Are there sauna benefits for those interested in longevity and lifespan extension?

People in Finland live on average 3.3 years longer than those in the United States and, while correlation doesn’t equal causation, almost every Finn has access to a sauna either at home or nearby. Many of them sauna bathe at least once a week.

Could a longer lifespan be one of the major health benefits of frequent sauna use?

Both cold and heat therapy have been suggested as possible life extension interventions and, while I was unimpressed with the lack of solid research behind the idea of cryotherapy for longevity (especially given how many “biohackers” promote it as a cure-all), my investigation into sauna and heat therapy has been decidedly more interesting.

While I was researching the impact of heat therapy on longevity I had several questions I wanted answered:

• Is the evidence that heat therapy can improve longevity better than the evidence for cold therapy?
• Is there evidence heat therapy actually improves lifespan and not just health span?
• What type of heat therapy has the best evidence for health benefits?
• Is sauna dangerous for people with heart conditions?
• Is sauna safe for older people and children?

Luckily, it seems like there are pretty good answers to all of these questions and I’ll touch on all of them below. 

Use the links in the table of contents to hop around to whichever answer most interests you!

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The science behind heat therapy for longevity

If you’ve read my previous deep-dive into the science behind cold therapy for longevity, you’ll know I walked away from that article fairly pessimistic about the practice. 

For something so popular in the biohacking and life extension communities as cold therapy, it seemed to me it lacked sufficient research to prove positive health and longevity benefits.

Well, not so with heat therapy and life extension.

In addition to several meta-analyses, there are another dozen or so systematic reviews covering all of the research into heat therapy, the heat shock response, and heat exposure’s impact on longevity and health.

Heat therapy and the body’s response to heat exposure has been studied for decades, with some of the most seminal research having been done in the 60s and 70s. Not only is there more research into heat exposure, the mechanisms by which it might improve health and extend lifespan seem to be better understood than with cold exposure.

Important pioneering research into heat exposure was done in both fruit flies and roundworms, both of which found that acute heat exposure activates molecules within cells called heat shock proteins.

These proteins appear to be part of a cell’s response to stress, typically called the heat shock response. When activated, they move to express certain genes related to repair and cleanup of damaged organelles. These genes, including FOXO3, direct more of the cell’s resources to be used for autophagy and apoptosis.

These two processes, the first literally meaning “self eating,” and the second referred to as “programmed cell death,” help a cell to recycle damaged organelles and replace them with fresh, healthy ones, or for the body to do the same for entire cells that are malfunctioning.

As we discussed in our article on theories for why we age, as well as our discussion on intermittent fasting, autophagy and apoptosis play crucial roles in the body’s repair pathways, and seem to be important for life extension and general health span. In fact, almost every study in animals showing lifespan extension seems to rely on this repair pathway.

So the fact that the heat shock response and heat therapy generally seems to fit so well into the existing body of research on life extension is promising, at the very least.

But does this theory translate to actual longevity results?

Maybe!

Sauna benefits for longevity

Animal studies of intermittent, but not continuous, heat exposure generally tend to show health and life extension benefits.

For instance in fruit flies, the over-expression of heat shock proteins increased average lifespan by 30%.

In roundworms, according to a 2022 review, “While persistent heat stress is detrimental to nematode survival, either intermittent heat shock or mild hormetic heat shock also extends longevity via [heat shock protein 1] activation.”

Also in roundworms, if they are exposed to heat stress early in life they seem to live longer.

Mice injected with heat shock proteins have increased lifespans.

Additionally, ant queens have a 5x increased lifespan compared to non-reproductive ant females and the queens show an, “elevated expression of heat shock response (HSR) genes in the absence of heat stress and enhanced survival with heat stress.”

Human studies on the benefits of sauna have been similarly promising (I have to remind myself, as I sit writing this in my non-air-conditioned house during the summer…).

For instance, a 2018 systematic review of 13 studies on dry sauna use found that most of them reported beneficial health effects, including improved cardiovascular health, mood, pain tolerance, and lung function. And, of the 13 studies, “Only one small study (n = 10) reported an adverse health outcome of disrupted male spermatogenesis, demonstrated to be reversible when ceasing sauna activity.”

A more recent 2023 review concluded that frequent sauna bathing appears to reduce blood pressure, lower inflammation, and improve results of pneumonia, cardiovascular disease, and even lowers mortality risk.

A 2024 review was even more forceful, claiming: 

“The Finnish saunas have the most consistent and robust evidence regarding health benefits and they have been shown to decrease the risk of health outcomes such as hypertension, cardiovascular disease, thromboembolism, dementia, and respiratory conditions; may improve the severity of musculoskeletal disorders, COVID-19, headache and flu, while also improving mental well-being, sleep, and longevity.”

The advantages of sauna also seem to include everything from improved cardio-respiratory fitness, to improved muscle strength and bone mass, to reduced risk for dementia and Alzheimer’s.

And while this is all well-and-good for improving healthspan, might heat therapy improve lifespan as well?

There’s some promising human research here, as well.

Several population studies (which, as observational studies and not randomized controlled trials, can only ever show correlation, not causation) have found frequent sauna bathing is associated with lower all-cause mortality risk.

This includes two different studies (one from 2015 and another from 2022) of 2,000+ middle-aged Finnish men, and a 2019 review finding sauna bathing was protective against sudden cardiac death.

And sauna health benefits seem to be especially valuable for people with high blood pressure, and the poor, both of whom seem to live longer when doing regular sauna baths.

And the good news is most of these heat therapy benefits seem to hold across age and gender.

For instance, both young and middle aged-aged individuals, males and females, showed similar vascular responses to sauna heat stress. And, “Sauna was well tolerated and posed no health risks to healthy people from childhood to old age.”

It even seems safe (and possibly beneficial) for infants in short doses. But be careful to keep those doses short (5-10 minutes maximum) as children can’t sweat as well as adults to regulate their body temperature.

Interestingly, even infrared (or “waon”) sauna seems to share many of these benefits.

Infrared sauna benefits

One of the benefits of infrared sauna is improved cardiovascular health. For instance, a 2018 meta analysis found, “exposure to an infrared sauna bath in 60°C for 15 minutes, followed by a 30‐minute rest in warm environment, five times a week for 2 to 4 weeks” was associated with significant cardiovascular health improvements.

A 2021 review found dozens of positive studies on waon therapy for health, linking it to benefits ranging from improved exercise tolerance, to improved vascular function, better cardiac biomarkers, and even faster healing of skin ulcers.

But of course, no one therapy is a cure-all, and there are some risks to consider with sauna bathing and other types of heat therapy for longevity.

The risks of sauna

First off, heatstroke can kill.

And heatstroke in sauna has been known to kill, albeit rarely.

For instance a 2021 case study of two different cases, a 77 year old man and a 73 year old woman, found that in each case existing heart conditions caused them to pass out in the sauna, where they were each bathing alone, leading to their deaths (Note: don’t read that linked study if you are grossed out easily and if descriptions of partially mummified corpses found in saunas makes you squeamish).

That study did conclude however, “It should be mentioned that without this preexisting hypertensive cardiovascular disease, circulatory decompensation in the sauna might not have occurred in any of the cases.” Meaning those people may not have fainted and died in the first place if they hadn’t already had pre-existing heart disease.

Several types of cardiovascular disease seem to increase the risk for fainting and/or death in the sauna.

A 2001 review found that:

“Contraindications to sauna bathing include unstable angina pectoris, recent myocardial infarction, and severe aortic stenosis. Sauna bathing is safe, however, for most people with coronary heart disease with stable angina pectoris or old myocardial infarction. Very few acute myocardial infarctions and sudden deaths occur in saunas, but alcohol consumption during sauna bathing increases the risk of hypotension, arrhythmia, and sudden death, and should be avoided.” 

That last bit about alcohol is especially important because, as a 1988 review on alcohol and sauna use found:

“Ingestion of large amounts of alcohol while sauna bathing may affect the body’s ability to maintain blood pressure. In particular, the risk of an orthostatic hypotensive reaction is increased with concomitant faintings and accidents. Alcohol intoxication and particularly the hangover phase exposes a person to cardiac arrhythmias, and sauna may further increase the arrhythmia-risk due to enhanced adrenergic activity. Sauna bathing and heavy drinking, and also sauna bathing during hangover phase undoubtedly create real health risks.” 

Basically you’re more likely to faint, and have heart issues like cardiac arrhythmia when combining alcohol and sauna use (even if you’re just hungover).

Pregnant women may also want to think hard about sauna use. While it generally seems safe for pregnant women to use the sauna, those with toxemia (also known as preeclampsia, which causes high blood pressure usually during the second half of a pregnancy) should probably avoid it.

And for men who want to conceive children in the next six months it may also make sense to avoid sauna use, as one study found it may impair sperm production and function. However this impairment appeared temporary and fully reversed after six months of not using a sauna.

Some other potential sauna risks, especially regarding longevity, include the fact that longer bouts of heat exposure seem to be detrimental to lifespan extension.

In fruit flies, short amounts of heat exposure increase lifespan, but long bouts raise body temperature and metabolic rate and shorten lifespan. Higher body temperatures are also associated with shorter lifespans in most animals.

Plus, certain heat shock proteins like HSF1 may support some cancer cells’ resistance to certain types of cancer treatments.

This would seem to support the fact that studies have not found that heat therapy is beneficial for reducing the risk of cancer (though it does not appear to increase it, either.)

Systemic risks of sauna studies

Finally, there are some potential systemic risks to the type of studies being used to show positive health benefits from sauna use.

First, most of them are done in men, and most of those are also done in Finland, meaning some findings may not replicate to a more genetically diverse population, or to women.

Second, most of the recent research showing positive health benefits of sauna are done by the same research team. That is the team of Dr. Jari Laukkanen, who is so prominent in the sauna research field he was even interviewed by longevity influencer Rhonda Patrick.

This is not to say his research is flawed, but it is a little worrisome to see a large majority of studies cited on the health effects of sauna come out of a single team. If there are any errors in their methodology, or variables they didn’t track, those could be replicated across a variety of keystone studies.

For instance, a 2021 review looking at one of the Laukkanen studies advised caution, saying: 

“While these findings are very impressive, cautious interpretation of this study is warranted due to the lack of a true control group (the reference group still sauna bathed on average once per week), frequency and duration of sauna use only being determined at the time of enrollment, likely greater sauna use by individuals with higher income, education and discretionary time, and no inclusion of women.”

And third, most of the research on sauna use is only done over short periods of time, and few studies and controlled trials look beyond a six week time frame.

The same review quoted above bemoaned the lack of longer-term studies on heat therapy benefits, noting, “There is a decided lack of long-term intervention studies on the benefits of heat therapy, particularly in relation to the number of studies investigating the cardiovascular responses to an acute bout of passive heating.”

Does that mean all the previous studies are bunk and should be discarded? 

No.

But it does mean you should approach sauna bathing (as with any longevity intervention) cautiously, and ideally track and measure your biomarkers as you slowly introduce it into your longevity routine so you can make sure it’s helping, not hurting.

Some general guidelines for safe sauna use are:

1. NEVER combine sauna and alcohol (including if you are hungover).
2. Drink plenty of electrolytes before and after sauna use.
3. Don’t sauna bathe if you have unstable angina pectoris, recent myocardial infarction, or severe aortic stenosis.
4. NEVER sauna bathe alone.
5. Limit the length of time you sauna bathe to 20 minutes a session or less.
6. Don’t sauna bathe if you are a man trying to conceive within the next six months.
7. Don’t sauna bathe if you are a pregnant woman with toxemia.

But beyond safety, what is the optimal way to sauna bathe for health and longevity?

How to get the most benefits from sauna for longevity

To really get the most benefits from heat therapy for longevity you have to do a few specific things correctly.

Luckily, these aren’t that difficult.

Start slow and build up to higher temperatures and times

First off, don’t jump into a 248°F sauna and expect to be able to spend an hour or even 20 minutes in there.

For example, a 2024 study on women who only use the sauna infrequently suggested that it was better to start at a lower temperature of 80°C (176°F) rather than the higher temperature of 120°C (248°F), at least until your body has adapted and is able to bear the higher temperatures.

Otherwise, you risk heat exhaustion, nausea, and confusion.

Aim for temperatures of between 70–100°C (158°F– 212°F) and sessions of 5-20 minutes 

According to the most comprehensive scientific review I found, “Animal and some human studies have generally suggested that body core temperature should reach 38.0–38.5°C during sessions to reliably confer thermoregulatory adaptation.”

Given that, they found the following sauna practice and temperature reliably raised esophageal temperature to 39°C within about 10 minutes:

“In typical Finnish sauna sessions, individuals enter the sauna for 5–20 min at a time with 10- to 30-min rest periods outside the sauna in between. They may repeat this cycle one to five more times, depending on how accustomed they are to sauna use. During such sessions, the magnitude of core temperature increase depends on the air temperature and length of stay, which can range between 70–100°C and 15–30 min.”

Keep at it for at least 8-10 weeks

Most of the heat therapy research in animals suggests heat exposure needs to continue for more than four weeks in order for the animals’ cells to be fully protected from heat stress.

In humans, there is also now research suggesting that certain heat adaptations are not present after 4-5 weeks of heat therapy, but are present after 8-10 weeks.

So don’t give up on a heat therapy regimen after only a few weeks, even if you don’t seem to be seeing results yet.

How to get the longevity benefits of infrared sauna therapy

The studies showing positive health outcomes from Waon infrared sauna typically use session times of around 15 minutes, and temperatures of about 60°C (140°F), followed by 30 minutes wrapped in blankets to keep core body temperature high.

Because these saunas use far infrared waves that are able to penetrate the skin, lower air temperatures are needed to achieve similar results to a regular dry Finnish sauna.

Do I plan on adding sauna to my longevity routine?

Unfortunately, I don’t have a personal sauna at my house (Yet! Any sauna companies that would like to give me one for review are more than welcome), and I’ve struggled to find a nearby gym that has one as part of their membership.

So, while I am convinced of the benefits of sauna use for longevity, I may have to turn to more affordable options.

These include, as I mentioned above, infrared sauna products which seem to provide many of the same benefits as a traditional Finnish sauna. 

I’ll be researching these products over the next few weeks in order to write an article covering them for Longevity Advice.

Be sure to sign up below so you receive a notification as soon as that article is published!

But in general, once I do find a suitable sauna product, my routine will look something like this:

• 3-4 sauna sessions a week (studies seemed to show a dose dependent relationship between sauna use and health benefits, meaning the more frequently you do it the greater the benefits).
• 1-3 bouts of sauna use per session, of about 5-15 minutes each with 10 minute breaks in-between.
• Lots of electrolytes before and after, and never doing it when my wife is out of the house so there’s always someone around to check in on me if I faint.

Sauna health FAQs

Is sauna good for weight loss?

No. Studies have not found a significant amount of weight loss caused by using the sauna or other heat therapies. In fact, a 2013 study investigating hot bathing for weight loss found “no significant improvement” in body weight compared to the control group.

Can you sauna everyday? 

Yes, in fact many studies have found the health benefits of sauna use increase with the number of sauna sessions each week, in what scientists call a “dose dependent” manner. That means the more frequently you sauna bathe each week, the better your health results.

Is sauna safe during pregnancy?

Yes, sauna is safe for most pregnancies that don’t involve toxemia. Pregnant women with toxemia (also known as preeclampsia) should talk with their doctor before using a sauna.

Is sauna safe for kids?

Yes, provided they never use the sauna alone and keep sauna sessions short; in the 5-10 minute range. Children can’t regulate their body temperature through things like sweat as well as adults can, and may be more prone to fainting during longer sauna sessions. But, generally, sauna use is safe and may even be beneficial for kids.

Which is better for longevity, sauna vs. hot tub?

Hot tubs may actually be a better way to administer heat therapy than saunas. That’s because water transfers heat at a faster rate than air, and the body cannot cool itself as well under water because sweat needs evaporation in order to work. A 2019 study found that multiple hot tub sessions over an 8-10 week period improved markers for cardiovascular health among obese women with polycystic ovary syndrome.