Traditional Dry Saunas
In a traditional dry sauna, stones are heated by a wood fire, a stove, or an electric heater. To produce it’s heating effect, it uses convection (air currents) and conduction (direct contact of hot air with your skin to produce its heating effect). The heated walls and rocks emit a far-infrared heat. Combining this with the heated air creates an enveloping heat. It usually takes 30-45 minutes to heat up a traditional sauna depending on the size of the room and temperature.
Wood burning sauna
Most sauna enthusiasts prefer a wood fired sauna because it is the most traditional form of a sauna. It offers as similar experience to sitting by a wood fire as you watch the fire through the heat-resistant windows. The aroma of wood fills the sauna for added ambiance. Most people prefer oak, birch, or apple wood. There is no electricity needed.
An electric heater is common in America. It heats the room with an electric heater that heats stones, and that heat radiates throughout the room. This heats the air, which then warms your body. Electric heated saunas generally use more electricity than infrared due to the size and temperature.
You pour water over the stones to increase the humidity & heat. This creates steam called löyly in Finland. Sauna traditionalist say that a sauna is not a sauna if there is no steam. A ladle pours the appropriate amount of water. This also moistens your nasal passage and allows for the use of aroma therapy with essential oils.
How hot is a dry sauna?
You’ll see dry sauna temperatures ranging from 160°F to 220°F. The research shows using a dry sauna of at least 174°F reduces all-cause mortality. The majority of research is done on dry saunas, despite infrared saunas rise in popularity.
The maximum temperature an electric sauna heater can get in the USA is 194, according to the Underwriters Laboratory (UL 875). Frequency of sauna use and duration per session are also important factors to consider, discussed later.
The hottest point of a sauna is directly above the heater. Hot air rises so the coolest place in a sauna is the floor.
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.
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). As stated above, to increase the steam and humidity of a sauna, pour water onto the sauna stones.
How long do you stay in a dry sauna?
The research points to at least 20 minutes in the sauna. It is recommended to start slow and work your way up if you are a beginner. You become more heat adapted the more frequently you use the sauna. Therefore, you will be able to withstand the sauna at higher temperatures and longer duration. I discuss becoming heat adapted further down the page.
What is an infrared sauna?
An infrared sauna uses light to create heat. Infrared is a type of light wave on the electromagnetic spectrum that comes from the sun. When you stand in the sun, you feel heat and warmth. That is mainly from infrared. While there aren’t studies on infrared saunas, there are over 3,000 studies on infrared in general.
Infrared saunas heat you from the inside out. Thermal radiation directly heats your body. The surrounding air is not as hot in an infrared sauna as it is in a dry sauna. These far infrared emitters give off a similar wavelength as the sun.
Infrared saunas give you an energizing feel, like you get in sunlight. In contrast, a dry sauna usually drains you of energy. Infrared is fundamental to the function of your cells.
“Mitochondria are the engines of each of our cells and this infrared light provides them with extra energy.”
The humidity of an infrared sauna is very low. It’s just like a room in your home. There is no steam capabilities because there is no heater nor stones.
Many sauna traditionalist consider the infrared sauna to be a bastardization of a traditional sauna because it has no heater, no stones, no Löyly, and no aromas.
Infrared sauna fans point to the infrared saunas deep penetrating infrared heat. This enables a deeper sweat than in a traditional sauna. The deep penetrating heat and sweat is considered to be more detoxifying than a traditional sauna.
How hot is an infrared sauna?
An infrared sauna can be from 100-150. You will still feel hot and profusely sweat, despite the lower temperature.
There are ways to biohack your infrared sauna to make it hotter. I wrote an article about how Ben Greenfield does it here.
How long do you stay in an infrared sauna?
You can stay in an infrared sauna longer than a traditional sauna because the temperature is not as hot. Spa’s typically offer infrared sessions between 30-60 minutes.
It takes around 15 minutes to heat up. You can sit in the sauna for those 15 minutes or just go in when it is warm.