How long should you stay in a sauna, and how many rounds should you do

How long one stay in the sauna should last

Finnish researchers Jari Laukkanen and Setor Kunutsor, writing in Progress in Cardiovascular Diseases in 2019, describe a typical sauna stay as lasting 5 to 20 minutes, depending on the temperature and the comfort of the bather, with some people staying longer. The same review gives the recommended air temperature as 80 to 100 C at the level of the bather's face, with relative humidity of 10 to 20 percent. InfoFinland, the Finnish public information service, puts the usual Finnish sauna a little lower, at 70 to 90 C.

Harvard Health Publishing is more specific about the upper end: stay in no more than 15 to 20 minutes. Japanese sauna guides tend to sit inside that window. The travel guide Rurubu gives 6 to 12 minutes for the hot room, and suggests beginners start with 6 to 8.

Treat the clock as a ceiling rather than a target. In a 2024 safety notice from Japan's Consumer Affairs Agency, Professor Shinya Hayasaka of Tokyo City University, a physician who specializes in the medical use of bathing, advises leaving the hot room once you have started to sweat instead of waiting until it drips, and leaving straight away if you feel your heart pounding. He adds that this applies during an Aufguss too, the event where staff fan hot air at the benches, even though it is awkward to walk out in the middle of one.

Where you sit changes the answer. The agency notes that in a room set to 100 C, one study measured the middle bench at 70 to 80 C and the lower bench near 50 C, and Professor Hayasaka says each step up adds roughly 10 C. Starting on a low bench and moving up once you are used to the heat gives you more control than trying to last a fixed number of minutes on the top row.

How many rounds, and what goes between them

A sauna visit is rarely one long sit. Laukkanen and Kunutsor describe the usual session as several short stays in the hot room, each followed by a cooling-off period, which can be a swim, a shower, or simply time at room temperature, and then something to drink. They also report that most Finns take a sauna two to three times a week on average.

Japanese sauna culture gives the cycle a fixed shape. One set is the sauna, a cold bath, and a rest in the open air, and Rurubu suggests two to three sets, with 1 to 2 minutes in the cold bath and 5 to 10 minutes of rest. The Samurai Sauna Magazine gives a slightly wider range of two to four sets, with 30 seconds to 2 minutes in water of 15 to 18 C.

Put those numbers together and three rounds of 10 minutes of heat, up to 2 minutes of cold and 10 minutes of rest come to a little over an hour. The Consumer Affairs Agency's advice also covers the end of the visit: once you finish, dry off quickly, get dressed, and sit in the rest area for about 30 minutes until your blood pressure settles before heading out.

Cooling down without the shock

The cold part is where the Consumer Affairs Agency is most direct. Going straight from the hot room into a cold bath exposes the body to a sudden temperature change that the agency compares to heat shock, and it notes that older people are more at risk. Its advice is to rinse off the sweat with lukewarm water first, then pour cold water over your hands and feet so the body adjusts before you get in.

Laukkanen and Kunutsor make the same point from the medical literature. Alternating heat and cold water puts a substantial strain on the cardiovascular system, they write, and a number of deaths have been reported in people who dived head first into cold water immediately after a sauna. They advise that people with unstable cardiovascular disease avoid heat and cold immersion altogether.

The cold bath is not compulsory. The agency says that anyone who dislikes it, or who feels unwell in it, does not need to use it, and can alternate the sauna with a rest in the open air instead.

Water, alcohol, and days to skip the sauna

You lose more water than it feels like. Professor Hayasaka cites a report that a 10 minute sauna produces about 500 mL of sweat, around 1 percent of body weight. The Japan Sauna and Spa Association gives a slightly lower figure of about 300 to 400 mL per sauna in its 2025 Totonou 2.0 guidance, and recommends 200 to 250 mL of water before the sauna and the same again after. The agency's advice is one to two glasses before and after, plus small drinks in between, and Harvard Health suggests two to four glasses of cool water after each sauna.

Alcohol is the one thing every source rules out. Harvard Health says to avoid alcohol, and medicines that impair sweating, before and after a sauna. Laukkanen and Kunutsor note that alcohol was estimated to be a key contributing factor in reported cases of sudden death and stroke linked to sauna use. Professor Hayasaka's list of times to stay out includes after drinking, including a hangover, right after a meal, right after exercise, and whenever you feel unwell or have a fever.

Some people should ask a doctor first. Harvard Health names uncontrolled high blood pressure and heart disease. The Consumer Affairs Agency's expert adds a history of stroke, heart disease, high blood pressure under treatment, and pregnancy.

This is general safety information, not medical advice. If you have a heart condition or high blood pressure, or if you are pregnant, talk to your doctor before using a sauna, and stop right away if you feel dizzy or unwell.

Common mistakes that spoil a session

Sitting out the clock. The most common error is deciding on a number of minutes and staying for it no matter how you feel. The time ranges above describe what people usually do, not a goal to beat.

Forgetting the room itself. Of the 82 people injured in the 78 sauna incidents the Consumer Affairs Agency found in its accident database up to April 2024, burns were the most common injury with 31 cases, followed by cuts and scrapes with 24 and fractures or bruises with 14. Metal jewelry, locker keys, light fittings and the glass in the door can all get hot enough to burn, and throwing a lot of water on the stones at once releases a burst of steam. The agency also warns about wet floors and doors, and about rushing out of the room because you feel too hot.

Ignoring the trend in the numbers. The agency's database logged about four sauna incidents a year from fiscal 2014 to 2021, then ten in each of fiscal 2022 and 2023, as sauna use grew. The agency's advice for avoiding them comes down to basics: shower first, start on a low bench, cool down gradually, and do not push through discomfort.

Not knowing what you actually did. People tend to settle on timings that feel right and then repeat them from memory. Writing down each round, even roughly, shows you how long you really stayed. SteamLog, for example, walks a timer through sauna, cold plunge and rest in order and sends a notification when each phase is up, and a round you like can be saved to My Sets. It records what you did; it does not tell you one set is better than another.

Frequently asked questions