Sauna and steam
Dry heat, wet heat, infrared. Not the same thing.
A Finnish sauna, an infrared cabin and a steam room all make you hot, but they do it differently, at different temperatures and humidity. The best-known sauna findings come from traditional Finnish saunas, and they are often borrowed to sell the other kinds. Each type has its own body of evidence, and the amounts are very different.
Side by side
The types at a glance.
Air temperature and humidity are given as the studies ran them. The last two columns come from the graded records: how much trial evidence each record's PubMed search found, and the letter the record holds.
| Type | Air temperature | Humidity | How the heat reaches you | Trial literature on the record | EBL record |
|---|---|---|---|---|---|
| Traditional Finnish saunadry sauna | About 80 degrees Celsius (176 degrees Fahrenheit) or higher; 79 to 81 in the trials that reported it | Low, 13 to 23 percent, with brief bursts when water hits the stones | Hot air, heated by a stove | 4 eligible of 27 screened in PubMed (2026-10) | C Traditional Finnish Sauna (dry sauna) |
| Infrared saunafar-infrared cabin | Lower than a Finnish sauna; 60 degrees Celsius in the trials | Low | Infrared panels warm the skin directly; the air stays cooler | 8 eligible of 117 screened in PubMed (2026-10) | C Infrared Sauna |
| Waon therapythe Japanese protocol | 60 degrees Celsius for 15 minutes, then 30 minutes resting under a blanket | Low | A far-infrared dry sauna used on a fixed schedule | 8 eligible of 117 screened in PubMed (2026-10) | C Infrared Sauna |
| Sauna blankets, domes and podsportable infrared | Varies by product | Low | Infrared elements in a bag or shell around the body | 8 eligible of 117 screened in PubMed (2026-10)Graded with infrared saunas; no trial has tested these products themselves. | C Infrared Sauna |
| Steam roomsteam bath, Turkish hammam | Lower than a sauna; 44 degrees Celsius in a 2023 pod study | Near 100 percent | Water vapor; sweat cannot evaporate, so the body heats at a lower air temperature | 0 randomized trials of this exposure against none; 11 records screened (2026-10) | D Steam Room (steam bath, hammam) |
| Russian banya | Hot, with water thrown on a stove | Higher than a Finnish sauna, varies by bath | Hot humid air, often with a birch or oak whisk | No randomized trial found. Closest records: Finnish sauna and steam room. | No record |
| Steam inhalationbowl of hot water or steamer | Breathed in, not sat in | Saturated vapor | Hot vapor to the nose and airways only | 2 eligible of 28 screened in PubMed (2026-10) | D Steam Inhalation (for colds and sinus symptoms) |
Dry heat
The traditional Finnish sauna, and the famous numbers.
A Finnish sauna is a wooden room heated by a stove. The air is very hot and dry: in the trials that reported it, about 79 to 81 degrees Celsius (174 to 178 degrees Fahrenheit) at 13 to 23 percent humidity (PMID PubMed ID: the permanent number the US National Library of Medicine gives a published paper. Each one links to that paper's record on PubMed. 37650138; PMID 32615263). Throwing water on the hot stones sends a brief wave of steam through the room, which feels much hotter than the thermometer reading.
The famous numbers. Almost everything said about sauna and long life comes from one study of men in Kuopio, eastern Finland, where most homes have a sauna. Among 2,315 men followed for about 20 years, those who used a sauna 4 to 7 times a week had fewer sudden cardiac deaths and fewer deaths from any cause than those who used it once a week (PMID 25705824). The same group reported less dementia (PMID 27932366) and, in a later sample of men and women, fewer strokes (PMID 29720543). These are observational Research that watches what people already do rather than assigning a treatment. It can show that two things travel together, not that one causes the other. findings. Men who use a sauna almost every day may differ from men who use it once a week in health, work and habits, in ways no statistical adjustment fully removes. They show a link, not that sauna caused the difference.
The trials. The randomized trials are small and run for weeks, not years. Adding 15 minutes of sauna after exercise lowered blood pressure and raised fitness more than exercise alone in 47 adults over 8 weeks (PMID 35785965). Sauna on its own, four times a week for 8 weeks, did not change blood vessel function or blood pressure in 41 people with heart disease (PMID 37650138). Headache pain eased a little in one 37-person trial (PMID 25636135). Breathing hot sauna air during a cold did not ease its symptoms overall (PMID 21143077).
Radiant heat
Infrared saunas and Waon therapy.
An infrared sauna warms the body with infrared panels rather than by heating the air, so the cabin runs much cooler than a Finnish sauna and the heat reaches the skin directly. In a crossover A trial design in which each participant receives both the treatment and the comparison, one after the other, and serves as their own control. study of 10 healthy women, 45 minutes in an infrared sauna raised body temperature more than moderate cycling did, and neither the sauna nor the cycling changed blood pressure, arterial stiffness or heart rate variability compared with rest (PMID 34954348).
Waon therapy is a Japanese protocol built on a far-infrared sauna: 15 minutes at 60 degrees Celsius (140 degrees Fahrenheit), then 30 minutes resting under a blanket, usually daily. Most of the randomized infrared evidence is Waon research in heart failure. The largest trial, 149 hospitalized patients, missed its main blood test endpoint The outcome a trial measures to decide whether the treatment worked, such as heart attacks, blood pressure or a symptom score., though walking distance and symptoms improved (PMID 27001189).
Near, far and full spectrum. Infrared cabins are sold by the wavelength they emit. The Waon trials used far-infrared. No trial found compares one wavelength with another on a health outcome.
Blankets, domes and pods. Portable infrared products wrap the body in a heated shell or bag. They are listed under the infrared sauna record, but no trial has tested them on a health outcome. The one study found measured only how reliably a portable infrared unit produced a set amount of dehydration in healthy young adults (PMID 41320841).
Wet heat
Steam rooms, hammams and the banya.
A steam room fills the air with water vapor until the humidity is close to 100 percent. The air is much cooler than in a sauna: a portable steam pod tested in 2023 ran at 44 degrees Celsius and 99 percent humidity, and an hour inside raised body temperature to about 38.1 degrees Celsius (PMID 37979477). Because sweat cannot evaporate in saturated air, the body loses its main way of cooling, so wet heat feels hotter than dry heat at the same temperature. In a study comparing kinds of heat, humid heat was tolerated less well than a hot bath, and tolerance did not improve over 5 days (PMID 35193165).
Hammam. The Turkish bath is a steam room tradition, usually combined with scrubbing and massage.
Banya. The Russian bath sits between the two: hot, humid air from water thrown on a stove, often with a whisk of birch or oak leaves. No randomized trial of the banya was found.
The evidence. No randomized trial has compared using a steam room with not using one on any health outcome. The trials that exist compared steam with herbs against plain steam in hay fever, where both groups improved equally (PMID 29397091), or combined a hammam with massage, so the steam cannot be judged on its own (PMID 39459464).
A different thing
Breathing steam is not sitting in it.
Steam inhalation means breathing the vapor from a bowl of hot water or a steamer, usually for a cold or blocked sinuses. It has been tested more than the steam room has. A Cochrane review of six trials in the common cold could not show that it helps (PMID 28849871). In 871 adults with long-lasting sinus symptoms, steam did not reduce how much the symptoms interfered with daily life, though headaches were a little better (PMID 27431306).
The harm is documented. Burn centers in the Netherlands and the United Kingdom treat scalds from tipped bowls of hot water every year, mostly in children (PMID 22781995; PMID 26917659).
Often cited, but not a sauna
Whole-body hyperthermia for depression.
A trial often quoted as proof that sauna treats depression did not use a sauna. Participants lay inside a heated chamber with the head outside, warmed by infrared lamps over the chest and heating coils at the legs, until core temperature reached 38.5 degrees Celsius; the sham A fake version of a procedure or device used as the comparison, so participants cannot tell which one they received. used the same chamber with non-heating lights and slight leg warmth. In 34 adults with major depression, one session lowered clinician-rated depression scores more than a sham session for 6 weeks (PMID 27172277). That is a different exposure from a sauna, run once under medical supervision, and EBL does not grade it here.
Cautions
What the studies of harm found.
Alcohol. Deaths in saunas are rare. In Finland they ran at fewer than 2 per 100,000 people a year, and half of those who died had been drinking (PMID 18471223). In a Swedish series, 71 percent of those tested had alcohol in the blood and nearly all were found alone (PMID 19749613).
Sperm. In 10 men using a Finnish sauna twice a week for 3 months, sperm count and motility fell sharply and recovered within 6 months of stopping (PMID 23411620).
Pregnancy. In 23,491 pregnant women, hot tub use in early pregnancy was linked with neural tube defects; the estimate for sauna pointed the same way but was not statistically significant Unlikely to be explained by chance alone at the threshold the study set. It says nothing about whether the difference is large enough to matter. (PMID 1640616).
Medicines. A sauna roughly doubled the rate at which injected insulin was absorbed and lowered blood glucose in people with type 1 diabetes (PMID 7000239), and raised the amount of nicotine absorbed from a patch (PMID 8841153).
Hot then cold. A heart attack has been reported after alternating between a sauna and rapid cooling in cold water (PMID 10085493).
Questions
What readers ask.
Is an infrared sauna better than a traditional one?
No randomized trial found has compared the two head to head on a health outcome. They are graded on separate records because the exposures differ and the trials were done on each separately.
Why do the Finnish numbers not set the grade?
EBL grades on randomized trials. The Finnish findings come from following people who chose how often to use a sauna, so they show an association. They are shown on the record, with what they found, so readers who meet them elsewhere can see where they sit.
Does a sauna blanket count as an infrared sauna?
It is listed with infrared saunas because it uses the same kind of heat. The trials behind that record used far-infrared cabins on the Waon protocol, and no trial has tested a blanket on a health outcome.
Is a steam room the same as breathing steam over a bowl?
No. One heats the whole body in humid air; the other sends hot vapor into the nose and airways. Steam inhalation has been tested in randomized trials and did not help; the steam room has not been tested against no steam.
Go further
From the types to the records.
The sauna evidence people quote is mostly Finnish and observational. Each type has to be judged on its own trials.
Educational use only, not medical advice.