The science of arousal
The effects of light energy on tissue are numerous. These effects may include improved blood flow, improved blood vessel health, the formation of new blood vessels, and thickening of older tissues by formation of new collagen, reduction in pathogenic bacteria, and even reduction in fungus such as yeast. Below is a depiction and description of mechanisms of action.
Near Infrared light and red light can safely penetrate skin to reach deeper structures such as blood vessels and connective tissues. The walls of blood vessels are composed of numerous cells. Tiny little factories known as mitochondria power all cell types. Infrared light and red light stimulate these energy factories and surrounding enzymes to release Nitric Oxide and ATP. ATP is the fuel that drives the cell. Nitric Oxide has a powerful immediate relaxing effect on smooth muscle of blood vessel walls resulting in vasodilatation. Indeed, patients in emergency rooms having heart attacks are given “nitro” to immediately relax the blood vessels of the heart to allow more blood flow. Organic nitrates, such as “nitro” and Nitric Oxide are great dilators of blood vessels and rapidly improve blood flow. Nitric Oxide is also referred to as endothelial-derived relaxing factor.
Vessel Health: There is also an inverse relationship between NO pathways and atherosclerosis. Patients with impaired NO pathways seem to have higher amounts of blood vessel plaques (narrowed blood vessels with poor blood flow and oxygen delivery to tissues). Over time, improve NO pathways may decrease atherosclerosis and create healthier “younger” blood vessels.
Reduction of Bacteria: Blue light energy has a bactericidal effect and has been shown to kill pathogenic bacteria. Although ultraviolet light is also lethal to many pathogenic bacteria, as we know, UV light is very detrimental to the skin. Blue light is much safer. Over time, blue light leads to a reduction in pathogenic bacteria on skin and mucous membrane surfaces.
Reduction in Yeast: Near IR light energy damages the genetic material inside of fungus (DNA). DNA damage leads to impaired fungal growth. Over time the yeast population on skin and mucous membranes decreases (The use of IR energy to treat toe nail fungus is now in common practice).
Improved Collagen: Light energy causes denaturing and “shrinking” of old collagen and also stimulates fibroblasts to lay down new collagen. Recall that red and IR light energy stimulates the energy factories of cells (this process is also referred to stimulation of cellular respiration). Fibroblasts are the cells that rebuild tissue. They lay down new collagen and repair damage. Fibroblasts absorb red and IR light energy quite well. The final result is a thickening of tissue to a more youthful state.
NO is an important cellular signaling molecule involved in many physiological and pathological processes. It is a powerful vasodilator with a short half-life of a few seconds in the blood. Long-known pharmaceuticals like nitroglycerine and amyl nitrite were discovered, more than a century after their first use in medicine, to be active through the mechanism of being precursors to nitric oxide.
Nitric oxide, known as the ‘endothelium-derived relaxing factor’, or ‘EDRF’, is biosynthesized endogenously from L-arginine, oxygen and NADPH by various nitric oxide synthase (NOS) enzymes. The endothelium (inner lining) of blood vessels uses nitric oxide to signal the surrounding smooth muscle to relax, thus resulting in vasodilatation and increasing blood flow.
Nitric oxide (NO) contributes to vessel homeostasis by inhibiting vascular smooth muscle contraction and growth, platelet aggregation, and leukocyte adhesion to the endothelium. Humans with atherosclerosis, diabetes, or hypertension often show impaired NO pathways.[
Nitric oxide secreted as an immune response is as free radicals and is toxic to bacteria; the mechanism for this includes DNA damage
It was found that NO acts through the stimulation of the soluble guanylate cyclase, which is a heterodimeric enzyme with subsequent formation of cyclic GMP. Cyclic GMP activates protein kinase G, which causes reuptake of Ca2+ and the opening of calcium-activated potassium channels. The fall in concentration of Ca2+ ensures that the myosin light chain kinase (MLCK) can no longer phosphorylate the myosin molecule and thereby stopping the crossbridge cycle leading to relaxation of the smooth muscle cell
Antibacterial Effect of Blue Light. This inactivation mechanism, known to be oxygen dependent, is thought to be a result of the photoexcitation of naturally occurring endogenous porphyrins, which act as endogenous photosensitizers within the bacterial cells. This porphyrin excitation leads to energy transfer and, ultimately, the production of highly cytotoxic, oxygen-derived species, most notably, singlet oxygen. In general gram-positive bacteria require a much lower dose of 405-nm light for inactivation than do gram-negative bacteria