1.9 - Sauna

If you've followed the case for cold therapy in the previous chapter, sauna is the natural other half. Heat and cold are complementary practices, and both work through the same underlying principle: deliberately stress the body in a controlled way, and the body adapts in ways that improve almost everything about how it functions over time.

Sauna isn't a particularly radical recommendation these days. It's very much gone mainstream. Athletes use it. Longevity researchers and podcasters routinely cite it. Home saunas, once rare, are now common among people who take their health seriously. If you've considered adding one to your life, you probably already know several people in your circle who have.

When we first moved to Estonia, I was struck by how deep the sauna culture goes here. Roughly one-third of all apartments have a sauna built in. I had seen saunas in private houses before, but in apartments? Almost unheard of anywhere else I'd lived. Beyond the apartments, almost every gym, locker room, pool, or paddle tennis club has a sauna attached. It's an assumption here, not a luxury. The Estonians and Finns aren't using sauna because of a podcast. They're using it because their grandparents did, and the long-term results have been speaking for themselves for centuries.

The case for sauna is, if anything, even stronger than the case for cold. Cold therapy is supported by mounting research and a lot of enthusiastic anecdotes. Sauna is supported by a striking longitudinal study in modern wellness research, plus thousands of years of practice in Finnish, Russian, Turkish, and Central Asian cultures that built entire bathing traditions around it.

What sauna actually does

When you sit in a hot room, your body has to work hard to keep its core temperature stable. The heart rate climbs to the equivalent of moderate exercise. Blood vessels dilate to move warm blood to the skin, where sweat evaporates and cools you down. Cardiovascular output increases. Sweating clears out everything from heavy metals to metabolic waste.

At the cellular level, heat triggers the production of heat shock proteins, molecular machinery that helps repair damaged proteins and protect cells from future stress. These proteins are part of why sauna shows up so consistently in longevity research.

The mood and stress component matters too. Sauna releases endorphins similar to a runner's high. Cortisol drops. Many people report a clarity and calm after a sauna session that lasts hours.

And it just feels good. Sauna is one of the rare practices that's genuinely pleasant while still doing serious physiological work.

The Finnish research

The most compelling evidence for sauna comes from a long-running study at the University of Eastern Finland called the Kuopio Ischemic Heart Disease Risk Factor Study. Researchers followed about 2,300 middle-aged Finnish men for over twenty years, tracking their sauna habits and their health outcomes.

The findings:

• Men who used the sauna 4-7 times per week had a 40% lower all-cause mortality compared to men who used it once a week.

• Cardiovascular death dropped by about 50%.

• Risk of sudden cardiac death dropped by about 60%.

• Risk of Alzheimer's and dementia dropped by 65%.

These numbers are observational, not causal proof. The Finnish men who saunaed frequently might differ in other ways. But the magnitude of the effect is hard to dismiss, and follow-up studies in other populations have shown similar patterns. As a piece of longitudinal data, this is one of the cleanest signals we have on any wellness practice.

A few takeaways:

• More is better, within reason. The benefit scales with frequency.

• The effect is strongest at 4+ sessions per week.

• Session length matters too. Sessions of 20+ minutes show stronger effects than shorter ones.

Types of sauna

Several different practices fall under the "sauna" umbrella, and they're not interchangeable.

Traditional Finnish sauna. Dry heat at 80-90°C (175-195°F), with the option to throw water on hot stones to produce löyly (steam). This is what most of the research is based on. Standard Finnish practice is 15-30 minute sessions, sometimes followed by a cold plunge or shower.

Russian banya. Similar temperatures to Finnish sauna but with more humidity. The banya tradition often includes platza, the practice of being gently beaten with bundles of birch or oak leaves (venik) while hot. It sounds strange, but it's an incredibly invigorating experience.

Steam room. 100% humidity at around 43-49°C (110-120°F). Different protocol from a true sauna. Less research support, but still a useful practice for circulation and respiratory comfort.

Infrared sauna. Lower air temperature 50-60°C (120-140°F) with infrared light that heats your body directly rather than the air around you. Easier on people who can't tolerate the high heat of a Finnish sauna. The research base is much thinner, but the practice has become popular and many people find it more accessible.

Traditional Finnish or banya delivers the deepest benefit if you can access one. Infrared is a reasonable substitute if heat tolerance is an issue or if a Finnish sauna isn't available.

How to use it

A simple protocol that works:

• Frequency: Aim for 3-4 sessions per week to start. More if you can. Daily is fine for people who like it.

• Duration: 15-25 minutes per round at 80-90°C (175-195°F). Multiple rounds with cool-down breaks (sit in cooler air, drink water, return) are common.

• Hydration: Drink water before, during if needed, and after. Add a pinch of salt or an electrolyte mix if you sweat heavily.

• What to wear: Most traditional saunas are done without clothing (it's hygienic with a towel between you and the bench, and clothing traps moisture). If you're at a gym or mixed-gender public space, swimwear is the norm.

Listen to your body. If you feel dizzy, lightheaded, or nauseous, leave the sauna and cool down. Heat is a real stressor; don't push through warning signs.

Contrast therapy: sauna plus cold

Stacking sauna with cold exposure, a Finnish tradition for centuries, amplifies the benefits of both.

The protocol: do a round in the sauna (15-20 minutes), then immerse in cold water (a lake, a cold plunge, a cold shower) for 1-3 minutes, then return to the sauna. Repeat 2-4 cycles, finishing with cold.

The contrast does something neither one alone does. The blood vessel dilation from heat followed by the rapid constriction from cold creates a pumping action through the circulatory system. The nervous system gets a thorough reset. Many people describe the post-contrast state as one of the cleanest, most alert feelings they ever experience.

If you have access to both, do them together. Some people do sauna alone, then a cold shower at the end. Even that simpler version is highly effective.

Practical access

The biggest practical question with sauna is finding one that's available enough to use regularly.

• Public saunas, banyas, and bathhouses. In cities with Finnish, Russian, Korean, Turkish, or Japanese populations, you can often find traditional bathhouses for $20-40 a session. These are usually the highest-quality saunas available. Worth the effort to find a good one near you.

• Gym memberships. Many gyms have a sauna. The quality varies widely. Some are good Finnish-style; others are barely warm. Visit and check the temperature before committing.

• Home sauna. A traditional sauna built into a home is a real investment ($3,000-15,000 for a quality build). A barrel sauna for a backyard is at the lower end and is more affordable than an indoor build. An infrared sauna for indoor use can be had for $1,500-3,000.

• Compact options. Single-person sauna tents and infrared blankets exist for under $500. The experience is significantly weaker than a real sauna, but some of the benefits of infrared exposure remain.

The right path depends on your situation. If you have a good banya or public sauna nearby, that's often better than spending on a home setup. If you can build the practice into your home, the convenience makes daily use realistic in a way a 20-minute drive doesn't.

Safety and cautions

Sauna is generally safe for healthy adults, but a few cautions are real:

• Heart conditions. If you have heart disease, recent heart attack, severe arrhythmia, or unstable blood pressure, talk to your doctor before starting sauna. The cardiac load during a session is similar to moderate exercise. It can be safe with the right green light from a cardiologist, but it's not something to start blind.

• Pregnancy. Saunas can elevate core body temperature in ways that may not be safe for a developing fetus, especially in the first trimester. Most guidance is to avoid sauna during pregnancy unless your doctor specifically approves it.

• Alcohol. Don't drink and sauna. Alcohol increases dehydration, vasodilation, and arrhythmia risk; combining the two causes more deaths than the sauna itself. Finnish and Russian data confirm this clearly. Coffee before is fine (even though not recommended) if you're well-hydrated; alcohol is not.

• Dehydration. Drink water before and after. If you sweat heavily or sauna often, add electrolytes.

• Children. Children can use sauna but for shorter durations at lower temperatures. Most traditions ease kids in gradually.

• Medications. Some medications (especially those affecting blood pressure, fluid balance, or heart rhythm) can change how your body handles sauna. Check with your prescriber.

When in doubt, start short (10-15 minutes), at moderate temperature, and build up.

The principle

Heat therapy is hard to beat for cardiovascular health and longevity, and it's pleasant to do, which means it's one of the few wellness practices that sustains itself once you start.

If you can do sauna 3-4 times a week, you're doing something with as much long-term impact as exercise itself. Combined with cold, it becomes among the most efficient health stacks available. Find a sauna near you. Make it a regular practice. Pair it with the cold work in the previous chapter. The body will respond.