IR Saunas and 5G: Comparing EMF Exposure

Both are forms of radiation and thus sources of EMF exposure. The results of this comparison are counterintuitive and intriguing.

Photo by Terry Vlisidis on Unsplash

Due to the therapeutic benefits being claimed, treatments via infrared (IR) saunas are increasing. As such, there are a growing number of publications and articles (such as this one) explaining the technology and its potential. The Mayo Clinic states the following regarding IR saunas:

“An infrared sauna is a type of sauna that uses light to create heat. This type of sauna is sometimes called a far-infrared sauna — “far” describes where the infrared waves fall on the light spectrum. A traditional sauna uses heat to warm the air, which in turn warms your body. An infrared sauna heats your body directly without warming the air around you.
The appeal of saunas in general is that they cause reactions similar to those elicited by moderate exercise, such as vigorous sweating and increased heart rate. An infrared sauna produces these results at lower temperatures than does a regular sauna, which makes it accessible to people who can’t tolerate the heat of a conventional sauna. But does that translate into tangible health benefits? Perhaps.” -Mayo Clinic, Brent A. Bauer, M.D.

As stated above, IR saunas are commonly called far-infrared (FIR) saunas, and the term “far” refers to the IR wave’s location on the electromagnetic spectrum. More specifically, the term far refers to the wave’s frequency and wavelength, which are inversely related. As the wavelength (distance between peaks or troughs) of an IR wave gets longer, its frequency decreases, and it is said to “move farther into the IR spectrum.” If the IR wavelength gets long enough, it moves into the microwave slice of the electromagnetic spectrum. This is where fifth generation (5G) wireless communication technology comes into play.

As we will look at in more detail below, 5G technology operates right next to FIR on the electromagnetic spectrum — they’re neighbors. FIR and 5G are both sinusoidal waveforms of electromagnetic radiation or electromagnetic fields (EMF). These terms are synonymous with light, so we can refer to FIR and 5G as light waves. At a minimum, a light wave must contain one photon. The only difference between FIR and 5G waves are their respective photon frequencies.

With its lower frequency, 5G is a less energetic light wave, whereas FIR is, actually, a more energetic light wave. When comparing a single photon of each, this means the EMF exposure from FIR is higher than 5G. Given the recent warnings (see here and here) about the potential dangers of 5G, and other forms of wireless communication (e.g., Wi-Fi, 4G-LTE), to humans due to EMF exposure, the previous statement might sound counterintuitive. One might expect 5G to be more energetic than FIR, but this is incorrect. 5G is, in fact, a less energetic light wave than FIR. But how then can FIR be potentially therapeutic and 5G allegedly hazardous?

Answering this question is multifaceted, and it’s your author’s opinion that more research needs to be done on each technology before conclusions can be drawn. The purpose of this article is to begin answering this question by starting with the fundamentals at a physics level. We must first understand how the two light waves compare; we need to not only look at relative energy but also power (energy per unit time) to help us quantify how much energy a surface (e.g., a person’s body) is exposed to over a given time — understanding exposure is key.

For an introduction to EMF, light waves, and invisible exposure to humans, reference “Demystifying EMF.” The referenced article introduces and explains, in greater detail, the terms used herein: electromagnetic spectrum, EMF, light wave, photon, frequency, energy, power, and intensity.

EMF Energy Comparison

Let’s start by identifying where FIR and 5G are located on the electromagnetic spectrum. In the figure below, locate ‘infrared’ (FIR) and ‘microwave’ (5G):

Comparison of Wavelength, Frequency, and Energy for the Electromagnetic Spectrum (Credit: NASA’s Imagine the Universe)

The figure above is particularly useful because it illustrates how wavelength, frequency, and energy are related.

Rule-of-Thumb #1: To determine which light wave has more energy for a single photon, simply look at the frequency — the energy is proportional to frequency. If the frequency of a light wave increases, then the energy increases as well and vice versa.

Example #1: If light wave A is a radio wave and light wave B is an x-ray, then light wave B has higher energy because its frequency is higher.

Frequency Relation for the EMF Spectrum
Energy Relation for the EMF Spectrum

Rule-of-Thumb #2: To determine which light wave has more energy for a single photon, simply look at the wavelength — the energy is inversely proportional to wavelength. If the wavelength of a light wave increases, then the energy decreases and vice versa.

Example #2: If light wave A is a radio wave and light wave B is an x-ray, then light wave B has higher energy because its wavelength is shorter.

Before calculating the amount of energy for FIR and 5G, we’ll start by identifying the frequency band for 5G:

5G* Networks: 30–300 GHz

*5G technology is currently in development and is only being introduced in select regions. It is also referred to as “millimeter wave” technology which refers to the wavelength of light waves with frequencies between 30 and 300 GHz. For more information on 5G/millimeter wave technology, reference the video and article by the Institute of Electrical and Electronics Engineers (IEEE) and this video by Seeker.

Next, in order to specify the IR wavelength bands, we can reference an IR study, which specifies the near-infrared (NIR), mid-infrared (MIR), and FIR wavelengths as follows:

“The infrared segment of the electromagnetic spectrum is divided into three segments by wavelength, measured in microns or micrometers (1 micron = 1/1,000,000 of a metre); 0.076 ~ 1.5 microns = near or close; 1.5 ~ 5.6 = middle or intermediate; 5.6 ~ 1,000 = far or long wave infrared.” -M.E. Habib, T. Punnoose, and C. Thomas. “Deep Burns Caused by Far-Infrared Rays in a Chiropractic Sales Centre”

Near-Infrared (NIR): 0.7* ~ 1.5 micrometers (microns)

Mid-Infrared (MIR): 1.5 ~ 5.6 micrometers (microns)

Far-Infrared (FIR): 5.6 ~ 1000 micrometers (microns)

*The referenced study includes wavelengths down to 0.076 micrometers (76 nanometers). For the purposes of this discussion, this range has been clipped at 0.7 micrometers (700 nanometers). Visible red light is approximately 700 nanometers and visible violet light is approximately 400 nanometers. Therefore, the NIR range is assumed to start at 700 nanometers, which is when the wavelength of visible red light is on the threshold of what the human eye can see.

As a side note, the above study addressed a specific case where a patient received a burn from an IR treatment. The authors of the study issued an IR safety warning alongside an acknowledgment of the benefits:

“We recommend medical supervision in such centres and strict adherence to safety precautions. … A narrow spectrum between 14 and 4 microns has been shown to have particularly beneficial effects on the body. … We cannot precisely perceive the deep heating effects of FIR because our body’s ability to sense heat functions mainly at skin level.” -M.E. Habib, T. Punnoose, and C. Thomas. “Deep Burns Caused by Far-Infrared Rays in a Chiropractic Sales Centre”

Referencing the wavelength bands for IR (above), equivalent frequencies can be determined by using the wavelength relationship below:

Wavelength Equation

Now that we have both FIR and 5G in terms of frequency, we can swiftly calculate the energy using the Planck Equation:

Planck Equation

Below are the results of the process outlined above. It provides a summary for 1) the energy levels of a single photon and 2) provides a relative EMF energy comparison:

EMF Energy Comparison

When compared to 5G technology at 30 GHz, we can make the observation that IR waves output 1,783 times to 14,267 times the amount of EMF energy per photon. Obviously, the energy of one photon is useful to know, but what we really care about is power and the amount of exposure a human would receive.

EMF Power and Exposure Comparison

Power is defined as energy per unit time. This can tell us how much energy a surface (e.g., a person’s body) is exposed to over a given time.

Power Equation

To begin, we have to gather technical specifications on IR saunas and 5G technology devices. After a quick, non-exhaustive search (reference here and here), it was found that IR saunas have a power rating of approximately 1200 Watts (W) on the low end and 5200 W on the high end.

Due to its smaller wavelength compared to 4G-LTE and others, one of the concerns with 5G is that the millimeter waves will be blocked by obstacles (e.g., buildings) that are not an issue with existing technologies. To remedy, small cell sites will need to be distributed locally to help relay the signal. As a result, there is a concern that these small cell sites will create hazardous EMF levels. Therefore, it’s reasonable to select the small cell sites as the 5G device to be used for comparison purposes. Seeker reported that these small cell sites will have a power rating of 2–10 W.

In addition to the above, the following assumptions were made:

  1. 100% of EMF energy emitted by the light source (FIR or 5G) is absorbed by a human.
  2. Exposure time from an IR sauna will be a maximum of 0.5 hours per day — a human won’t likely sit in a sauna for longer than thirty minutes.
  3. Exposure time from a 5G device will be 24 hours per day — the device will always be on.
  4. For simplicity, the small cell sites are assumed to be located in a room where a human would be. In reality, small cell sites will likely be located outside without any loss in performance (latency). This is, therefore, a conservative assumption; in particular, when you consider that EMF intensity is inversely proportional to the distance squared.

Rule-of-Thumb #3: Intensity is inversely proportional to the distance squared. Light intensity decreases as the distance between your body and the light source increases.

Example #3: If you double the distance between yourself and a given light source (small cell site, Wi-Fi router, etc.), the intensity decreases by a factor of 4. Triple the distance and the intensity decreases by a factor of 9 and so on.

Utilizing the FIR and 5G power ratings and assumptions above, the summary below was generated:

EMF Power and Exposure Comparison

Even with overly conservative assumptions for the 5G small cell sites, we can see that the relative EMF exposure from an IR sauna is 13 times to 54 times more per day. A reasonable follow-up question is:

“What will the power output and exposure from a 5G smartphone antenna be?”

Even though the technology is still in development, your author attempted to look up Qualcomm’s, the United States (U.S.) leader in 5G hardware, 5G radio frequency (RF) antenna power output, but the information wasn’t available online. As a workaround, the site for the U.S. Federal Communications Commission (FCC) was referenced. The FCC states the following in regard to Specific Absorption Rate (SAR):

“Working closely with federal health and safety agencies, such as the Food and Drug Administration (FDA), the FCC has adopted limits for safe exposure to radiofrequency (RF) energy. These limits are given in terms of a unit referred to as the Specific Absorption Rate (SAR), which is a measure of the amount of radio frequency energy absorbed by the body when using a mobile phone. The FCC requires cell phone manufacturers to ensure that their phones comply with these objective limits for safe exposure. Any cell phone at or below these SAR levels (that is, any phone legally sold in the U.S.) is a “safe” phone, as measured by these standards. The FCC limit for public exposure from cellular telephones is an SAR level of 1.6 watts per kilogram (1.6 W/kg).” -FCC

To provide a quick calculation, let’s assume a smartphone user weighs 68 kg (~150 pounds). This equates to ~109 W (1.6 W/kg * 68 kg) of exposure.

Takeaways

Though it may not be readily known by the general public, FIR and 5G are located next to each other on the electromagnetic spectrum. Counterintuitively, IR saunas appear to result in more EMF exposure than some 5G hardware (i.e., small cell sites), and when compared to 5G, FIR is a higher EMF energy light wave. Knowing that EMF exposure from IR could be substantially higher than 5G under certain conditions is worth noting and investigating further. More research is needed on FIR and 5G to fully understand the potential health benefits and risks.

Final Thoughts:

What will happen if the next generation of wireless communication technology after 5G (call it 6G or whatever) moves into the FIR portion of the electromagnetic spectrum? Will the new technology have some therapeutic benefits like FIR, or will it be considered potentially hazardous like 5G?