so the heart doesn't have to work as hard because there's less pressure that it's pushing against now additionally there's other things going on you also have reductions in inflammation and reductions in reactive oxygen species oxidative stress which of course put pressure on the entire body not to mention the cardiovascular system so when you reduce the inflammation then you have less risk of arterial plaque turning into these foam cells which can ultimately cause an
issue and lastly there's a decrease in arterial stiffness now this is a classic issue with cardiovascular disease where the arteries become stiff because the vascular life the cells the endothelial cells actually die and become dysfunctional and basically the heart is now pumping blood through dysfunctional stiff arteries which is hard on the whole system right so we have that now let's talk about some more fun stuff though growth hormone now this unfortunately is where people end up getting absolutely hammered online and sometimes it's well deserved because I've seen people do it people talk about Asana and they say it's these exponential benefits by because there's exponential increases in growth hormone and it's going to make you put on gobs of muscle just by drinking lemonade and the reality is that that's not how it works but the literature is pretty darn strong with growth hormone so let's look at it there's a study published in experimental gerontology which sounds like kind of a scary thing it sounds like they're doing experiments on old
people but anyway what they're doing in this study is they took a look at not necessarily old people but they took a look at people that went into Asana for different bouts of time so in this case they did two 20-minute bouts at 80 degrees Celsius with a 30 minute break in between okay so lower temperature for 20 minutes they found that doing this increased growth hormone pulses 2X then they found that going in for 15 minutes slightly shorter bout at a higher temperature 100 degrees Celsius with a 30 minute Gap in between these two sessions led to a 5x increase in growth hormone and this lasted for a few hours after the session so we now see that higher heat seems to elicit more of a growth hormone response because probably it's changing intracranial pressure is probably having an impact on the brain that way so it's changing how you actually secrete growth hormone okay well what's really interesting is then they said okay what happens if you do this twice a day for one hour like one
hour sessions in the morning and at night for seven days kind of unrealistic for most people with time but there was a 16x increase in growth hormone which ultimately demonstrates that if you're consistent not necessarily doing two times per day all the time but consistently hitting a sauna maybe in the morning maybe in the evening booking it that's going to have a huge impact on growth hormone that doesn't mean you're going to build a bunch of muscle no it probably means realistically that you might prevent some sarcopenia some muscle breakdown if your protein intake is high enough it will probably help support that but also it just helps stimulate repair and Recovery because your immune system also relies a lot on growth hormone as well so you just got to pay attention to all this it's a huge piece but it doesn't deserve us shouting from the rooftops that you're going to magically become Jay color I also put a link down below for the sauna that I use at home it's a company called Redwood Outdoors if you're trying to get a classier sauna that looks good in your backyard that's really good quality wood that's not going to be like I'll tell you realistically like the big friction that I have with my wife is my wife is
like I don't want to have a big ugly sauna in our backyard but most of them in a barrel they just don't look that good but the nice thing about redwood Outdoors is kind of makes the whole family happy like it's beautiful it looks really nice it smells amazing it's classy and they have a bunch of different varieties whether it's cubes whether it's barrels whatever so I did put a link down below and that link will get you 250 bucks off if you want to try out a sauna and people do ask me all the time I know it's not necessarily in the budget for a lot of people I totally respect that and totally get that and I think there's Alternatives like if you need an infrared or you need to use a sauna blanket to start like by all means or take a hot bath like that can get you a similar effect but having a sauna is a really nice thing if it's something that you really want to invest in and personally I think it's worth the investment no matter what company you use I just think Redwood Outdoors does it really well so that link is down below I think you'll really enjoy what you see there on their website with a different variety that they have the next one is an interesting one but the data is so strong and that's on the
immune system there's a study that was published in the European Journal of epidemiology it took a look at over 1900 participants for 25 years okay and they looked at respiratory infections they looked at hospitalizations with respiratory issues just respiratory illness in general they found that using a sauna 2 to three times per week decrease the risk of respiratory illness by 27 percent okay I'm kind of a Believer here but it found that if you went up to four times per week the results were even crazier at four times per week not even more just straight up four 41 decrease risk of respiratory illness or hospitalization from respiratory illness so potentially decreasing intensity of an illness and even decreasing the ability to contract it in the first place but how is this working once again we get into mechanisms like we don't entirely know but we have seen some literature explaining what might be going on so there was a study published in medical microbiology and there's
these things called antigen presenting cells and what they do is they help sort of find the pathogens and heat shock proteins which are increased when we are in Asana what happens is these heat shock proteins help kind of refine these apcs okay these antigen presenting cells and what they do is they if you had a laser-guided missile it basically refines your laser to make it X percent more accurate so you now have a more defined accurate laser to find a pathogen and neutralize it but heat shot proteins themselves are a chaperoning protein which means they help refine a lot of different things and make things more efficient including the immune system but they also help sound the alarms so it's like having a bunch of reconnaissance planes flying around that sound alarms if something is out of place or shouldn't be there so it lets the body know then additionally heat shock proteins can modulate what are called toll-like receptors and these
toll-like receptors can help with the timing of things so imagine you have this laser guided missile that works super well and you need to shoot it at a Target but you need to wait for the enemy to actually be there like what good is shooting and neutralizing a Target Zone without the actual Target enemy there right so the timing becomes very important so these whole like receptors kind of help facilitate that so the mediation of these tlrs from the heat shock proteins really could be one of the reasons again we don't know this is mechanistic Theory but we have the larger scale data know that something's going on here but then one of the big reasons that I like to sauna is because of the muscle preservation potential I say potential because we never know for sure but the data is strong there's a study published in Frontiers physiology had subjects to a 60-minute whole body sauna session or a single leg sauna session like where they just basically isolated their leg and put it in high heat and they did muscle biopsy to see like what's changing they actually took a chunk of the muscle and looked at it they found that whole body sauna had
huge impacts over just the single leg so it wasn't it was systemic it wasn't just isolated in the leg and what they ended up discovering is that there was an increase in What's called the phosphorylation or activation in human terms of the akt and mtor pathway what this means is that the environment in which which muscle protein synthesis occurs and muscle growth that entire environment was changed and it was tilted more towards a muscle building state it doesn't mean that you're going to build a bunch of muscle but it means that you are in theory putting yourself in a more opportune state to build muscle when you consume protein and have proper stimulus surrounding this could the sauna be the stimulus itself probably not but I do think that using a sauna post workout can increase the effect of the protein that you get as a result of the stimulus and another big reason from a performance standpoint there's a lot of data backing up running walking hiking just aerobic fitness in
general and even though I look like a meathead I would probably consider myself more of a runner than a lifter realistically and when you look at the data here it's quite strong there's a study published in the journal science and medicine and Sport took a look at Runners and I had these Runners do three weeks of their normal running routine then it had them do three weeks of their running routine alongside 30-minute sauna sessions what they found is that the sauna group only had a 32 percent increase in their time to exhaustion so they were able to go for 32 percent longer before getting tired which resulted in a 1.9 increase or Improvement I should say in their time trial time so they actually got faster and they went for longer they had a 7.1 percent increase in their red blood cell volume that's like I don't know it's not quite the same but it's like blood doping I mean that's crazy that is a huge Improvement in the ability to carry oxygen so this has huge benefits for maybe uh well exercise obviously but
maybe training at altitude like or if you're going to be doing some kind of mountaineering trip and you need to increase RBC count that's huge but let's talk about real people for a second too people that maybe aren't athletes this study was published in the American Journal of physiology took a look at 47 individuals okay and it had them either do exercise or exercise plus SATA they found that the exercise plus sauna group ended up having larger improvements in their overall respiratory Fitness their aerobic capacity and aerobic fitness but they also had a decrease in blood pressure so the heart was literally working less hard to support more activity to support more threshold and support more intensity so is sauna worth the hype yeah it is and if people want to rope cold plunging together with sauna that's doing us a disservice because saunas have literature behind them coal plunges just work because they might work I they do they don't there's nothing to really back it up but you're not a tin foil hat wearing weirdo if you
sit in a sauna the literature is there I'll see you tomorrow
Transcript auto-generated by YouTube. Verbatim — duplicates intentionally preserved.
Growth hormone and repair
Growth hormone is where the sauna conversation tends to go off the rails. The promise of effortless muscle gain belongs to advertising, not biology. The actual data is more interesting than the marketing, and worth a careful read.
It doesn't deserve us shouting from the rooftops that you're going to magically become Jay color.
A study in Experimental Gerontology measured the growth hormone response to different sauna protocols. Two 20-minute sessions at 80°C, separated by a 30-minute break, doubled growth hormone pulses. Two 15-minute sessions at the higher temperature of 100°C produced a fivefold increase, sustained for hours after the participants stepped out. The pattern is unmistakable.
Higher temperatures appear to shift secretion in a way lower temperatures do not. One proposed mechanism involves changes in intracranial pressure that alter how the pituitary releases growth hormone, leading to sharper repair signalling and steadier recovery. The mechanism is still being worked out. The downstream signal is clear.
The most extreme protocol in the literature involved one-hour sessions, twice a day, for seven consecutive days. Growth hormone rose sixteenfold. Few people will replicate that schedule, and few should try, but the trajectory tells us what consistency can do over time.
Translated into something practical, this is not about putting on muscle from heat alone. The realistic frame is protection — preserving the lean mass you already have. Sarcopenia, the slow loss of muscle with age, is one of the strongest predictors of frailty and mortality, and growth hormone is part of the system that holds it at bay.
Sarcopenia is one of the quieter ways ageing takes its toll. Strength fades. Stability follows. The decline rarely registers in the moment, but adds up over decades into a real change in capacity. A practice that supports the hormonal scaffolding behind muscle maintenance is not cosmetic — it is foundational.
Repair benefits from the same pathway. Tissues regenerate more efficiently when growth hormone is in circulation, which matters whether the load is a hard training session or the slower wear of daily life. Recovery is essential, and the hormonal terrain shapes how completely it happens.
Immune function also leans on growth hormone. The body's defence systems share resources with its repair systems, and a hormonal environment that supports one tends to support the other. Resilience is rarely the product of a single mechanism. It is the compounding of several quiet ones.
A reasonable expectation from a consistent sauna practice is preserved lean mass, faster recovery, and steadier immune performance. None of that turns anyone into a bodybuilder. All of it changes how the body holds up over the decades, which is the question worth asking in the first place.
Immune resilience
The immune effect of sauna is one of the more striking findings in the literature. A study in the European Journal of Epidemiology tracked more than 1,900 participants for 25 years, looking specifically at respiratory infections, hospitalisations, and overall respiratory illness. The scale and duration give the result a weight that shorter trials cannot manufacture.
Two to three sessions per week were associated with a 27% reduction in respiratory illness. Four or more sessions per week pushed that figure to a 41% reduction in both incidence and hospitalisation. The signal holds across a long time horizon and a large population, which is rare for any wellness intervention. The protocol is also remarkably simple to implement.
Mechanism work in Medical Microbiology offers a coherent explanation for the outcome data. Heat shock proteins, upregulated by the thermal stress of sauna, support the antigen-presenting cells responsible for identifying pathogens. Sharper identification means a faster, more accurate immune response — in plain terms, faster recovery when something does take hold.
Heat shock proteins function as chaperones. They guide other proteins into the correct shape, hold them steady under stress, and refine the systems they touch. The fitting metaphor is a guidance upgrade — the body already had its weapons, and the chaperones tighten the aim, building resilience without strain.
They also modulate toll-like receptors, which govern when the immune response fires. Timing is half the battle. An accurate strike at the wrong moment is wasted, and an early strike at a false target costs the body energy it could have saved. The chaperones tune both the target and the moment.
This is not amplification. It is refinement. A sharper, better-timed immune response is not a louder one — it is a quieter one, because it does the work it needs to do without overshooting. The body that overreacts is often the body that struggles.
The mechanistic picture is partial. The cohort data is not. When mechanism and outcome point in the same direction, the practice deserves serious attention, even while the finer details continue to be mapped.
What you feel from this in daily life is harder to measure and easier to recognise. Fewer days lost to lingering colds. Faster bounce-back when something does take hold. The kind of clarity that comes from a body that is not constantly defending itself.
Worth noting, too, that the immune benefits do not require extreme heat or extreme duration. The same protocols that drive cardiovascular adaptation drive immune refinement, which makes the ritual unusually efficient across systems. One practice. Several systems. All compounding.
Muscle preservation and endurance
The muscle data is where sauna becomes interesting for people training seriously. A study in Frontiers in Physiology compared whole-body sauna exposure with single-leg exposure, using muscle biopsies to see what changed inside the tissue. The result was clear and informative.
Whole-body sauna activated the Akt/mTOR pathway systemically, the cellular signalling system that governs muscle protein synthesis. Single-leg exposure did not. The effect is not local heat doing something to the local tissue — it is the body shifting into a more favourable state for repair and growth, signalled across systems.
This is worth framing carefully. Sauna is not the stimulus that builds muscle. Resistance training does that, and protein gives the tissue what it needs to rebuild. What sauna does is tilt the hormonal and signalling terrain so that the inputs you provide land more completely.
The implication for serious training is concrete. A sauna session after a workout pairs the muscle-building stimulus you just created with a hormonal environment that supports the rebuild. The work was already done. The terrain simply receives it better.
For athletes, the endurance findings are stronger still. A study in the Journal of Science and Medicine in Sport followed runners through three weeks of their normal training, then three weeks of the same training paired with 30-minute sauna sessions. Time to exhaustion increased by 32%. Time trial performance improved by 1.9%. Red blood cell volume rose by 7.1%.
A 7% gain in red blood cell volume is significant. More red blood cells means more oxygen delivery, more oxygen delivery means more sustained output, and more sustained output translates directly into performance. It is the kind of adaptation people seek with altitude camps. Sauna delivers a fraction of it at home.
Non-athletes benefit on a different axis. A study in the American Journal of Physiology tested exercise alone against exercise paired with sauna in 47 individuals. The combined group showed larger improvements in aerobic capacity and a meaningful reduction in blood pressure compared with exercise alone. The heart did more work and met less resistance at the same time.
The lesson generalises. Sauna does not replace movement. It compounds it. The combination outperforms either practice on its own, which is how most durable habits work — not as substitutes, but as layered practices that reinforce each other.
So, the original question. Is sauna worth the hype? On balance, yes. The literature is unusually consistent across cardiovascular health, growth hormone, immune function, and performance, and the mechanisms supporting those outcomes are increasingly well-mapped.
You're not a tin foil hat wearing weirdo if you sit in a sauna. The literature is there.
Roping sauna in with cold plunge does the evidence a disservice. The cold plunge case is mostly anecdotal and mostly mental, which is not nothing, but it is not what sauna offers. Conflating the two reduces a strong body of work to the level of the weaker one. They deserve to be evaluated separately.
The framing that matters most: sauna is a ritual, not a hack. A hack implies a shortcut, and shortcuts rarely compound. Rituals compound by definition, because they are practised regularly and held lightly, allowed to do their work over time.
Three or four sessions a week, enough heat to feel the work. The same consistency you would bring to any practice that earns its place. The literature is there, the protocol is simple. The return is measured in decades.
