The Sauna Ritual: Heat, Cooling and Rest

Heat and löyly: what a Finnish sauna feels like

A Finnish sauna is hot and comparatively dry. The Finnish Sauna Society recommends temperatures of 80 to 100 °C, and between throws of water the relative humidity is typically low, often in the range of 10 to 20 percent. That combination is what separates it from a steam room, which runs much cooler but close to saturated.

Löyly is the Finnish word for the steam that rises when water is ladled onto the hot stones of the stove. The air temperature barely changes, yet the burst of moisture makes the heat feel sharply stronger on the skin, because humid air transfers heat to the body more effectively. Small amounts, thrown a little at a time, give a soft and even löyly; a full bucket tends to give a harsh, brief sting.

Rounds: how long and how many

A round is one period in the hot room followed by one period of cooling. The Finnish Sauna Society notes that around 10 to 20 minutes at a time is usually appropriate, and Harvard Health advises staying in no longer than 15 to 20 minutes. There is no need to reach a target: leave when you feel sufficiently warm, and immediately if you feel faint or unwell.

Most people take two or three rounds, with breaks that can be as long as the time spent in the heat or considerably longer. Heat rises, so the upper bench is the hottest place; sitting lower, or lying down with feet level with the head, makes the heat more even and is gentler for beginners.

Cooling: shower, plunge, lake or snow

Cooling closes each round, and in Finland it can take many forms: a cool shower, a walk on the terrace in the open air, a swim in a lake or the sea, a roll in the snow, or a dip through a hole cut in the ice. Each works on the same principle of drawing heat away from the skin and resetting the body before the next round.

The intensity is a matter of preference rather than rule. Fresh air and a lukewarm shower are entirely valid; a cold plunge is a strong stimulus and is best approached gradually. People with heart or blood pressure conditions should ask their doctor before combining intense heat with sudden cold.

Rest and hydration

The rest phase is part of the ritual, not an interruption. Sitting or lying quietly for a while after cooling lets the pulse settle and the body return to its normal temperature, and it is often the moment people describe as the most calming.

A long sauna session involves considerable sweating. The Finnish Sauna Society suggests drinking before the sauna and taking water during the breaks, and Harvard Health recommends two to four glasses of cool water after a sauna. Water, juice or a non-alcoholic drink is the sensible choice; alcohol is better left until well after the last round, if at all.

Aufguss and etiquette

Aufguss, German for infusion, is a guided sauna session common in German-speaking countries and increasingly elsewhere. A sauna master pours water, often scented with essential oils, onto the stones and then moves the hot air around the room with rhythmic towel movements. A session usually lasts around a quarter of an hour, and it is acceptable to leave early if the heat becomes too much.

Etiquette in a shared sauna is mostly common sense. Shower before entering, sit on a towel so that sweat does not touch the wooden benches, and keep conversation quiet. The Finnish Sauna Society describes a peaceful atmosphere as its most important principle and asks bathers to check with others before adding water to the stove. Customs on clothing vary: in Finland, bathing naked in single-sex saunas is the norm, while mixed public saunas usually expect a swimsuit or towel, so it is worth checking the house rules.

What research suggests about regular sauna bathing

The most frequently cited study is by Tanjaniina Laukkanen, Jari Laukkanen and colleagues, published in JAMA Internal Medicine in 2015. It followed 2,315 middle-aged men from eastern Finland in the Kuopio Ischemic Heart Disease Risk Factor Study, recruited between 1984 and 1989 and followed until 2011. Men who reported four to seven sauna sessions per week had a markedly lower risk of sudden cardiac death, fatal coronary heart disease, fatal cardiovascular disease and death from all causes than men who reported one session per week.

A follow-up study in BMC Medicine in 2018, which included women, found a similar inverse association between frequent sauna bathing and fatal cardiovascular events. A 2018 review in Mayo Clinic Proceedings by Laukkanen, Laukkanen and Kunutsor summarised emerging evidence that sauna bathing may be linked to lower risk of high blood pressure, cardiovascular disease and other conditions, and discussed possible mechanisms such as reduced arterial stiffness and lower blood pressure.

These are observational findings. Sauna frequency was self-reported, and people who take a sauna several times a week may differ in health, income or lifestyle in ways that are hard to fully account for; a letter published in JAMA Internal Medicine in 2015 made exactly this point. The careful reading is that regular sauna bathing is associated with better cardiovascular outcomes in Finnish cohorts, not that it has been proven to prevent disease.

Who should be careful

For most healthy adults, a sauna at conventional temperatures is considered well tolerated. A review in The American Journal of Medicine by Hannuksela and Ellahham (2001) concluded that sauna bathing is safe for most people with stable coronary heart disease, but identified unstable angina, a recent heart attack and severe aortic stenosis as reasons not to take a sauna. Anyone with a heart condition, uncontrolled or low blood pressure, or who takes medication affecting circulation should consult a doctor first.

The same review found sauna bathing to be safe in uncomplicated pregnancies of healthy women, but pregnancy is a reason to keep sessions shorter and milder and to discuss sauna use with a midwife or doctor. Alcohol is the clearest risk: combined with heat it raises the likelihood of low blood pressure, irregular heart rhythm and accidents, and it should be avoided before and during a sauna. If you are ill or feel unwell in the heat, leave the room.

AUREFJORD designs architectural outdoor saunas for exactly this kind of unhurried ritual.

Frequently asked questions

Sources

1. Laukkanen T et al. Association Between Sauna Bathing and Fatal Cardiovascular and All-Cause Mortality Events. JAMA Internal Medicine, 2015
2. The Link Between Sauna Bathing and Mortality May Be Noncausal (letter). JAMA Internal Medicine, 2015
3. Laukkanen JA, Laukkanen T, Kunutsor SK. Cardiovascular and Other Health Benefits of Sauna Bathing: A Review of the Evidence. Mayo Clinic Proceedings, 2018
4. Laukkanen T et al. Sauna bathing is associated with reduced cardiovascular mortality and improves risk prediction in men and women. BMC Medicine, 2018
5. Hannuksela ML, Ellahham S. Benefits and risks of sauna bathing. The American Journal of Medicine, 2001
6. Harvard Health Publishing: Saunas and your health
7. Finnish Sauna Society: Sauna bathing and customs