What is Far Infrared?

Woman in a white dress standing in shallow water at the beach, arms outstretched towards a bright sunset, symbolizing freedom and serenity.

What exactly is Far Infrared? We’ve all experienced the penetrating heat of an open fire on a cold night, or the heat of the sun’s rays on our body when a cloud moves away. The penetrating heat you feel is Far Infrared.

An Infrared Sauna uses heater technology that emits a band of light we perceive as heat called Far Infrared. We cannot see this band of light with the naked eye, but we can feel this type of light in the form of heat. Our sun produces most of its energy output in the infrared segment of the spectrum. Infrared rays heat your body without having to heat the air in-between, through a process called conversion.

The infrared (IR) is divided into 3 segments by wavelength, measured in microns; near infrared: 0.75-1.5 microns; middle infrared: 1.5-4.0 microns; and far infrared: 4.0-1,000 microns. Among these segments, only far infrared penetrates organic substances such as the human body to 4-5cm so that the warming effect is very uniform.

Are Far Infrared Saunas Safe?

Far Infrared rays should not be confused with Ultraviolet (UV) Light which can cause sunburn and damage to the skin.

Even though exposure to the sun can be beneficial to the health, sunbathing must only be enjoyed in moderation because of this harmful UV ray. This is especially the case in New Zealand where damage to the ozone layer has intensified the dangerous UV rays.

On the other hand, Far Infrared rays are the part of the rays that make you feel warm when you sit in the sun and it is safe and healthy for all living things.

We can be exposed to Far Infrared heat for hours and it will never cause our skin to burn; it is not only safe but also highly beneficial to our bodies on a cellular level. Health professionals have used infrared heat lamps for decades to treat muscle and joint problems. In hospital baby care units, incubators are often equipped with infrared heating systems to keep newborn babies warm.

The Human Body Radiates Far Infrared

The sun is not the only source of Far Infrared. Even our body radiates FIR. Night vision goggles used by the military detect the Infrared Rays generated by the body. Approximately 50% of the energy generated by your own body is in the form of Far Infrared rays. Our bodies radiate Far Infrared energy through the skin at 2 to 50 microns, with most of this output being at the 4-14 micron level. The human body best absorbs infrared at approximately 4-14 microns. It then naturally follows that when FIR of this frequency range is used in therapeutic treatment, it will have the greatest beneficial effect on the patient. This is because it is the frequency best able to produce the warmth necessary to expand capillaries and stimulate blood circulation. Our Sun Stream infrared saunas emit waves at this optimum wavelength.

Far Infrared Sauna - How does it work?

A Far Infrared Sauna differs from traditional saunas as it uses infrared radiant energy to directly penetrate into the body’s tissue to produce sweating. Traditional saunas use steam to heat the air inside the sauna, which then heats your body until you begin to sweat. In order for this to be effective, temperatures reach upwards of 90 degrees. Infrared saunas only need a temperature of up to 48 degrees to obtain the same effect. This lower temperature makes the atmosphere more tolerable, while also allowing you to breathe easier. Activated by heat, an Infrared Sauna emits FIR energy that is absorbed by human cells, causing a physical phenomenon called “resonance.” Thus the cellular activities are instantly invigorated, resulting in a better blood circulation and an overall improved metabolism.
Comparison of infrared sauna (left) and conventional sauna (right), highlighting heat distribution, body positioning, and colors.
This colour isothermograph shows the effects of far infrared therapy. Infrared rays are highly efficient as heat is penetrated more deeply into the skin when compared to the traditional saunas. In fact, one needs fewer treatments or sessions when he uses an infrared sauna to get the same results as when he has more sessions in the traditional hot stone saunas.
Thermal imaging comparison showing body temperature changes before, during, and after FIR (Far Infrared) therapy. The image illustrates the heat distribution with a color gradient scale, highlighting the effects of FIR therapy on the body’s temperature.

What's the difference between Far Infrared, Mid Infrared and Near Infrared in a Sauna Application?

  • Far Infrared radiant heat is highly absorbed by the water content or moisture in our skin (1- 4mm depth), far Infrared is the appropriate wavelength for the purposes of a sauna; for a whole body radiant heat treatment, for raising your body’s core temperature, boosting your immune system and inducing a cleansing detoxing sweat.

  • Mid Infrared is not well studied and outside of the advertising from certain ‘full spectrum’ infrared sauna companies we have been unable to find any information indicating particular benefits of MIR which makes up a very small portion of the light spectrum (only 1.4- 3.0 microns). Mid Infrared is likely absorbed by the water content in our skin as is Far Infrared and can add to the heating effect of the sauna.

  • Near Infrared produces little heat and therefore is not fit for the purposes of sauna, it has a low absorption rate and a high reflection rate which means that emitters need to be placed in close proximity to the skin to overcome the skin’s natural defence mechanism. Once this is achieved NIR passes through our tissue where several biochemical reactions occur associated with cellular energy production and healing.