We are well aware of the adverse effects of the sun’s radiation on our skin and blame ultraviolet light (UVA and UVB). To reduce its impact we use sunscreens and limit sunbathing. But the sun's infrared rays can also penetrate to the deeper layers of the skin.
Sunlight is composed of ultraviolet light (7%) and visible light (38%), but infrared (IR) light, at 54%, represents the most important fraction. Depending on the wavelength, IR radiation is classified into three types: IRA, IRB and IRC. Both UV and visible light are attenuated by melanin, a substance secreted in the top layers of skin. However, IRA rays can pass through to the deeper layers of the skin.
Do infrared rays affect us?
Although the adverse effects of IR radiation on health have not traditionally received much attention, IRA rays induce heat in the skin, sometimes over 40ºC. Studies reviewed by World Journal of Dermatology demonstrate that normal exposure to IRA rays stimulates the production of collagen and elastin, but an excess can cause skin changes similar to those caused by UV light, namely, inflammation, premature photoageing and even cancer.
Furthermore, excess IR radiation affects a number of biochemical mechanisms, producing reactive oxygen species (ROS) and altering the collagen balance.
But be warned! IRA rays don’t come just from the sun, but also from many electronic devices such as computers.
How to protect yourself from IRA rays
Sunscreens that protect against UV rays are not effective against IR radiation. Currently there is no commercially available specific chemical substance or sunscreen that protects against IRA radiation and any compounds that may be available have yet to prove their effectiveness.
A possible solution
Although there is some dispute about this, an alternative approach to photoprotection against IRA rays is the application of creams containing antioxidants, such as epigallocatechin gallate (found in grape seed extract and tea extracts), vitamin C, vitamin E and Q10 coenzyme derivatives.
According to Professor Jean Krutman, applying such topical antioxidants before exposure to IR radiation would decrease damage to the skin. Some commercial firms already add active antioxidants to sunscreens to slow down the action of IR rays, but more studies are necessary to definitively support the claims.
Another prevention strategy is to ingest antioxidants. ISRN Dermatology has published studies that demonstrate that oral antioxidants potentially slow down the damage caused by solar radiation.
In view of the ongoing revelations of science, the best way to keep our skin healthy is undoubtedly to do as people have done since ancient times: avoid excessive sunlight.