There is a moment, a few minutes into a really good sauna, when the world softens. Your shoulders drop, your breathing slows, and a gentle warmth seems to reach right into your bones. For the Finns, who have around three million saunas for a population of five and a half million, this is simply part of life. For the rest of us, it might feel like an indulgence – a treat at the spa, a holiday luxury.

But what if that warmth were doing something far more profound? What if regular heat were one of the most underrated tools we have for protecting our hearts, our brains and our long-term healthspan?

Over the past decade, a remarkable body of research has emerged on deliberate heat exposure – from saunas to hot baths – and the findings are genuinely striking. As the evenings draw in and we instinctively crave warmth, there could hardly be a better moment to explore what the science says, where its limits lie, and how you can enjoy heat safely and wisely.

Why Would Heat Help Us Live Better for Longer?

To understand the excitement, we need to start with a concept I return to again and again in my work: hormesis. This is the principle that a small, manageable dose of stress can trigger a powerful repair-and-strengthen response in the body. Exercise works this way. So, in some respects, does fasting. And so does heat.

When your body temperature rises, your cells switch on a family of protective molecules called heat shock proteins. These act rather like a cellular maintenance crew – helping other proteins fold correctly, refolding those that have become damaged, and clearing away the ones beyond repair. Since the build-up of misfolded proteins is one of the recognised hallmarks of ageing, anything that keeps this maintenance crew in good working order is of real interest.

In a landmark study in tiny nematode worms, researchers found that the master switch for this heat response, a protein called HSF-1, was essential for the longevity effects of other well-known pathways – and that boosting HSF-1 activity actually extended lifespan.¹ Worms are not people, of course. But more recent human work is encouraging: when volunteers had heat applied to their thigh muscles for two hours a day over just six days, their muscle cells showed clear signs of building new, more capable mitochondria – the energy-producing “power stations” that tend to decline as we age.²

So there is a credible biological story here. Now let’s look at what happens in real human lives.

7 Remarkable Ways Regular Heat May Support Your Healthspan

1. A Stronger, More Resilient Heart

Much of what we know comes from an extraordinary long-term study in Kuopio, eastern Finland. Researchers followed 2,315 middle-aged men for a median of more than 20 years, recording how often they used the sauna. The results made headlines around the world: men who took a sauna four to seven times a week had a 50% lower risk of dying from cardiovascular disease, and a 40% lower risk of dying from any cause, compared with those who went just once a week.³ Their risk of sudden cardiac death was 63% lower.

Why might this be? During a sauna, your heart rate climbs and blood vessels open up to shed heat – a physiological workload that some researchers have likened to moderate exercise.⁴ Done regularly, this appears to train the cardiovascular system in a gentle but meaningful way.

2. Younger, More Flexible Blood Vessels

Stiff arteries are one of the key markers of an ageing cardiovascular system. In a carefully controlled trial at the University of Oregon, sedentary young adults sat in a 40.5°C hot-water bath for an hour, four to five times a week, for eight weeks. Compared with a sham group, they showed significant improvements in the function of the delicate inner lining of their blood vessels, reduced arterial stiffness and lower blood pressure.⁵ It was a small study, but it is important because it was a randomised trial – it shows cause and effect, not merely an association.

3. Healthier Blood Pressure – Especially When Combined with Exercise

In the Finnish cohort, men who used the sauna four to seven times a week had around a 46% lower risk of developing high blood pressure over the following years.⁶

And here is a finding I find particularly exciting. In a 2022 randomised trial, adults with at least one cardiovascular risk factor followed an eight-week exercise programme. Half of them added just 15 minutes of sauna after each session. The sauna group saw their systolic blood pressure fall by 8 mmHg more than the exercise-only group, and their cardiorespiratory fitness improved more too.⁷ This is the way I like to think about heat: not as a replacement for movement, but as a wonderful partner to it.

4. Reduced Risk of Stroke

Importantly, the stroke research from Kuopio included women as well as men. Among 1,628 adults followed for around 15 years, those taking four to seven saunas a week had a 61% lower risk of stroke than once-a-week users – and the benefit appeared similar for both sexes.⁸

5. A Healthier Brain

Perhaps the most intriguing finding of all: in the original cohort of Finnish men, those who used the sauna most frequently had a 66% lower risk of developing dementia, and a 65% lower risk of Alzheimer’s disease, over two decades of follow-up.⁹ Given how closely brain health is tied to the health of our blood vessels, this connection makes biological sense – although, as with all observational research, it cannot prove that sauna use itself was the cause.

6. A Lift for Mood

Heat has a fascinating relationship with mood. In a small but carefully designed trial, people with major depression received a single session of whole-body heating, raising their core temperature to around 38.5°C. Compared with a convincing sham treatment, their depression scores were significantly lower – and the effect was still measurable six weeks later.¹⁰ This is early-stage research and certainly not a substitute for professional care, but it hints at something many sauna lovers describe intuitively: that warmth can be deeply restorative for the mind.

7. Support for Your Lungs and Immune Resilience

Finally, as we head into the colder months, the Kuopio researchers also found that men who used the sauna four or more times a week had a lower risk of developing pneumonia – around 37% lower after taking other risk factors into account.¹¹ This finding was only just statistically significant, so I would treat it as promising rather than proven. Still, it adds to an intriguing overall picture.

No Sauna? Your Bath May Be the Next Best Thing

Not all of us have a sauna at the bottom of the garden – and the good news is that you may not need one. In Japan, where hot-tub bathing is a cherished daily ritual, researchers followed more than 30,000 adults for around 20 years. Those who bathed in hot water daily or almost daily had a 28% lower risk of cardiovascular disease and a 26% lower risk of stroke, compared with people who bathed twice a week or less.¹²

And remember, the Oregon blood-vessel trial used hot-water immersion, not a sauna.⁵ So a deep, warm bath at the end of the day may be offering you more than simple relaxation.

An Honest Word About the Evidence

You know I always want to give you the full picture rather than just the headlines, so here it is.

Most of the dramatic numbers above come from a single population in eastern Finland, and largely from middle-aged men. These are observational studies: they show that frequent sauna users had better outcomes, but they cannot fully rule out the possibility that people who use saunas often are also healthier, wealthier or more relaxed in other ways. The Japanese data, from a very different culture, points in the same direction – which is encouraging – and the smaller randomised trials on blood vessels and blood pressure show that heat does produce real, measurable physiological changes.

Taken together, I find the evidence genuinely compelling. But heat belongs alongside the true foundations of a long and vibrant life – regular resistance training, a colourful plant-rich diet, restorative sleep and meaningful connection – not instead of them.

How to Begin: Enjoying Heat Safely and Wisely

Heat is a stressor, and like any stressor it must be respected. A thorough review of the risks and benefits found that sauna bathing is well tolerated by most healthy adults, and that serious events are very rare – but it also identified important exceptions.¹³ Here is how I would suggest you approach it:

• Check with your doctor first if you have any heart condition, low or uncontrolled blood pressure, are pregnant, or take medication that affects blood pressure or heart rhythm. Unstable angina, a recent heart attack and severe aortic stenosis are clear reasons to avoid the sauna.¹³
• Never combine heat with alcohol. This is one of the most significant risk factors for sauna-related incidents, including dangerous drops in blood pressure and heart rhythm disturbances.¹³
• Start gently. Five to ten minutes is plenty at first. Most of the Finnish participants used saunas at around 80°C for roughly 15 to 20 minutes; there is no prize for enduring more than is comfortable.
• Hydrate well before and afterwards, and get up slowly – light-headedness is common as blood vessels dilate.
• Keep baths warm rather than scalding, particularly if you are older, and avoid very long soaks when you are tired or alone.
• Pair it with movement. If you have access to a gym or leisure centre with a sauna, try a short session after your strength workout – this is exactly the combination that produced extra benefits in the 2022 trial.⁷

Frequency seems to matter: in most of the studies, the greatest benefits were seen with four or more sessions a week, though two to three sessions were also associated with meaningful improvements. Begin where you can, and build up as it suits your body and your life.

The Warmth That Keeps on Giving

There is something deeply reassuring about this research. So many of the most powerful tools for a longer healthspan turn out to be ancient, simple and pleasurable – a walk in nature, a shared meal, a moment of awe, and now, it seems, the embrace of warmth.

So this autumn, as the temperatures fall, why not treat yourself to a sauna after your workout, or a long, warm bath before bed? Your heart, your blood vessels and perhaps even your brain may thank you for it. Think of it not as an indulgence, but as one more way to rewind your body clock.

Medical disclaimer: This article is for general information only and is not intended as medical advice. Please consult your doctor or a qualified healthcare professional before making changes to your health routine, particularly if you have a heart condition, high or low blood pressure, are pregnant, or take any regular medication.

References

1. Hsu AL, Murphy CT, Kenyon C. Regulation of aging and age-related disease by DAF-16 and heat-shock factor. Science. 2003;300(5622):1142–1145. https://doi.org/10.1126/science.1083701
2. Hafen PS, Preece CN, Sorensen JR, Hancock CR, Hyldahl RD. Repeated exposure to heat stress induces mitochondrial adaptation in human skeletal muscle. Journal of Applied Physiology. 2018;125(5):1447–1455. https://doi.org/10.1152/japplphysiol.00383.2018
3. Laukkanen T, Khan H, Zaccardi F, Laukkanen JA. Association between sauna bathing and fatal cardiovascular and all-cause mortality events. JAMA Internal Medicine. 2015;175(4):542–548. https://doi.org/10.1001/jamainternmed.2014.8187
4. Laukkanen JA, Laukkanen T, Kunutsor SK. Cardiovascular and other health benefits of sauna bathing: a review of the evidence. Mayo Clinic Proceedings. 2018;93(8):1111–1121. https://doi.org/10.1016/j.mayocp.2018.04.008
5. Brunt VE, Howard MJ, Francisco MA, Ely BR, Minson CT. Passive heat therapy improves endothelial function, arterial stiffness and blood pressure in sedentary humans. Journal of Physiology. 2016;594(18):5329–5342. https://doi.org/10.1113/JP272453
6. Zaccardi F, Laukkanen T, Willeit P, Kunutsor SK, Kauhanen J, Laukkanen JA. Sauna bathing and incident hypertension: a prospective cohort study. American Journal of Hypertension. 2017;30(11):1120–1125. https://doi.org/10.1093/ajh/hpx102
7. Lee E, Kolunsarka I, Kostensalo J, et al. The effects of regular sauna bathing in conjunction with exercise on cardiovascular function: a multi-arm, randomized controlled trial. American Journal of Physiology – Regulatory, Integrative and Comparative Physiology. 2022;323(3):R289–R299. https://doi.org/10.1152/ajpregu.00076.2022
8. Kunutsor SK, Khan H, Zaccardi F, Laukkanen T, Willeit P, Laukkanen JA. Sauna bathing reduces the risk of stroke in Finnish men and women: a prospective cohort study. Neurology. 2018;90(22):e1937–e1944. https://doi.org/10.1212/WNL.0000000000005606
9. Laukkanen T, Kunutsor S, Kauhanen J, Laukkanen JA. Sauna bathing is inversely associated with dementia and Alzheimer’s disease in middle-aged Finnish men. Age and Ageing. 2017;46(2):245–249. https://doi.org/10.1093/ageing/afw212
10. Janssen CW, Lowry CA, Mehl MR, et al. Whole-body hyperthermia for the treatment of major depressive disorder: a randomized clinical trial. JAMA Psychiatry. 2016;73(8):789–795. https://doi.org/10.1001/jamapsychiatry.2016.1031
11. Kunutsor SK, Laukkanen T, Laukkanen JA. Frequent sauna bathing may reduce the risk of pneumonia in middle-aged Caucasian men: the KIHD prospective cohort study. Respiratory Medicine. 2017;132:161–163. https://doi.org/10.1016/j.rmed.2017.10.018
12. Ukai T, Iso H, Yamagishi K, et al. Habitual tub bathing and risks of incident coronary heart disease and stroke. Heart. 2020;106(10):732–737. https://doi.org/10.1136/heartjnl-2019-315752
13. Hannuksela ML, Ellahham S. Benefits and risks of sauna bathing. American Journal of Medicine. 2001;110(2):118–126. https://doi.org/10.1016/S0002-9343(00)00671-9

Further Reading

• Muscle and Longevity
• Five Remarkable Health Benefits of Awe
• Urolithin A: 5 Breakthrough Discoveries
• Bone as an Endocrine Organ

About the Author

Jayney Goddard MSc, PG Dip Ed, FCMA, FRSM is the Founder and President of The Complementary Medical Association (The CMA), the world’s leading professional body for complementary medicine. With more than three decades at the forefront of complementary and integrative healthcare, Jayney has dedicated her career to raising professional standards across the sector and to championing rigorous, evidence-based natural approaches to health and longevity. She is the author of several best-sellers, including Rewind Your Body Clock – the Complete Natural Guide to a Happier, Healthier, Younger You (Watkins/Penguin Random House), which debuted on the Amazon charts at No. 1 among ALL books on the platform. Jayney is a sought-after international speaker and a passionate advocate for the safe, ethical integration of complementary medicine within mainstream healthcare. Through The CMA, she supports a global community of Practitioners, Fellows, and Approved Suppliers committed to the very highest standards of practice.