Infrared heaters and your health
I have no first hand experience with infrared (IR) heaters in saunas. Since my expertise and bias lies with the Finnish sauna, take the following with a grain of salt.
How does infrared work?
In an IR sauna an infrared radiator is used to send heat directly to the skin of the bather in the form of radiated heat (infrared electromagnetic radiation, essentially the same kind of radiated heat we get from the sun or a hot lightbulb). This radiation is invisible to the naked eye. It is also entirely harmless - as a matter of fact, just about everything radiates infrared waves, in more or less intense ways.
When infrared rays hit your skin, they transfer heat energy to it. Your skin temperature goes up and you react by starting to sweat.
By comparison, the traditional Finnish sauna uses a combination of radiation, conduction and convection to transfer energy to the bather's body (from the heater's stones and the room's walls, from the löyly and from the airflow, respectively).
How does it affect you?
The health benefits usually claimed (for both kinds of saunas) include improved blood circulation and hence a stronger cardiovascular system, a cleansing of the body, and finally loss of weight. Few of these health benefits have been proven beyond doubt. You will find my opinions on these claims on the page discussing health issues. Although I am sceptic about many claimed benefits, the truth is that many people enjoy their saunas and feel better after using them.
Locally administered infrared is used as treatment for some skin diseases and tissue traumas with varying success. The most successful use so far seems to be the application of infrared rays to help ease the joint pain and stiffness of arthritis patients. Here infrared has several benefits over conductive heat transfer (hot wrap etc). Infrared radiation penetrates the skin while it is being absorbed. In effect, it heats the skin and muscle tissue from the inside. This is very much a benefit for arthritis patients, whose pain is often very localised.
Although infrared rays are the same kind of electromagnetic waves as light, microwave, UV or x-rays, you have very little to fear. Unless you are given painfully strong levels of radiated heat, your skin is entirely ok with it. Remember that the heat we feel from the sun is infrared radiation and we're ok with that as well.
Thorough studies on the effects of infrared radiation remain hard to find. If you encouter something interesting in a perr-reviewed journal, please let me know about it.
Readers' comments
There are many who enjoy the IR saunas, so you should probably try it out before deciding one way or the other. Here are some comments from a US reader:
"The IR heater needs about 10 minutes for the tubes to get warm enough to start to work. The sauna gets warmer as you sit in it.
Last night I started sweating at a pretty low temp. In 45 minutes the sauna was at 122 degrees [50° Celsius] and I must have lost a gallon of water. The way the thing penetrates your body is absolutely amazing. (Literature says the IR penetrates the skin approx 1 1/2 inches) I wasn't a believer until I tried it.
It doesn't neet the higher heat of the traditional sauna to do the job just as well. I have mine set to turn off at 135 [57° C]. It will go up to 150 [65° C]. At those temps, the effect is just as a traditional sauna. It's doing wonders for my asthma, and that is an effect I didn't plan on."
Another reader from Estonia tried out his first IR sauna with two of his freinds:
"We were advised to drink at least 0.5 liters of water before the sauna. The manager set the temperature to 55 degrees [130° F] after consulting with us (55 degrees is a *lot* and is generally NOT recommended for somebody who has not had experience with saunas all their life long). We were told that the maximum that the given sauna would operate on was 60 degrees. She set the time to 40 minutes, which would be a lot for beginners as well.
We were given a liter of fresh lemon-flavored water into the sauna and were advised not to walk in and out of the sauna (we should sit there the entire time, not as in the traditional sauna, where you walk back and forth many times). For the record -- it is always necessary to come out of any kind of sauna, whether traditional or IR sauna, when you start feeling bad or nauseous!
That liter of water was perhaps not enough for three persons (the manager originally only expected me) and you should drink a lot more. You start sweating like a pig right from the start! And you sweat a lot! The IR sauna penetrates deep under your skin and is pretty pleasant, actually.
That all being said -- nothing can beat the good old traditional sauna that is being heated with birch. You also need some good friends and a nice lake nearby."