Infrared full-spectrum sauna (IR-A, IR-B and IR-C) – physics, tissue penetration and biological mechanisms
Infrared sauna is a technology that uses electromagnetic radiation in the infrared range to transfer energy to biological tissue. Unlike traditional saunas, which mainly heat the air, infrared systems transfer energy directly to the body. An infrared full-spectrum sauna combines several parts of the infrared spectrum and thus differs from simpler solutions that only use one type of infrared radiation.
What is meant by infrared full spectrum sauna
The term full spectrum refers to the use of several infrared wavelength ranges at the same time, usually IR-A, IR-B and IR-C. These areas have different physical properties and different tissue penetration. A full-spectrum sauna is designed to cover a wider spectral range and thus provide more varied energy transfer than saunas that only use far infrared light.
The infrared spectrum: IR-A, IR-B and IR-C
Infrared radiation is usually divided into three main areas. IR-A is closest to visible light and has wavelengths approximately from 700 to 1400 nm. IR-B is located in the area approx. 1400 to 3000 nm, while IR-C covers the range from around 3000 nm upwards. These areas have different absorption patterns in biological tissue, mainly determined by water content, blood and tissue structure.
IR-A has the deepest tissue penetration and can reach several centimeters into the tissue. IR-B has more limited penetration and is absorbed to a greater extent by the surface. IR-C is almost completely absorbed in the skin's top layer and primarily contributes to surface heat.
Tissue penetration and heat transfer
One of the most important differences between the infrared ranges is how the energy is absorbed in the body. IR-A can penetrate relatively deeply and contribute to the heating of deeper tissues. IR-B provides a combination of surface and medium-deep heating, while IR-C mainly provides rapid heating of the skin surface. In a full-spectrum sauna, these areas work together and create both a local and more profound heat load.
The heat transfer occurs mainly through direct absorption of infrared energy in the tissue, in contrast to convective heating via hot air. This provides a different physiological experience than in traditional saunas.
Biological responses to infrared heat
When biological tissue absorbs infrared energy, the temperature increases locally. This can affect circulation, tissue elasticity and metabolic processes. The heat can lead to increased blood flow in the skin and underlying tissue, as well as activation of temperature-regulating mechanisms in the body. These responses are general physiological reactions to heat and not specific to a single wavelength.
In full-spectrum systems, various infrared components are combined to create a more varied thermal stimulus, where both superficial and deeper tissues are exposed to heat energy.
Sunlighten mPulse smart infrared sauna - front and glass door
The difference between traditional infrared sauna and full spectrum
Many infrared saunas only use IR-C, often referred to as far infrared light. This provides effective surface heating, but limited tissue penetration. An infrared full-spectrum sauna additionally includes IR-A and IR-B, which provides wider spectral coverage and a different distribution of heat in the tissue. This is a technical difference in how the energy is delivered, not just in how hot it feels.
Use and practical considerations
Using an infrared full-spectrum sauna involves exposure to heat over a given period of time. Temperature, exposure time and individual tolerance vary. Modern systems are designed with a focus on controlled heat release, safety and comfort, and are supplied with the manufacturer's recommendations for use.
Conclusion
Infrared full-spectrum sauna represents a technological approach where several parts of the infrared spectrum are combined to provide wider and more varied heat transfer to biological tissue. By using IR-A, IR-B and IR-C at the same time, both superficial and deeper tissue layers can be exposed to infrared energy. This distinguishes full-spectrum saunas from simpler infrared solutions and provides another biophysical starting point for heat exposure.
About Uno Vita's editorial staff
This article has been prepared by Uno Vita's specialist editorial team and is based on available scientific literature, technical documentation from manufacturers and Uno Vita's experience with infrared, light and electromagnetic technologies. The content is intended as general professional information and should not be understood as medical advice, diagnosis or treatment. Uno Vita AS works with integrative and technology-based solutions in areas such as photobiomodulation, infrared technology, hydrogen and oxygen systems, PEMF and frequency-based systems. In the case of health complaints or medical questions, it is always recommended to contact a qualified healthcare professional. Freedom of expression and professional dissemination of biophysical principles are central to Uno Vita's information work.
Scientific references
Vatansever F, Hamblin MR. Far infrared radiation (FIR): Its biological effects and medical applications. Photonics Lasers Med. 2012.
Yaroslavsky AN et al. Optical properties of human skin and subcutaneous tissues. J Biomed Opt. 2002.
Hershler C. Infrared and thermal physiology. J Appl Physiol. 1991.
Boulant YES. Role of the preoptic-anterior hypothalamus in thermoregulation. J Appl Physiol. 2000.
Schneider M et al. Infrared radiation and tissue heating mechanisms. Phys Med Biol. 2019.
