Light therapy is among the earliest recorded healing modalities. Solar therapy was first used by Egyptians and forms of light therapy were also practiced by the ancient Greeks, Chinese and Indians.
There’s no question that light exerts biological effects: in fact, the body needs light to be healthy. Clinical studies are now establishing how different wavelengths of light affect the body at a cellular level, the conditions that can be successfully treated using light therapy, and the optimal conditions needed to absorb the benefits of light-based treatments.
Understanding red light wavelengths
All light falls along a spectrum of wavelengths. Red and infrared light that falls within the wavelength range of 650-850 nm is extremely beneficial, and often referred to as the “therapeutic window”. These wavelengths of light are bioactive in humans and affect the function of our cells.
Red light emits wavelengths of between 620-700 nm. All red light wavelengths are effective and offer health benefits, although certain wavelengths are more powerful than others–particularly those that fall between 630-680nm. Visible red light within this range can penetrate deep into the skin, offering rejuvenating and balancing outcomes for a range of health conditions.
Red and near-infrared light are part of the electromagnetic spectrum, and more specifically, part of the spectrum of light emitted by the sun. These wavelengths of light are “bioactive” in humans.
Below is a chart outlining the electromagnetic spectrum:
Electromagnetic waves range from 0.0001 nanometers (gamma waves) all the way to over meters (radio waves).
If you remember high school physics, when you pass white light through a prism it separates out the different colors based on their wavelengths (ROYGBIV). Only a tiny part of this spectrum (roughly400nmto 700nm) is actually visible to the human eye.
At the highest end of the visible light spectrum is red light, which goes from a little over 600nm to approximately 700nm. Above the visible light spectrum is near infrared (NIR) from about 700nm to a little over 1,100nm.
It is specifically these red and near-infrared wavelengths that have amazing effects on our bodies. Most research showing benefits of red light and near-infrared light have used wavelengths in the ranges of 630-680nm and 800-880nm.
It’s all about the depth of light penetration
Most wavelengths of light (UV, blue, green, yellow, etc.) are unable to penetrate into the body – instead they stay in the layers of the skin.
However, as the picture below shows, red and near-infrared light is able to penetrate deeper into the human body and are able to reach the cells, tissues, blood, nerves, into the bones and even into the brain.
The benefits of red light: Red light between 600-700nm offer benefits for skin texture and tone, smoothing fine lines and wrinkles, promoting collagen production and generally rejuvenating the appearance of skin and hair.
The benefits of near-infrared light: Near-infrared light (NIR) 700nm – 1100nm. penetrates deeper into the tissues to assist with wound healing, muscle recovery, nerve injury and joint pain.