Red light therapy has evolved into a fast-growing industry ever since a large number of studies on deep red and infrared light (IR) revealed a surprising link between near-infrared (NIR) energy and health. There also appears to be evidence confirming that deep red and NIR light can improve the quality of our sleep. Warm color full spectrum IR-enhanced light bulbs are a good indoor source of deep red and NIR light.
IR light is naturally produced by our sun ☀️ and can penetrate deep into our body, and that produces the warm feeling we get outdoors in the sunshine. The full spectrum of the Sun may appear white to our eyes but it is a also a rich source of red light therapy for our bodies. Studies have also shown that the same deep red and NIR light is also crucial for our cells’ ability to produce melatonin. The more melatonin our cells can produce, the more effective they become at repairing themselves in the process of protecting the body from illnesses and diseases.
Below is a comparison between how visible & near-infrared (Vis/NIR) light from direct sunlight is reflected from a hand versus a green leaf. Despite being only 145 microns thick, the leaf reflects nearly twice as much NIR between 750-850nm. That same spectral range coincides with the human tissue transparency window, which has a maximum penetration depth between 800-850nm.
When we look at the leaf, our eyes only see the Vis green color (reflected green-yellow light) represented by the small peak around 540nm. Our visual system with a peak photopic sensitivity at 555nm is completely unaware that a significant portion of invisible solar NIR energy is also being reflected by that same leaf and absorbed into our body.
Under direct sunlight, the infrared content of daylight is around 55%. A major part of the NIR energy gets absorbed by our body and used in various cellular functions. NIR light energy can penetrate several inches deep into our body and is used to energize the mitochondria in the subcutaneous tissue, muscles, and various organs.