"Light is a mode of communication." Light therapy is a well-researched modality that deserves our full attention, but most lack the foundational knowledge needed to be motivated & confident to share.
In this lesson, we introduce the foundational science related to light and the electromagnetic (EM) spectrum, including bioactive light and how it affects the body.
“Light is a mode of communication”
We need to dispense with the industrial idea that light’s only purpose is to illuminate. This fallacy is perfectly captured in the market push towards LED white light of everything, and disparagement of older technology such as incandescent bulbs… Framing LED bulbs as being more “efficient” assumes that light’s only purpose is to illuminate, thus justifying the industrial refinement of light into something that uses the minimum energy necessary to illuminate an area. This framing is not only false, but unhealthy. Light is a mode of communication, and like all modes of communication can be used to convey actions and effects. For instance, at a clinic or hospital you may have had a pulse oximeter placed on your finger. This device utilizes light to determine how much oxygen is circulating in your blood… At the most basic level, our tissue is full of proteins which communicate wavelengths of light – these are called chromophores. Use of light to communicate with and effect biologic change is the whole basis of a relatively new field of study called optogenetics, pioneered by Karl Deisseroth. In this field, scientists attach light-sensitive proteins (ie chromophores) to pathways they want to effect, and can thus control the biology and behavior of experimental animals with pulses of lights.
Contents
New Lesson: Light & The Electromagnetic Spectrum
Vocabulary
The Electromagnetic (EM) Spectrum
EM Radiation, EM Energy, Photons
Visible Light, Color
Bioactive Light
Continue
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New Lesson: Light & The Electromagnetic Spectrum
Objective
Be familiar with the foundational science that underpins light therapy and other applications that derive from an understanding of the electromagnetic (EM) spectrum and light, plus the clinically researched effects of bioactive light on the body.
Vocabulary
bioactive light, blue light, color spectrum, electric charge, electric field (E), electromagnetic (EM) energy, electromagnetic fields (EMFs), electromagnetic radiation (EMR), electromagnetic (EM) spectrum, electromagnetic (EM) waves, electromagnetism, EM (in physics), energy transfer, far-infrared light, gamma rays, infrared light, light, light therapy, low-level laser light therapy (LLLT), magnetic field (B), magnetic force, microwaves, near-infrared light (NIR), photomodulation / photobiomodulation (PBM), photon, phototherapy, radiant energy, radio waves, red light, red light therapy, ultraviolet (UV) light, visible light, wave-particle duality, X-rays
Following is an excerpt from the lesson.
Vocabulary
Having an excellent vocab list for the subject at hand greatly increases our ability to understand, retain, and apply knowledge from multiple sources.
BIOACTIVE LIGHT – Electromagnetic (EM) wavelengths that affect the body’s biological processes; five forms are blue light, UV light, far-infrared light, red light, and near-infrared light (NIR) [source and source]
BLUE LIGHT – A form of bioactive light; regulates our brain’s circadian rhythm, the internal process that governs the sleep-wake cycle, “which in turn regulates numerous neurotransmitters and hormones” [source and source]
CHROMOPHORE – “A section of a larger compound that absorbs and reflects specific electromagnetic radiation [which is] observed as color” [source]
COLOR SPECTRUM – The part of the electromagnetic (EM) spectrum visible to the human eye; violet has the shortest wavelength (around 380 nm) and highest frequency; red has the longest wavelength (around 700 nm) and lowest frequency
ELECTRIC CHARGE – A property of matter that governs how particles are affected by an electric or magnetic field; can be positive or negative [source]
ELECTRIC FIELD (E) – Produced in the surrounding space by each charged object; “a second charge ‘feels’ the presence of this field” [Britannica]
ELECTROMAGNETIC (EM) ENERGY – The energy carried by electromagnetic (EM) radiation; combines electric and magnetic forces [source]; travels in waves [NASA]; a unit is called a photon; the force behind radio, television, and x-ray machines
ELECTROMAGNETIC FIELDS (EMFs) – Caused by “the mutual interaction of electric and magnetic fields” [source]; “produced by all forms of electrical or electronic equipment, whether it’s a radio, TV, computer, cell phone, dimmer switch – or an electrically-powered frequency medicine device”[source]; in physics, the abbreviation is EM fields while EMF in that context refers to electromotive force
continue…
The Electromagnetic (EM) Spectrum
Image source: NASA
Key Points
Our world is comprised of patterns of energy in perpetual motion — called vibration.
In physics, vibration is measured by the number of waves (the way that energy moves) that pass a fixed point in time. The name given to this way of measuring vibration is frequency and it’s commonly expressed in hertz (Hz).
Vibrational frequencies are presented on a scale, called the electromagnetic spectrum.
The vibrating waves produce light, only a tiny fraction of which is perceived by the human eye.
When the distance between wavelengths is longer, the energy is said to be slower.
When the distance between wavelengths is shorter, the energy is said to be faster.
Vibrations of different frequencies are given different names such as radio waves, microwaves, infrared light, the color spectrum, ultraviolet light, X-rays and gamma rays.
EM Radiation, EM Energy, Photons
Key Facts
Electromagnetic radiation (EMR) refers to the flow of energy from electric and magnetic fields that form electromagnetic (EM) waves such as radio waves, visible light, and gamma rays. [Britannica]
EMR travels at the speed of light (186,000 miles per second or 300,000 kilometers per second)” [source]
For example, satellite dishes that create television or computer images are receiving EMR — electromagnetic (EM) waves of that travel at the speed of light.
The word “light” may refer to the entire EM spectrum. Alternatively, when the word “light” is referring only to visible light, it is a subset of the EM spectrum.
EMR carries energy. Called electromagnetic (EM) energy, it travels in waves. [NASA]
Visible light and all EMR exhibit wave-particle duality. [U.S. Dept. of Energy]
The smallest possible unit of light and all EM energy is called a photon. [U.S. Dept. of Energy]
Einstein suggested in 1905 that light is both particles and waves. “The energy in the photons determines the type of electromagnetic radiation the photons transmit.”
Photons are the smallest possible particles of electromagnetic energy and therefore also the smallest possible particles of light. Photons can travel at the speed of light because they have no mass (thanks to relativity). Photons also have no charge. Photons represent the entire spectrum of electromagnetic radiation. This includes radio waves, gamma-rays, and visible light. Like many other particles governed by quantum mechanics, photons have the characteristics of both waves and particles. Photons travel in a wave-like fashion, in which the local electric and magnetic field oscillates in intensity, regularly swinging back and forth between high and low energy levels. The energy in the photons determines the type of electromagnetic radiation the photons transmit. This means low-energy photons carry radio waves [and]… high-energy photons carry gamma waves… Scientists’ discovery that photons are both waves and particles was a key part of the development of quantum mechanics... Einstein suggest[ed] in 1905 that light is both particles and waves. His explanation is based on the photoelectric effect. This is the way a sheet of metal emits electrons when hit with light. Einstein demonstrated that the intensity of the light shined on the metal is tied to the number of photons in the light. The frequency (or color) of the light is tied to the amount of energy each photon carries. – U.S. Department of Energy, DOE Explains Photons link
Visible Light, Color
Image source: ThoughtCo
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Key Points
Visible light refers to the wavelength frequencies that humans can see. It ranges from approximately 380 to 750 nanometers and 400 to 790 terahertz on the electromagnetic spectrum. [source]
Within visible light, violet has the shortest wavelength (around 380 nm) with the highest frequency.
Red has the longest wavelength (around 700 nm) with the lowest frequency.
Some animals can see colors outside the range that is visible to humans, such as ultraviolet or infrared light. “Bees and other insects can see ultraviolet light, which is commonly reflected by flowers. Birds can see into the ultraviolet range (300–400 nm) and have plumage visible in UV.” [source]
Bioactive Light
Light is “bioactive” which means that it affects our body. [dictionary]
“Bioactive light” refers to EM wavelengths that affect the body’s biological processes. [source and source]
Different forms of light affect the body in different ways. These five forms of bioactive light are reported to have the following effects.
Blue Light
Regulates our brain’s circadian rhythm, the internal process that governs the sleep-wake cycle, “which in turn regulates numerous neurotransmitters and hormones” [source and source]
“Excessive exposure from screens, fluorescent lights, and other artificial sources can disrupt this rhythm, leading to fatigue and poor sleep quality” [source and source]
UV Light
Enables the synthesis of Vitamin D from the sun; “unlike most nutrients, the hormonal nature of vitamin D means it has a broader systemic impact, influencing not just bone health but also immune function, cell growth, and inflammation control” [source and source and source]
continue…
Light Therapy
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