Little-Known Facts About Saunas: Beyond Just “Sweating in Heat”
A sauna may seem like a simple experience of “sweating in high heat,” but it actually hides many little-known facts that challenge conventional wisdom. Covering historical details, health misconceptions, cultural differences, and dos and don’ts for use, even frequent sauna-goers may not be aware of them—making them especially useful for anyone looking to enjoy saunas more safely and knowledgeably.
1. Saunas Were Originally a “Necessity for Survival,” Not a “Wellness Activity”
The “Smoke Residue Layer” of Finnish Smoke Saunas: A Natural “Air Purifier” and “Humidity Regulator”
Finland’s oldest “smoke saunas” (Savusauna) focus not on “heating” but on “smoking”: by slowly burning pine and birch wood for hours, smoke condenses into a dark brown layer of smoke residue inside the sauna room. As previously mentioned, this layer is naturally antibacterial, but it also has hidden functions: it absorbs dust from the air, acting as a “natural air purifier”; at the same time, it releases moisture slowly, preventing the sauna from becoming too dry and making the high-temperature environment “warm and gentle rather than harsh.”
2. Can Saunas Deeply Cleanse the Skin? Excessive Cleansing Actually Damages the Skin Barrier
Many people believe that “saunas open pores to flush out dirt, leaving the skin cleaner.” However, the skin’s surface has a “sebum membrane”—composed of oils secreted by the sebaceous glands—that locks in moisture and defends against external irritants. If a sauna session is too long (over 20 minutes) or the temperature is too high (over 90°C), the intense heat will over-dissolve this sebum membrane, causing the skin to “lose oil and moisture.” Instead of feeling cleaner, the skin becomes dry, sensitive, and even flaky. This is especially true for people with dry skin: if they don’t apply moisturizer promptly after a sauna, their skin barrier will be damaged.
Proper practice: Limit each sauna session to 10–15 minutes, and apply a mild moisturizer within 30 minutes after your session to lock in skin moisture.
3. Avoid “Deep Breathing” in Saunas—”Shallow Breathing” Is More Comfortable
Many people instinctively take deep breaths when entering a high-temperature sauna, thinking it helps them get more air. However, in a high-temperature environment, the air is less dense and contains slightly less oxygen than at room temperature. Deep breathing can overexpand the lungs, easily leading to chest tightness or dizziness. Additionally, deep breathing speeds up heat loss from the body, making you feel “tired” more quickly.
Proper practice: Maintain slow, shallow breaths—around 10–12 breaths per minute. This allows your body to adapt to the high temperature gradually, helping you stay in the sauna longer without feeling suffocated.
4. Don’t Use Saunas Naked (in Public)—Cotton Shorts Are Healthier
Many people think “naked saunas are more breathable,” but in public saunas (even gender-separated ones), sitting naked exposes your skin directly to wooden benches. This makes it easy to come into contact with bacteria (such as fungi) left by others, increasing the risk of skin infections. Moreover, sweat and sebum from your body can stick to the wooden surfaces, making them hard to clean and affecting subsequent users.
Proper practice: Wear loose cotton shorts (they absorb sweat, are breathable, and won’t suffocate the skin). Women can pair them with cotton camisoles. This ensures hygiene while still allowing the skin to sweat normally.
5. There’s a Trick to Pouring Water on Heated Stones: “Small, Frequent Amounts” Are Better Than “A Lot at Once”
Many people like to pour water on the sauna’s heated stones to create “instant steam,” thinking “thicker steam is more comfortable.” However, pouring a large amount of water at once (e.g., more than half a cup) will cause the stones to cool down rapidly, lowering the overall temperature of the sauna and requiring more time to reheat. Additionally, a large burst of water will make humidity spike to over 90%, easily making you feel suffocated.Proper practice: Pour 1–2 tablespoons (about 15–20ml) of water each time, with 3–5 minute intervals between pours. This releases steam slowly, keeping humidity at 50–60% (for dry saunas) or 70–80% (for steam saunas)—the most comfortable range for the human body.
These little-known facts not only help you avoid common pitfalls when using saunas but also let you understand the reasoning behind different types of saunas. Next time you use a sauna, try paying attention to these details—you’ll stay safer and enjoy a more satisfying sauna experience.