User:CD17/sandbox/Water-filtered infrared-A

Water-filtered infrared-A (wIRA) is a special form of heat radiation (infrared radiation, directly neighboring to visible light, especially red light, see figures) in the range 780-1400 nm and is used in clinical medicine for prevention and therapy. wIRA combines deep penetration property with only a small thermal load to the skin surface and therefore shows good tolerability and a wide range of clinical indications for the application of wIRA. Technically produced wIRA is derived from the filtering effect of water and water vapour of the atmosphere, causing the heat radiation of the sun in moderate climatic zones typically being perceived to be pleasant.

Natural wIRA
In moderate climatic zones, different to desert regions, the heat radiation of the sun is typically perceived to be pleasant without stinging or burning, as the heat radiation of the sun is filtered by water and water vapour of the atmosphere, by this decreasing infrared-B and the water absorption bands within infrared-A. These wavelengths would otherwise interact with water molecules in the upper layer of the skin and would cause a thermal burden to the skin, resulting in stinging or burning (Figure).

Technical wIRA
Technically wIRA is produced by special radiators, in which typically the whole broadband radiation of a 3000 Kelvin halogen bulb is passed through a water-containing cuvette in which the mentioned undesired wavelengths are absorbed or decreased. When using the same irradiation intensity (irradiance) wIRA results in lower skin surface temperature compared to unfiltered infrared radiation. When achieving the same skin surface temperature, a wIRA radiator can deliver nearly 4–9-fold infrared-A irradiance compared to unfiltered infrared radiators. Concerning special medically important wavelengths, like 820 nm, it can be even 6–30-fold.

Effects
The three main thermal effects of wIRA are: wIRA increases tissue temperature, tissue perfusion and tissue oxygen partial pressure markedly. The five main clinical effects of wIRA are: wIRA decreases pain, inflammation and hypersecretion, and wIRA improves the immunological status and regeneration.

Clinical applications
Therefore there is a wide range of clinical indications for the application of wIRA:   wIRA can be used to improve the healing of acute  and chronic wounds   (even the undisturbed “normal” healing of the wound can be improved: faster and with less pain). wIRA can as well be used in skin diseases (e. g. Herpes simplex labialis, Herpes zoster, common warts, sclerodermia, neurodermitis; within a photodynamic therapy in actinic keratosis), and for the improvement of the resorption of topically applied substances to the skin. Other indications  are musculoskeletal disorders (osteoarthritis, arthrosis, spondyloarthritis, lumbago, low back pain, fibromyalgia), regeneration after sports, combination with ergometer training, keeping or increasing temperature in neonatology, therapy of hypothermia; and in combination with radiation therapy or chemotherapy in oncology. In addition wIRA can be used in polyneuropathies and in complex reginal pain syndrome.

Basis of effects
The effects of wIRA are based on its thermal (referring to the transfer of heat energy) and thermic (temperature dependent) effects as well as on non-thermal and non-thermic effects like direct effects on cells, cell structures and cell substances. Decrease of pain and of inflammation and the improvement of infection defense and of regeneration can be explained both by thermal and non-thermal effects. Concerning pain reduction increased tissue perfusion improves elimination of pain mediators and together with increased oxygen partial pressure causes a higher metabolisation of pain mediators and a faster regeneration by a higher rate of energy production (caused by higher temperature, higher perfusion and higher oxygen partial pressure in the tissue). Decrease of hypersecretion/exudation can be explained by non-thermal effects. Concerning non-thermal effects the energy-rich wavelengths between 780 and 1000 nm seem to be the clinically most important wavelengths within wIRA. Non-thermal effects include effects on the cytochrome C oxidase in the mitochondria: cytochrome C oxidase is known as universal photo acceptor in the range approximately 600-1000 nm  and can start cascades of reactions with importance even outside energy production. wIRA in therapeutic irradiances and doses has been shown not only to be harmless to human skin,     but also to have cytoprotective effects.