How to Use a Sauna: Temperature, Timing and What It Actually Burns

How to use a sauna, short answer: heat for 10 to 15 minutes at 80–90 °C on the upper bench, cool down completely for at least as long as you heated, repeat two or three times, and drink water between rounds. Everything else — the temperature you argue about, the calories you hope to burn, the löyly ritual — is detail on top of that pattern.

Most sauna advice online is written by people who have never commissioned one. We build them, which means we spend our working life watching what actually happens on the benches: who overheats, who leaves too early, who ruins a good cabin by using it like a hot room. This is the practical version.

A sauna session is not one long sit. It is a cycle, and the cycle is what produces the effect people are after.

Round one, 8–12 minutes. Shower first and dry off — wet skin insulates and delays sweating. Sit on the upper bench if you want the real temperature, the lower bench if you are new, pregnant, older, or unsure. Leave when you feel properly hot, not when the clock says you should.

Cool down, 5–15 minutes. This is the half people skip and the half that does the work. Cold shower, plunge, or simply cool air — a cold plunge if you have one. Your heart rate needs to come down and your skin needs to stop sweating before you go back in.

Round two and three, 10–15 minutes. Most regulars do two or three rounds. Beyond that you are usually chasing something the sauna cannot give you.

Rest at the end, 10–20 minutes. Do not dress and rush out. The last cool-down is when blood pressure settles and the calm everyone talks about actually arrives.

Total: roughly 45 to 75 minutes. For how this changes with frequency, see our guide on how often to use a sauna, and for the timing question on its own, how long to stay in.

The number depends on which room you are sitting in, and the three types are not interchangeable.

The number on the wall is not the number you feel. Air in a sauna stratifies: the difference between the top bench and the floor is routinely 20–30 °C. A cabin reading 90 °C at the sensor may be 60 °C at your feet. This is normal and it is why the bench height matters more than the thermostat setting.

Löyly changes everything. Pouring water on the stones spikes humidity for a minute or two. The air temperature barely moves; the heat transfer to your skin rises sharply. That is why a 80 °C sauna with steam feels hotter than a dry 95 °C one. Use a ladle, not a bucket, and give the stones time to recover.

If the room cannot reach temperature, or takes more than 45 minutes to get there, the problem is almost always an undersized heater, an uninsulated glass wall, or unlined stone in a thermal suite. We cover the arithmetic in our commercial specification guide.

This is the question with the most nonsense attached to it, so here is the honest version.

Sitting in a sauna raises your metabolic rate — your heart rate climbs to something like light-to-moderate exercise, typically 100–150 beats per minute for a healthy adult. That is real, and it is measurable. But the energy cost is modest: roughly 1.5 to 2 times your resting metabolic rate, which for most adults works out to something in the range of 20 to 40 calories per ten-minute round, not the hundreds sometimes claimed.

The weight you lose on the scale afterwards is water, not fat. A heavy session can shed half a kilo to a kilo of sweat. You will drink it back within hours, and you should. Treating that number as fat loss is the single most common misreading of a sauna.

What the research does support is more interesting than calorie burn: regular sauna bathing is associated with lower blood pressure and improved cardiovascular markers (PMC5941775), and heat exposure triggers cellular responses — heat shock proteins, improved vascular function — that exercise also produces. We looked at the blood pressure evidence in detail in our guide to sauna and blood pressure.

Use the sauna because it is good for recovery, circulation and sleep. If your goal is fat loss, the sauna is a companion to training, not a substitute for it — the same conclusion we reached in our review of sauna and muscle recovery, where the evidence is more mixed than the marketing suggests.

You lose 0.5–1 litre of sweat in a normal session, more in a hot one. Drink water before you start, between rounds, and after. Electrolytes matter if you are doing three or more rounds or sweating heavily — plain water alone, in volume, dilutes what you have left.

Alcohol before or during a sauna is the one rule that is not negotiable. It impairs thermoregulation and blunts the warning signs your body uses to tell you to leave. Finnish sauna deaths, rare as they are, correlate with it.

They sit on a towel. Not for modesty — for the wood. Sweat is the fastest way to stain and degrade a bench.

They dry off before entering. Wet skin delays the point at which you start sweating properly.

They leave the door closed. Every opening dumps the upper-bench heat and takes minutes to recover.

They cool down properly. Not a quick rinse — a full cool-down until the skin stops sweating.

They stop when the body says stop. Dizziness, nausea, headache or a racing heart are not something to push through.

They let the cabin dry afterwards. Leave the door ajar and let the ventilation run. This single habit adds years to a cabin’s life. The rest of the etiquette-versus-safety distinction is in our guide to sauna rules.

Heat is a cardiovascular load. If you are pregnant, have unstable heart disease, uncontrolled blood pressure, or are recovering from a recent cardiac event, ask a doctor before you use one — not because saunas are dangerous, but because the load is real and personal circumstances vary. Children tolerate heat poorly and should have short sessions on the lower bench with an adult present.