Light absorption is the first step in any photochemical process. When the photon is absorbed, the electron becomes energetically active enough to be pushed from the inner orbit to the outer one. As a result, the molecule goes into an "excited state".
Because of the limited number of orbits of a particular energy level in which electrons can exist, any given atom or molecule can only absorb light of a certain wavelength.
Humans emit IR photons that can be detected and identified. Their power is about 50-100 W. Radiation is a consequence of chemical (photochemical) processes in the body. Any pathological processes cause a change in the energy state of an organ, its part or the whole organism. Understanding the essence of these processes, we can adjust them using certain wavelengths.
The wavelength of IR radiation for medical applications must have a quantum energy no higher than that produced by a person himself, because otherwise unwanted harmful processes may occur. At the same time, it should be such that it can be used to equalize the rates of photochemical processes of the body, normalize immune processes, dissolve pathological formations (for example, collagen, atherosclerotic plaques, etc.), as well as destroy bacteria, fungi and viruses.
IR saunas use a method based on the normalization of exchange and elimination of pathological processes by IR - an influence that is in resonance with the processes that need to be corrected. In other words, IR radiation normalizes the metabolic process and eliminates the cause of the disease, not just its symptoms.