Update on Sauna

A recent post by Dr Mercola raised interesting questions about sauna safety

We discussed the benefits of sauna in a post last year. More recently, Dr Joseph Mercola posted some information on this that piqued my curiosity — in addition to strong recommendations to use sauna regularly, for a lot of health benefits, he advises of some risks. I did a test at my gym’s sauna and found mine is safer than his. Maybe yours isn't.

Dr Mercola is a prolific writer on a range of health and medical issues and is highly recommended to follow. You can find him at mercola.com, drmercola.substack.com, or his subscriber site at takecontrol.substack.com.

He posted May 8th on saunas on his subscriber substack, and again on Oct 15 emphasizing possible risks from traditional “Finnish“ or far infrared saunas, which use a heater in an enclosed space, usually electric in modern saunas. Another type is near infrared saunas, which heat your body directly instead of the air and furniture. Like a microwave oven, but with a safer frequency.

Infrared is a color of light, slightly lower frequency than what we see as red, but outside the detection capabilities of our eyes. But you can feel its effects by the warming of your skin with sufficient power. Everything emits infrared light, and some animals can detect it, but we can’t without help. It is useful for things like night vision goggles and security cameras, and the amazing new James Webb telescope that can see through dust clouds to see things we can’t see in visible light. Sunlight is a strong infrared source, and we evolved biologically to need regular doses to produce things like Vitamin D, and melatonin, and a variety of photobiomodulation (PBM) activities in our bodies. People who don’t get enough sunlight get sick more.

Traditional saunas use a heater that puts out heat mainly in the far infrared spectrum. It heats the air, the furniture, and our bodies. Near infrared saunas are a newer design and produce less detectable heating because it doesnt interact with air or hard objects, but does heat our bodies down to a couple inches deep. Near infrared is the part of the light spectrum just below (lower frequency) the visible portion that our eyes can see. Slightly lower frequencies in the infrared range are called far infrared, and doesn’t affect the PBM functions as much as near infrared. But much of the benefit of any sauna, such as heat stress and detoxification, comes from the heating effects, which comes with all parts of the infrared spectrum.

Dr Mercola seems interested in the increasingly common people who don’t really get outdoors much, or cover their skin when they do, and thus get less sun exposure on their skin. He suggests near infrared saunas as a replacement. More conventional far infrared saunas provide the beneficial heat and detoxification, but the necessary PBM benefits need to be gained from exposure to sunshine. I like to spend time outdoors, so I probably don’t gain much from near infrared sauna. If you don’t get out much, a near infrared sauna might be more beneficial than traditional saunas.

The possibility of sauna risk comes from the emission of electromagnetic fields (EMF). EMF is a natural part of physics that affects everything we see. There are two components to EMF radiation, voltage and current. They vary in proportion according to the electrical resistance they encounter. I invite you to study physics or electrical engineering for more details, but for our purposes it’s sufficient to say they cause oxidative stress in our cells, altering our biology. It’s bad to get too much. But we’re exposed to it constantly in varying amounts. Cell phones are a major contributor, especially when we hold a transmitter beside our brain for extended phone calls. Power lines emit strong fields and people who live near them have reported a lot of unusual illnesses for decades. The wifi in our homes, businesses, coffee shops, everywhere we go. Your TV. Microwave ovens. “Wall wart” power supplies. And, of course, electric sauna heaters which convert 20 or 30 amps of electricity to glorious heat. Everything emits EMF. We’re surrounded by it, and it increases with every new machine we create.

So, how much is detrimental? I got a tester from Amazon for about $40 which reports danger at a level of 40 volts per meter of voltage, or 0.40 microTeslas of current, changing the screen to red when either condition is encountered. These photos show the tester near my microwave with high current, and by my wifi router with high voltage, suggesting I should be more careful in those areas. In both cases, backing away a few feet reduces it back near zero, with a more pleasant gray screen.

In the sauna, I measured zero throughout the room, most importantly on all the benches. The offender was predicted to be the heater, so I moved closer. The sauna in my gym is a room about 10 feet by 15 feet, with the heater in the corner and benches on the opposite wall. The heater is protected by a wood fence, and the heater itself is a metal cube on the floor, about two feet on each side. I measured at waist level and saw a voltage about one ot two volts and zero current. Above waist level was zero. Moving down to the floor it rose to red levels right beside the fence, but quickly fell to zero a foot or two away. Probably the heating coils are near the bottom, and emit the most EMF. The steel case might also shield bystanders from the EMF emissions.

Note that electromagnetic field strength fades with the square of the distance, so a field at one inch will be one fourth that level at two inches (twice the distance, squared), one sixteenth at 4 inches, and so on. Distance is a good defense.

So the short version of this tale is my cheap tester says the sauna in my gym is safe. Maybe yours is, too, but it deserves a check.

I do have some mysterious hot spots in my house. I’ll report on them as I learn more. For now, I think I’ll walk in the sunshine to my nearby gym for a workout and some sauna time.