Resonant Absorption - The Physics and Physiology of how Infrared Saunas Work

RESONANT ABSORPTION

HOW A FAR-INFRARED SAUNA WORKS ON THE HUMAN BODY

Shopping for a far-infrared (FIR) sauna can be overwhelming to those who are not familiar with how they really work and the benefits a FIR sauna can provide. There are dozens of companies and dealers selling them now and they all claim to have the best heaters and effectiveness. But… how do you know which one is the most effective sauna at the best price if you don’t understand how they work?

The purpose of this article is to help you understand what really is the most important factor in choosing an infrared sauna – what is called “resonant absorption”. So, for the moment, forget everything you have seen, heard or read about all the FIR saunas on the market and take the time to read and really understand how an FIR sauna really works. The effectiveness of an FIR sauna has to do with physics and physiology, not unproven claims on a FIR sauna dealer’s web site.

WHAT IS FAR-INFRARED HEAT?

Ever since the formation of the earth billions of years ago, protein, water and far infrared rays have enjoyed a harmonious relationship. Together they became a basic source of life support. An examination of the energy spectrum reveals that right beside the visible red light, there exist a longer radiative wave that has a strong heating effect – this wave is the far-infrared ray. A far-infrared ray is an electromagnetic wave that is reconverted into heat once it reaches a target.

Far-infrared rays have the following characteristics:

1. They cannot be seen with the naked eye

2. They exhibit features of light such as traveling in straight lines, but they can be deflected or reflected with the appropriate surface

3. They generate heat when absorbed by many substances

4. They penetrate many objects including human tissue

The human body consists of a huge range of organic and some non-organic substances, which in turn are composed of atoms and those of their constituent electrons, protons and neutrons, etc., which vibrate according to their own rhythms. When heated by far-infrared rays with the same harmonious vibration rhythm, some atoms become absorptive. When this phenomenon occurs, tremendous energy is generated within a molecule of which the atom is a part, some raise the activity (energy) level of the molecule, but most of the energy generated is in the form of heat.

Far-infrared rays with a wavelength between 7-13 microns in length can reach the earth through the “atmospheric window”. In view of this, it is only natural that the skin of the human body is more susceptible to these wavelengths. In addition to their ability to penetrate, far-infrared rays also have the property of resonance and absorption. When FIR waves enter the body, they are changed in form to become thermal energy. This penetration function enables far-infrared rays to pass through the skin to reach the deeper tissues and structures of the body to generate heat. Far-infrared rays are capable of penetrating the soft tissue to reach bone. Bones are themselves ceramic-like in composition and, when heated, can generate far-infrared rays.

The natural resonant frequencies of molecules of water and organic substances are within the FIR wave frequencies; therefore, water and organic substances absorb energy easily from this radiated FIR wave. Since it is their resonant frequency, they vibrate vigorously at that frequency and become the radiator of the frequency as well as the receiver.

The ability of an object or the human body to radiate and absorb FIR waves is determined by the surface temperature of that object. The ideal length of the FIR waves generated and absorbed by the human body is within a range of 8-14 microns. Our skin radiates 9.36 micron FIR wave since our body temperature is 97.7 degrees. That is very close to the resonant frequency of a water molecule and it makes sense since about 70% of our body is water.

When a molecule meets FIR rays of a certain vibration cycle (resonant frequency), the springs in the molecule that have the same vibration cycle will absorb the energy of the FIR rays, causing the springs to strongly contract and expand. This phenomenon is called “resonant absorption”. If the molecule does not have springs of the same vibration, it cannot absorb the rays and will simply pass through the molecule and impart no energy.

UNDERSTANDING THE EFFECTIVENESS OF FIR HEATERS

Now that you now understand how FIR waves affect the human body, let’s start looking at the different FIR heaters used in the various FIR saunas available. Every company says their heater is the best – which one really is?

The most ideal FIR wavelengths emitted by an FIR heater are those that not only have the property of resonance, absorption, and penetration, but also radiate evenly, and, through their undying wavelengths, penetrate to varying depths.

The longer the wave is, the deeper it can pass into the body. Many people thus believe that the longer a wavelength, the better. However, this perception is incorrect. In view of the properties of resonance and absorption, the body needs FIR of different wavelengths. Longer waves cannot perform the function of resonance and absorption in an area close to the surface of the body.

Therefore, it is vital that the FIR sauna’s heater can radiate both long and short FIR wavelengths. How do you know if the heater of the sauna you are considering to use produces both long and short wave? By measuring the surface temperature of the heater.

The FIR micron output of all FIR heaters are produced in a sine wave: in other words, the wave starts out low, rises to a peak and then lowers down. It is the peak that we are most concerned about as it is the bulk of the FIR energy that is produced by the heater.

The peak is determined by measuring the surface temperature of the heater and converting to its corresponding micron level through a law of physics called Wein’s law. This law states: the higher the surface temperature of the FIR heater, the closer the peak is to the shorter wavelength while the lower the temperature is, the closer the peak is to the long wavelength. From a practical perspective, an increase in the surface temperature of the FIR wave radiation media will generate a larger amount of radiation energy. As a result, the peak of radiation moves towards a shorter wavelength.

Please remember these two key points:

1. the ideal length of the FIR waves generated and absorbed by the human body are within a range of 8-14 microns.

2. since the human body resonates and absorbs FIR waves best in the 9-10 micron range (due to our body surface temperature of 97.7 degrees), it is vital that for maximum effectiveness on the human body, the FIR heater must have a peak output in this 9-10 micron range.

The FIR micron range is broken into three segments: near-infrared (0.75 to 1.5 microns), middle-infrared (1.5 to 5.6 microns) and far-infrared (5.6 to 1000 microns). In general, any FIR output below 5.6 microns is not beneficial to the human body. The micron range of most FIR heaters start out at 3-4 micron, rise to a peak and come down to finish out about 20-40 microns.

Now let’s look at the different FIR heaters used in FIR saunas. They mostly come in four different types – incoloy rod, ceramic-encased incoloy rod, ceramic-coated aluminum plate and organic carbon. Specific characteristics of each heater are:

1. Incoloy rod – shaped in a straight tube of about 26 sq. in. of effective surface area or formed into a “U” or “M” shaped tube to increase effective surface area to about 48 sq. in. – typical surface temperature is around 400° to 500° - converted by Wein’s law, peak micron output is around 6 microns – produces mostly short wave and very little long wave FIR.

2. Ceramic-encased incoloy rod – the most common used heater in low-priced FIR saunas – shaped in a straight tube of various length or ceramic plate mounted with a metal reflector behind it – typical surface temperature is 500° to 700° - converted by Wein’s law, peak micron range is 4-6 microns – produces mostly short wave and very little long wave FIR.

3. Ceramic-coated aluminum plate – rectangular-shaped plate with ridged surface to disperse FIR waves – surface temperature around 200° to 300° - converted by Wein’s law, peak micron range is around 7-9 microns – produces both long wave and short wave FIR.

4. Carbon – large rectangular-shaped panels – surface temperature around 100° to 200° - converted by Wein’s law, peak output is around 8-10 microns – produces both long wave and short wave FIR

SUMMARY

Now, start thinking about all of the types of heaters in all of the different FIR saunas you have seen. Notice that most FIR sauna manufacturers use the rod heaters mounted in metal reflectors. And, most of those are the $1500-$2500 low-budget saunas. There is a reason these FIR saunas are inexpensive – they use inexpensive rod heaters that have high surface temperatures and have low peak micron output that does not provide “resonant absorption”. You can save money and you will sweat but without “resonant absorption”, it will not be very effective in releasing toxins from your body.

Now notice that the FIR saunas in the higher price ranges use the larger heaters. There is a reason they cost more money. These FIR saunas use a larger heater that produces lower surface temperature and have a higher peak micron output that provides “resonant absorption” of FIR waves. They do not sacrifice quality and effectiveness to compete with the low-budget saunas.

Now notice one very important fact – all FIR sauna manufacturers and dealers say their heater is the best… but only one of them has ever published the specifications, heater surface size or surface temperature of their heater. These FIR sauna manufacturers really don’t want you to know that their heater is not that effective… and most shoppers don’t know the difference. Now that you have taken the time to read this article, you now know the difference and you need to ask yourself an important question:

You can spend $1500.00 on a sauna and you can spend $3500.00 on a sauna. Knowing what you now know… do you want to save money or do you want effectiveness. Because it is obvious – you cannot buy a low-budget sauna and have it effective on the human body. Physics and physiology beat marketing claims every time.

OTHER FACTS ABOUT FIR HEATERS

It is very unfortunate and sad that most sauna manufacturers and dealers use fear tactics and slander to convince their prospects that their FIR heater is better their competitors. Some are saying that a competitor’s heater can “outgas” and expose you to various substances such as aluminum, lead, carbon, silicon or sulfur. Notice how these companies never produce any independent proof to substantiate their claims? They are just trying to make people afraid to consider any other competitor. The reality is that any type of FIR heater and the various elements used in their construction will not expose you to anything harmful. We have the independent lab test results to prove it.

Another claims made is that some heaters heat up faster than other and that will make the sauna ready faster. Some say their heater is ready in 2 minutes. The reality is all FIR heaters are hot in two minutes and no matter which sauna you buy, all of them take 15-20 minutes to get up to around 100°.

REFERENCES

To research heater specification: www.tempco.com

Holistic Handbook of Sauna Therapy - Nenah Sylver

Reverse Aging – Sang Whang

The Scientific Basis and Therapeutic Benefits of Far-Infrared Ray Therapy – Sasaki Kyuo

This article was written by Wayne Franson, NCTMB www.backandbodysolutions.com