“Whatever it is, as long as it’s hot”
That’s Dan Gable, American wrestling icon.
There is a lot of truth to that because there is no perfect sauna temperature. Everyone’s heat tolerance is different.
He then goes on to say generally within the range of 170-220°F. This temperature range is consistent with the scientific research and within the sauna community.
The research on dry sauna temperature
A study shows using a dry sauna of at least 174°F reduces all-cause mortality. You’ll see dry sauna temperatures ranging from 160°F to 220°F. The majority of research is done on dry saunas, despite infrared saunas rise in popularity. This study tracked 2,315 middle-aged men and their sauna use over a median of 20 years and the average temperature was 174°F.
Frequency of sauna use and duration per session are also important factors to consider.
Dry Sauna Humidity
Dry saunas have a low humidity (around 10-20%). For context, a steam room, or Turkish bath, is about 100% humidity. Albeit at a much lower temperature (100-120°F). To increase the steam and humidity of a sauna, many sauna users pour water onto the sauna stones. In Finland, this is called löyly.
A common guideline is the “Rule of 200”. This means that the combination of air temperature and humidity should be around 200. If your sauna temperature is 180 and you pour water on the stones to increase the humidity by 20%, you are at an ideal sauna temperature. This is a general guideline and not a hard rule. As an experience sauna user, I go above the Rule of 200.
Infrared sauna temperature
Infrared saunas range usually from 110°F to 150°. Thermal radiation directly heats your body. The surrounding air is not as hot in an infrared sauna as it is in a dry sauna. Infrared saunas have almost no humidity.
There are ways to biohack your infrared sauna to make it hotter. I wrote an article about how Ben Greenfield does it here.
How often should you use the sauna?
The study above shows that the more frequently you use the sauna, the better the results. Frequent sauna users (4-7x / week) were 63% less likely to experience sudden cardiac death. They were also 37% less likely to die from all-causes of premature death. Moderate sauna users (2-3x / week) were 22% less likely to die from sudden cardiac death.
It’s not that complicated. Since the sauna has a similar effect on your body as exercise, it makes sense that the more frequently you “exercise” the better your results will be to an extent.
Ideally, you’d use the sauna between 4-7x per week. Realistic best practices are to use the sauna as frequently as you can based on your lifestyle.
How long to stay in a sauna?
Time in the sauna also affects cardiovascular related deaths. In that same study, those who used the sauna for 20 minutes or more were less likely to die from coronary heart or cardiovascular disease than those using the sauna for 11-18 minutes. It is best to work your way up to at least 20 minutes in the sauna.
How long should you stay in an infrared sauna?
You can stay in infrared saunas longer than dry saunas because the temperature is lower. With that said, there is no scientific research on exactly how long you should stay in an infrared sauna. Generally accepted times are from 25-60 minutes. Most spas offer infrared sauna sessions for 30, 45, and 60 minute session.
How to build heat tolerance
As mentioned, there is no perfect sauna temperature, duration, and frequency. You will become more heat adapted the more frequently you use a sauna. It is ok if you cannot last in a sauna for 20 minutes straight or cannot handle a certain temperature.
A great way to build your tolerance is as follows. Let’s say you can last in a dry sauna at 175 for 10 minutes. After being in the sauna for your maximum of 10 minutes, get out and cool off. Your cool off period can be a cold shower or just getting out of the heat. Then go back into the sauna for as long as you can. You will gradually build up tolerance.
The couch to 5k plan is a great example of this. You can go from your couch to running a 5k in 6 weeks using a crawl, walk, run approach. For example in week 1, you run 1 minute, walk 1 minute, and repeat. By the end of the 6 weeks, you are running 15 minutes and walking 1.
TL; DR: The research suggests using the dry sauna between 4-7x/ week, for at least 20 minutes at a time, and with a sauna temperature between 174-220. There is no research on best time, duration, and temperature for an infrared sauna.