How to Use a Sauna: 9 Tips for Better Sessions | NORDI

Most people use a sauna the same way: get in, get hot, get out when it stops being fun. That works. But a few small changes make sessions more comfortable, easier to repeat, and easier to build a real habit around.

Here is what actually matters, whether it is your first session or your five hundredth.

1. How long should you stay in a sauna?

Start with 10 to 15 minutes.

If you are new to heat, that is enough. Your body needs time to adapt to the cardiovascular load, and there is nothing gained by pushing to twenty minutes on day one and feeling wrecked afterward.

Once 15 minutes feels easy, most regular users move to multiple shorter rounds rather than one long one. A common pattern is three rounds of 10 to 15 minutes with a cool-down between each. Rounds are more sustainable than endurance. We like to stay in 20-25 minutes, 30 on rare occasions.

Get out if you feel dizzy, nauseous, or your heart is racing in a way that does not feel right. That is the signal, not the clock.

2. How hot should a sauna be?

A traditional Finnish sauna runs roughly 70–100°C (160–212°F) with low humidity, usually 10–20%.

Infrared saunas run cooler and heat you differently. Neither is wrong. They are different tools, and most of the long-term research has been done on traditional Finnish saunas, not infrared.

If you are building a heat habit for the first time, sitting on a lower bench in a traditional sauna is an easier entry point than lowering the temperature. Heat stratifies. The bottom bench can be 20 degrees cooler than the top.

3. How often should you use a sauna?

The most cited research here is a Finnish cohort study published in JAMA Internal Medicine in 2015, which followed 2,315 middle-aged men for a median of nearly 21 years. Participants who reported sauna bathing four to seven times per week had a lower risk of fatal cardiovascular events and all-cause mortality than those who went once per week.

Two important caveats. It is an observational study, which means it shows an association, not proof that the sauna caused the outcome. And a 2018 systematic review in Evidence-Based Complementary and Alternative Medicine looked at 40 sauna studies and found that most were small, only 13 were randomised controlled trials, and the overall evidence base is still thin.

The practical read: consistency looks more important than intensity. Three to four sessions a week is a reasonable target most people can actually hold. More is fine if you tolerate it well.

4. What should you drink before and after a sauna?

You lose fluid and electrolytes through sweat, and you do not replace them by sweating less.

Drink water before you go in, not just after. Add electrolytes if you are doing multiple rounds or sweating heavily, since plain water replaces volume but not sodium. Skip alcohol entirely. Alcohol combined with sauna heat is the single most consistently flagged risk factor in the sauna safety literature.

A rough marker: if you finish a session and your urine is dark for the rest of the evening, you under-drank.

5. What should you wear in a sauna?

This is the part most people get wrong without realising it.

Standard sauna wear is synthetic. Polyester gym shorts, nylon-blend swimsuits, elastane leggings. These are the same garments people wear to the gym, moved into a room at 180°F and worn against skin with open pores for twenty minutes at a stretch.

If you have the option, go with natural fibres. Undyed organic cotton and wool handle heat and moisture differently than synthetics, and there is no dye or finish sitting between the fabric and your skin. In Finland, the answer is simpler: people go in naked and sit on a towel.

Whatever you wear, bring a towel to sit on. It is standard practice and it keeps the bench clean.

6. Why wear a sauna hat?

Because your head sits in the hottest air in the room.

Heat rises. In a traditional sauna, the air around your head can be significantly hotter than the air at your chest. That is what usually ends a session — not your body reaching a limit, but your scalp and ears getting uncomfortable first.

A wool felt sauna hat works as insulation. Wool felt is a poor conductor of heat, so it slows the transfer of hot air to your scalp. The practical effect is that your head stays comfortable while the rest of you keeps warming, which is why sauna hats are ordinary equipment in Finland, Russia, and the Baltics and largely unknown everywhere else.

Two things a hat also does:

• Protects your hair from dry heat damage. Repeated exposure to hot, dry air is hard on hair. A hat is a physical barrier between your hair and that air.
• Protects your ears. Ears are thin, exposed, and usually the first thing to sting.

One thing to check before you buy: what the hat is made of. Many cheap sauna hats are synthetic felt or dyed wool. Synthetic felt in a 180°F room defeats the point. Dyed felt puts pigment against your scalp while you sweat.

The NORDÎ Sauna Hat is undyed Merino wool felt, made by hand at a hat workshop in Portugal. No dye, no synthetic lining, nothing between the wool and your head.

7. Should you do a cold plunge after the sauna?

Alternating hot and cold is called contrast therapy, and it is the traditional Finnish pattern: sauna, then cold water, then rest, then repeat.

The physiological logic is straightforward. Heat dilates peripheral blood vessels; cold constricts them. Cycling between the two produces a large swing in peripheral circulation. Whether that translates into meaningful recovery benefits is still debated in the research, and the effect sizes reported in recovery studies are generally modest.

What is not debated is that the cold makes the next round more comfortable. If you have access to a cold plunge, a lake, or just a cold shower, use it between rounds.

Go into cold water gradually if you are new to it, and never alone.

8. Sauna before or after a workout?

After, in most cases.

Sauna before training raises your core temperature and adds cardiovascular load before you have done anything, which usually makes the session harder rather than better. After training, the heat is a low-effort way to extend the warm state and it fits naturally into a cool-down.

The exception is heat acclimation. If you are specifically training for hot conditions, post-workout sauna is used deliberately for that adaptation.

Do not use a sauna to cut weight before an event. That is dehydration, not fat loss, and it comes back the moment you drink.

9. Sauna etiquette

Short version, mostly universal:

• Shower before you get in.
• Sit on a towel.
• Keep your voice down. Some saunas are social, some are silent — read the room.
• Do not pour water on the rocks in someone else's session without asking.
• Do not bring your phone in. Heat kills phones and it kills the atmosphere.
• Take your session outside the room if you need to talk at length.

Who should be careful with saunas?

Sauna use is generally well tolerated by healthy adults, but it is a cardiovascular load, not a passive activity.

Talk to a doctor first if you are pregnant, have unstable angina, recent heart attack, severe aortic stenosis, low blood pressure, or a history of fainting. Do not use a sauna while intoxicated. Do not use one alone if you have any reason to think you might pass out.

This article is general information, not medical advice.

Frequently Asked Questions

How long should a beginner stay in a sauna? Start at 10 to 15 minutes. Increase gradually once that feels comfortable, and move to multiple shorter rounds rather than one long session.

How often should you use a sauna? Three to four sessions per week is a realistic target for most people. The Finnish cohort research associated four to seven weekly sessions with the strongest outcomes, though that evidence is observational.

Does a sauna hat actually work? Yes, as insulation. Wool felt slows heat transfer to your scalp, so your head stays comfortable while the rest of your body warms. It also shields hair and ears from dry heat.

What should a sauna hat be made of? Wool felt. Merino wool felt is the standard. Avoid synthetic felt, which does not insulate the same way, and consider whether you want dyed felt sitting against a sweating scalp.

Can you wear a sauna hat in an infrared sauna? You can, though it matters less. Infrared saunas run cooler and heat you more directly than by heating the air, so the head-to-chest temperature difference is smaller.

What should you wear in a sauna? As little as the setting allows, and natural fibres when you do wear something. Undyed cotton and wool are better suited to heat and sweat than polyester or elastane. Always sit on a towel.

Should you drink water during a sauna? Drink before and after. Sipping during is fine. Add electrolytes if you are doing multiple rounds or sweating heavily.

Is it better to sauna before or after a workout? After, for most people. Before training it adds cardiovascular load without benefit, unless you are deliberately training heat acclimation.

Sources

1. 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.
2. Hussain J, Cohen M. Clinical Effects of Regular Dry Sauna Bathing: A Systematic Review. Evidence-Based Complementary and Alternative Medicine. 2018;2018:1857413.
3. American College of Sports Medicine; Sawka MN, Burke LM, Eichner ER, Maughan RJ, Montain SJ, Stachenfeld NS. ACSM Position Stand: Exercise and Fluid Replacement. Medicine & Science in Sports & Exercise.2007;39(2):377–390.
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.

NORDI makes an undyed Merino wool felt sauna hat, made by hand in Portugal. No dye, no synthetics, nothing between the wool and your skin.