After an injury, a health writer found healing in the heat. A Finnish MD/PhD world expert in sauna therapy explains the science behind the benefits.
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In my 20s, I could train hard, sleep it off, repeat—no particular strategy required. Now, as an athlete in her 30s who still wants to perform like she’s in her 20s, recovery protocols are non-negotiable. I’ve turned to anti-inflammatory nutrition, and am careful to stretch and work on my flexibility, while always looking for tools that offer real recovery, not just hype.
But none of that was on my mind when I stepped into a sauna on a vacation to Iceland. It was simply a spa day with my mom to escape the biting November cold. I also hoped the heat would ease the ache in my hip. I’d injured it months earlier in a fall during trapeze training, and while it felt mostly recovered, Iceland’s freezing temperatures triggered painful flare-ups.
Indeed, the dry, intense heat worked like a charm for my joints—but it also left me feeling unexpectedly calm, clear-headed, and energized. Back home, with a sauna sitting right outside my gym, I started to wonder if this could be more than a spa-like luxury.
Editor’s note: Speak with your doctor before trying a sauna.
About the expert
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Sauna use dates back nearly 10,000 years in Finland, where it remains such an integral part of daily life that it’s been recognized as a UNESCO Intangible Cultural Heritage of Humanity. Describing this environment as “a church of nature,” the Finns use saunas not only for warmth and relaxation, but for socializing, business, physical healing, and mental well-being.
Given how central sauna culture is to Finnish life, it’s no surprise that much of today’s research on sauna therapy comes from the region. To better understand the evidence-based health benefits of this ancient practice, I turned to a Finnish expert whose research focuses on traditional sauna use.
“During a sauna session, the body undergoes a controlled heat stress response,” Dr. Laukkanen explains. “Core body temperature rises modestly, typically by about [1.8–3.6°F], which triggers a series of adaptive changes.”
Among those: blood vessels open up, circulation improves, heart rate rises to a level comparable to moderate exercise, and sweating increases, which helps regulate your body temperature and fluid balance.
Heat exposure may also activate heat shock proteins (HSPs), which play a role in cellular repair and stress tolerance, though Dr. Laukkanen notes that this area needs further study. “Hormonal responses also occur, including temporary increases in norepinephrine, growth hormone, and endorphins,” he says.
Together, these reactions trigger “good stress” in the body, prompting the cardiovascular, circulatory, and nervous systems to adjust in ways that are thought to improve overall health.
“Importantly, benefits appear to be dose-dependent—regular exposure over months and years matters more than occasional use,” Dr. Laukkanen stresses. It’s the repeated, mild heat stress that promotes body-wide adaptations.
One of the most well-studied “adaptations” is heart health. “Large prospective cohort studies consistently show that regular sauna use is associated with lower risk of cardiovascular disease, hypertension, sudden cardiac death, and all-cause mortality,” he says. The idea is that over time, sauna use “trains” your system, improving blood vessel function, arterial flexibility, and blood pressure levels.
These benefits extend beyond heart health. Sauna heat also helps shift the body into a parasympathetic, rest-and-recovery state after a session. This nervous system adaptation may explain why regular sauna use is also strongly associated with reduced stress, improved mood, better sleep quality, and a lower risk of depressive symptoms, Dr. Laukkanen says.
According to a 2024 review of research co-authored by Dr. Laukkanen, regular sauna use is also associated with:
A reduced risk of chronic diseases, particularly heart disease and dementia.
Reduced symptoms of musculoskeletal disorders, such as arthritis.
Better respiratory health.
Lower inflammation.
Improvements in hormonal, immune, and metabolic function.
Perhaps most notably, long-term cohort studies (especially in Finnish populations) have consistently linked consistent sauna use with a longer, healthier lifespan.
Most research links sauna benefits to temperatures between 158 and 185°F, but extreme heat isn’t necessary. “A moderately hot sauna used regularly is far more beneficial than occasional extreme exposure,” Dr. Laukkanen explains.
For most people, two to four sessions per week is sufficient. As a newbie, he suggested I start on the lower end and aim for:
10 to 20 minutes per session.
One to three rounds with cooling breaks.
Hydration before and after (use electrolytes if needed).
“Listening to the body is critical; discomfort is not a sign of benefit,” he stresses, adding that treating the sauna like an endurance challenge is a common mistake. “Sauna bathing is best approached as a restorative health practice. Comfort, relaxation, and consistency are better indicators of effective use than pushing personal limits.”
Following Dr. Laukkanen’s guidance, I started with two weekly sauna sessions. I scheduled them after my workout and chose a time slot in the evening, hoping the sessions would support recovery.
I’ll admit, the first few sessions were pretty uncomfortable. Recalling Dr. Laukkanen’s direction, I listened to my body and tapped out early—but even these shorter exposures left me noticeably calmer and refreshed. While week one did feel like an absolute chore, the ritual soon felt easier, and I settled into rounds that felt challenging but restorative.
While most research on sauna use focuses on long-term health outcomes, I noticed some changes almost immediately: faster recovery, less muscle soreness, and more stable energy throughout the week. I was also particularly aware of my body shifting into its parasympathetic rest-and-recovery state. After sessions, my mental chatter seemed to quiet, I slept deeply, and woke up feeling unusually refreshed.
Still, the biggest surprise was my cardio fitness. Since injuring my hip, my aerobic capacity had taken a hit—I wasn’t walking or hiking as much as before. So when a friend suggested a hike with a steady incline, I fully expected to be huffing and puffing. Instead, I was shocked by how easily I could breathe through steep sections.
2023 research published in Mayo Clinic Proceedings—also co-authored by Dr. Laukkanen—helps explain why. It found that regular sauna bathing mimics some of the effects of aerobic exercise, suggesting it’s a useful tool for those who can’t meet physical activity guidelines due to injury or other limitations. In other words, even while sidelined, I may have been quietly training my cardio.
Sauna use is generally safe for healthy adults, but Dr. Laukkanen says to consult your doctor if you have heart disease, low blood pressure, conditions affecting heat tolerance, skin problems, or a current infection. “Avoid sauna use when dehydrated, intoxicated, or during acute illness, such as a fever,” he says. Take it slow when finishing up, too—standing up too quickly afterward can cause dizziness.
He also cautions against exaggerated claims, such as “detoxification” through sweating. “Most toxins are processed by the liver and kidneys, not sweat,” he explains. There’s also no meaningful evidence to suggest saunas promote fat loss or calorie burning comparable to exercise or that they trigger immune-boosting benefits beyond modest reductions in illness frequency.
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