The infrared lamp for alleviating joint pain?

Invisible to the naked eye, the infrared light is part of the electromagnetic spectrum, just beyond visible red. It is generally divided into three categories according to wavelength: near infrared (from 700 to 1400 nm), mid-infrared (from 1400 to 3000 nm), and far infrared (beyond 3000 nm). In the context of medical or domestic devices, such as infrared lamps, it is primarily near and mid-infrared that are used. This light is distinguished by its ability to penetrate the skin deeply, much more so than UV or visible light. It interacts with tissues by producing a gentle heat that can reach the dermis, muscles and sometimes even the joints, thus having a soothing effect on pain.

Indeed, when it is absorbed by the tissues, the infrared light causes a localised increase in temperature. This in turn induces vasodilation, that is, a dilation of the blood vessels, leading to a greater influx of blood in the irradiated area. The increase in blood flow enhances oxygenation and nutrient supply at the joint level, while facilitating the elimination of metabolic waste, such as lactic acid or certain pro-inflammatory molecules. Infrared light thus helps to better regulate inflammation, which results in a reduction of pain.

Beyond its thermal effect, infrared light interacts with the mitochondria, specifically with complex IV of the respiratory chain, corresponding to cytochrome c oxidase. This interaction leads to an increase in the production of ATP, the energy necessary for the proper functioning of cells, but also to a decrease in the expression of certain pro-inflammatory cytokines, such as IL-1β, TNF-α and PGE2. These molecules are known to maintain pain and inflammation in joint tissues, particularly in cases of osteoarthritis. By limiting their production, infrared light helps to alleviate pain.

By increasing the local temperature at the joints and reducing the production of pro-inflammatory cytokines, infrared light can assist in alleviating joint pain.