What does the research say?
Many claims are made about the health benefits of saunas. Here we summarise what research has shown and how reliable the evidence is. Most studies of traditional saunas come from Finland and show associations, not cause and effect. People who use saunas often may also live healthier lives in other ways.
A Finnish study followed 2,315 middle-aged men for about 20 years. Those who used a sauna 2–3 times a week had a 23% lower risk of dying from cardiovascular disease than those who went once a week. For those who went 4–7 times a week, the risk was 48% lower. (Laukkanen et al., JAMA Internal Medicine, 2015)
Blood pressure drops temporarily after a sauna session. In a long-term study, those who used a sauna most often had about a 47% lower risk of developing high blood pressure. Randomised trials are needed to confirm the effect.
In a study of 1,628 men and women, those who went 4–7 times a week had about a 62% lower risk of stroke than those who went once a week.
In the same group of Finnish men, those who went 4–7 times a week had a 66% lower risk of dementia and a 65% lower risk of Alzheimer’s disease.
In a small randomised study (37 people for 8 weeks), sauna therapy significantly reduced tension headaches.
Older studies suggest that sauna may ease symptoms of osteoarthritis, rheumatoid arthritis and fibromyalgia, but the evidence is weak.
An infrared sauna heats the body more directly, so people sweat at a lower air temperature. It has been studied much less than the traditional sauna.
A review of nine studies found limited evidence that infrared saunas may lower blood pressure and help people with heart failure. (Beever, Canadian Family Physician, 2009)
One study suggests a benefit for chronic pain.
In a small randomised trial (29 people with depression), a single treatment in which the body was heated significantly reduced depressive symptoms for up to 6 weeks, compared with a sham treatment. A specialised medical device was used, not an ordinary infrared sauna, and the results need to be confirmed in larger studies. (Janssen et al., JAMA Psychiatry, 2016)
Studies suggest that infrared saunas do not lower cholesterol. There is also no reliable evidence that sweating “flushes toxins” out of the body.
All the studies on infrared saunas were small and short.
In a steam room the temperature is lower than in a sauna, but the humidity is close to 100%. Sweat does not evaporate, so the heat feels stronger than the thermometer says. Steam rooms have been studied much less than dry saunas.
The body reacts to the heat of a steam room in a similar way as in a sauna, with a faster heart rate and widening of the blood vessels. However, no long-term studies show the same links to heart health that have been found for Finnish saunas.
Many people find that warm, humid air eases a blocked nose. However, a Cochrane review of studies on heated, humidified air found no clear benefit for the common cold, and the data were limited and unreliable. (Singh et al., Cochrane, 2017)
Many people find steam rooms relaxing, but this has been little studied specifically.
Keep sessions short, 10–15 minutes, and drink water. Humidity and heat together can make some people dizzy.
A gusa is a guided ritual in a dry sauna, so the same evidence as for dry saunas applies to the heat. There are no studies specifically on gusa sessions.
This information is general and does not replace advice from a doctor.