Infrared Light
Image Source (Posturepress)
What is it?
Infrared light is a type of Electromagnetic Radiation with a range of wavelengths from 700 nanometres to 1 millimetre. It is most commonly referred to as “thermal radiation” as it is produced by a body which possesses heat energy and is what the human body experiences when it senses heat. As will be discussed on the other pages of this website, all EM waves can heat bodies, however Infrared Radiation is closely linked to the effects of heating on a body. Every body emits energy as EM Radiation, however a body at the human body temperature of 37.5°C will produce most of its radiation in the form of Infrared Light. For this reason, infrared light is a useful tool for imaging in medicine. Its close association to heat also yields more therapeutic uses for this radiation.
Uses
Apart from this thermal radiation being capable of cooking a meal in the oven, it has some other very important uses! Infrared Light is commonly used in medicine to treat strained muscles and tissues. IR is close in wavelength to red light, however it penetrates the skin and tissues much deeper than any visible light and can therefore be used as an effective, non-invasive therapy.
A particular treatment which is used in hospitals is called “Near Infrared Light Therapy”. This therapy utilizes the penetrative power of the IR light and provides a dose of radiation to the cells of the sprained muscle or damaged tissues to be treated. This light excites the body’s metabolism and promotes blood flow and the movement of Oxygen around the tissue, which has been shown to relieve pain, reduce inflammation and encourage healing [IR1].
Another use for IR light is the role which it plays in medical imaging techniques. Thermography is a form of imaging which passively views the human body through a thermal camera, scanning it for changes in temperature which can tell us a lot about the health of a person and their tissues. It is commonly used the diagnose circulatory diseases and take scans of organs.
A full body Thermogram taken using a thermal camera. Image source (Meditherm)
Safety
Infrared Radiation is naturally occurring in the majority of instances in which it is used in medicine. Usually produced by the human body itself or something of a similar temperature, it is easy to see how this thermal radiation cannot be harmful the human body. Long exposure to heat treatments like Near Infrared Light Therapy may cause burning to the skin and it has also been shown to accelerate the aging process [IR3]. However, it is also used in cosmetics in small doses as a treatment to improve skin texture and reduce wrinkles [IR4].
A handheld LED device which is used in Infrared Light Therapy. Image source (RedLightTherapy)