Do the benefits claimed by sauna users REALLY live up to the hype
The following is the transcript of a video produced by Thomas DeLauer. This video offers a thorough but succinct discussion of the benefits of regular sauna usage. Mr. DeLauer cuts through the hype and medical jargon in plain language
But there is TOO much information to assimilate in the few minutes of this video. (Not to mention all the visual images and statistics). For that reason, The Great Out There blog offers this written transcript of the video (with edits only for grammar.) I invite you to watch the video, then READ the transcript to assimilate all this important information. In addition, following the transcript, please also see several comments that other viewers have added in response to this staggering collection of data.
Is a sauna really worth the hype? Are there REAL health benefits?
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 on whether cold plunging is worth the hype? People tout all these crazy benefits. But when we dove deep into cold plunging there's not much literature to back it up. All the benefits seem to be anecdotal or just mental. Don't get me wrong, increasing mental fortitude and building resilience has infinite potential.
If I talk about a sauna or I see someone else talk about saunas, 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.
The first sauna benefit is simple: cardiovascular health.
When you jump in a sauna, you feel like you're working out. Realistically your heart is pumping, you're breathing heavily, you're vasodilated. It feels like you're working out. 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. But I feel like I'm working out in a sauna.
There is test data related to the cardiovascular benefits of sauna usage. A study published in the Journal of the American Medical Association looked at over 2,300 Finnish participants and tracked them for over 20 years. The study looked at sudden cardiac disease risk and sudden cardiac deaths. The study also looked at coronary heart disease, cardiovascular disease risk, and all-cause mortality. The study compared sauna sessions one time per week, then increasing the sauna to 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. Increasing the sauna to four to seven days per week resulted in a 63-percent decrease in sudden cardiac death and very similar percentages in the other groups as well!
That is VERY, very strong data. From a general health and cardiovascular perspective, sauna usage makes sense. But we have to understand bio-mechanisms to really get excited about this.
We need to better understand the causes for the sauna study results.
Another study that was published in the Mayo Clinic Proceedings. The first thing this study noted was the huge vasodilation effect of sauna usage. You experience endothelial dilation which decreases the blood pressure. The heart doesn't have to work as hard because there's less arterial pressure.
Additionally, you also have reductions in inflammation and oxidative stress. These put pressure on the entire body, not only the cardiovascular system. When you reduce inflammation, you have less risk of arterial plaque turning into foam cells, which can ultimately cause an issue.
Lastly the sauna contributes to a decrease in arterial stiffness. Cardiovascular disease results when the arteries become stiff because the vascular cells, the endothelial cells, actually die and become dysfunctional. The heart is now pumping blood through dysfunctional (restrictive) stiff arteries, which is hard on the whole system. (Note that the Mayo study included many more health benefits of sauna usage not mentioned in this video.)
How the sauna affects human growth hormones.
Growth hormones are a topic where people end up getting absolutely hammered online - and sometimes it's well deserved. People talk about their sauna experiences, their exponential benefits, including exponential increases in growth hormone. The hype is that the sauna (alone, without exercise) is going to make you put on gobs of muscle.
The reality is that that's not how it works. BUT the literature is pretty darn strong concerning growth hormone. In a study published in Experimental Gerontology (which included not only old people, but a range of age groups), the participants did two 20-minute sauna sessions at 80 degrees Celsius (that is, 176 degrees Fahrenheit) with a 30-minute break in between. The results were increased growth hormone pulses 2X (that is, a 200% increase). Then the study found that using the sauna for 15-minutes – a slightly shorter session but at a higher temperature of 100 degrees Celsius (that is, 212 degrees Fahrenheit) with a 30-minute gap in between these two sessions - led to a 5X (that is, 500%) increase in
growth hormone. This increase lasted for a few hours after the session.
We now see that higher heat seems to elicit more of a growth hormone response. The theory is that heat changes intracranial pressure, which impacts the brain and changes the secretion of growth hormones.
Then they studied sauna usage twice a day for one hour. That is, one-hour sessions in the morning and at night for seven days. (This might not be realistic for most people with time constraints.) The results were a 16X increase in growth hormone. All this ultimately demonstrates that if you're consistent, maybe alternating daily session in the morning and evening, that's going to have a huge impact on growth hormone production.
That doesn't mean you're going to build a bunch of muscle. No, it probably means (realistically) that you might prevent some sarcopenia – that is, muscle breakdown. If your protein intake is high enough, sauna usage will probably help prevent muscle breakdown. But the sauna also helps stimulate repair and recovery because your immune system relies a lot on growth hormones. These results on growth hormones should get your attention! This is a HUGE benefit! (Less muscle breakdown; better recovery.)
The sauna and immune system benefits.
The next study shows strong data related to the benefits of the sauna to the immune system. The study in the European Journal of Epidemiology involved over 1900 participants for a period of 25 years. They examined respiratory infections and hospitalizations due to respiratory issues. The report was that using a sauna two to three times per week decreased the risk of respiratory illness by 27 percent.
The study also reported that if you increased sauna sessions to four times per week the results were even crazier. At four times per week the participants experienced a 41 percent decreased risk of respiratory illness or hospitalization. That is potentially decreasing BOTH the likelihood of contracting a respiratory illness AND the severity of an illness.
How does this work? How does the sauna affect bio-mechanisms?
Another study published in Medical Microbiology and Immunology examined antigen presenting cells, or APCs. These antigen presenting cells target pathogens. At the same time, heat shock proteins are increased when we are in the sauna. And heat shock proteins help refine these APCs.
Compare antigen presenting cells to a laser-guided missile. The analogy is fine-tuning the aim of the laser to make it more accurate, helping to target a pathogen and neutralize it. Heat shock proteins are called chaperoning proteins, which means they help enhance the APCs. The result is a more efficient immune system. But APCs also help sound the alarms, alerting the immune system.
Additionally, heat shock proteins can modulate what are called toll-like receptors. These TLRs can help with the timing of immune functions. Imagine you have this laser guided missile that is very accurate – but you need to first identify the target. You can’t shoot until the target is located and that is why timing is important. TLRs can affect the timing, and their functions seems to be enhanced by increased heat shock proteins. This is bio-mechanical theory, but we have larger scale data that shows correlation to sauna usage.
The sauna and muscle preservation.
One of the big reasons that I like the sauna is because of the muscle preservation potential. I say “potential” because we never know for sure, but the data is strong. A study published in Frontiers Physiology involved subjects who compared a 60-minute whole body sauna session to a single leg sauna session, where they only isolated their leg in high heat. They did muscle biopsies to compare the difference. That is, the researchers examined the muscle fibers. They found that whole body sauna had huge impacts over just the single leg treatment. It was systemic – the benefits were not just isolated in the leg.
The study reported that there was an increase in what's called the phosphorylation, or activation of the AKT and MTOR pathway. This means that the sauna affected the entire environment in which muscle protein synthesis occurs and muscle growth was changed. It was tilted more towards a muscle building state. This doesn't mean that you're going to build a bunch of muscle, but it means that you are putting your body in a more opportune state to build muscle when you consume protein and induce the proper stimulus. Could the sauna be the stimulus itself? Probably not, but I do think that the stimulus of the sauna post workout can increase the effects of protein intake.
The sauna and athletic performance.
From a performance standpoint, there's a lot of data backing up enhancements to running, walking, hiking, and aerobic fitness in general. A study published in The Journal of Science and Medicine in Sport followed runners. These runners completed three weeks of their normal running routine. Then it had them repeat another three weeks of their running routine, followed by 30-minute sauna sessions.
The study reported that the sauna group had a 32 percent increase in their time to exhaustion. They were able to run 32 percent LONGER before getting tired. This added exercise also resulted in a 1.9 percent improvement in their time trial time. They actually got faster, and they ran longer. The participants also had a 7.1 percent increase in their red blood cell volume. That'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.
This has huge benefits for exercise, obviously. It’s comparable to the results from training at altitude. If you're going to be doing some kind of mountaineering trip and you need to increase the RBC count. But this applies to all people, including average people that maybe aren't athletes. Another study was published in the American Journal of Physiology that included 47 individuals. In this study, some participants only exercised, while others combined exercise and sauna sessions. The results showed that the exercise plus sauna group showed larger improvements in their overall respiratory fitness, their aerobic capacity, and aerobic fitness. They also had a decrease in blood pressure. This means the heart was literally working less to support more activity, to support a higher threshold at a higher intensity.
So, is sauna worth the hype? Are there REAL documented health benefits?
YES! It is a disservice to connect the hype surrounding cold plunging together with the scientific benefits of sauna usage. Saunas have much scientific literature supporting statistical benefits. Cold plunges might work - I think they do - but there is nothing to really back it up. Conclusion: you're not a tin foil hat wearing weirdo if you sit in a sauna. The study literature is there.
The Great Out There is pleased to provide this information summarizing the many benefits of saunas. We have enjoyed saunas for years, including many sub-zero nights in the far North. We have found nothing erases the soreness and stiffness of a hard day’s work – or the exertion of sled dog racing – like a hot sauna, followed by a cold plunge or shower or roll in the snow! Stay tuned for more insights into the benefits of the sauna.