Photobiomodulation (PBM) is a process by which light affects living organisms. In photobiomodulation, light is used to cause a change in living beings, both man and animal. Photobiomodulation is therefore the study of the biological effects – both beneficial and harmful – of light wavelengths on living organisms. It is also referred to as: red light therapy, mitochondrial stimulation, (mito-stim therapy), low-level light therapy, or simply light therapy.
Photobiomodulation occurs when light photons are absorbed by living tissue within a particular wavelength range on the electromagnetic light spectrum. PBM occurs from 600-1000 nanometers. These particular wavelengths of light stimulate the cellular mitochondrial light recepton enzyme, cytochrome-C oxidase. This range is known as the ‘mitochondrial stimulation band’ (or ‘healing band’) and it encompasses both red light (600-700nm) and a portion of near infrared light (700-1500nm).
Scientists have found that there exists a particular wavelength range on the electromagnetic light spectrum, known as the "mitochondrial stimulation band" or the "healing band". This wavelength band is also known as Photobiomodulation (PBM) and has shown to provide beneficial effects on living organisms. The PHM band encompasses both red light in the range of the 600-700 nanometers and a portion of the near infrared wavelength range of 700-1500nm on the electromagnetic light spectrum.
NASA research has found that the NIR electromagnetic frequency band of energy penetrates deeply into the body and can have a healing effect on our individual cells. For example, inside the mitochondria of every cell are receptors which respond to Near Infrared wavelengths. The light triggers an increase in cell metabolism, protein synthesis (including collagen), and anti-oxidant activity (meaning the cells detoxify). Additionally, it reduces inflammation and pain while simultaneously triggering growth and regeneration in the cells.
When light from within this band of wavelengths is absorbed by the cells of the human body, the cell responds by increasing ATP production, releasing Nitrous Oxide, and forming Reactive Oxygen Species – all of which work to produce large-scale systemic benefits to the health of the body. Some, but not all, of the studied benefits of PBM are: promotion of anti-aging, enhancement of athletic performance, improvements in memory and cognition, accelerated muscle healing, and boosted cellular regeneration.
The utility of PBM as a non-invasive therapy with such a wide range of benefits is truly amazing. It’s no surprise, then, that there is a new and increasingly crowded market for personal photobiomodulation devices, all making unique claims to superiority. The question at the heart of this article and Joovv’s is this: which of these various light technologies are actually effective at providing PBM to consumers?
We are beings of light and our cells need light to survive
The Importance of Incandescent
We use incandescent lamp technology. Dr. Michael Hamblin is a renowned subject matter expert in PBM and has been named in countless PBM literature, review articles, and scientific studies. He says:
“Most of the early work in this field was carried out with various kinds of lasers, and it was thought that laser light had some special characteristics not possessed by light from other light sources such as sunlight, fluorescent or incandescent lamps and now LEDs. However all the studies that have been done comparing lasers to equivalent light sources with similar wavelength and power density of their emission, have found essentially no difference between them [emphasis mine].” 
To summarize, Dr. Hamblin is saying here that there is no difference between different sources of light (LED and incandescent, for instance) in terms of ability to provide PBM. Only two characteristics of light matter: wavelength and power density. As long as the light produced is within the recommended therapeutic ranges of both these variables, the source does not matter.
So let’s examine how SaunaSpace’s incandescent lamps measure up in these two categories, wavelength and power.
WAVELENGTH: THE NEAR INFRARED HEALING BAND
Not All Wavelengths Were Created Equal.
LED lights, which are monochromatic, a word derived from Ancient Greek, meaning “one color”. In modern physics, ‘monochromatic’ refers to light of a single wavelength or frequency. In context, this means that LEDs only emit light in very narrow wavelength bands. In terms of visual light, this means that a single LED can only produce light in one specific hue of a certain color. Contrast this to SaunaSpace, where we use incandescent bulbs to deliver PBM.
What is Incandescence?
Incandescence describes the phenomenon wherein an object, when heated to high enough temperatures, produces light — think of red-hot metal, coal, or the sun. Incandescence is decidedly not monochromatic in terms of the wavelengths of light that it produces. Our incandescent bulbs produce what we call full-spectrum light, in a wavelength emission curve that spans, with our bulb’s red filter from ~600 to over 4000 nanometers. To visualize, think about the example of the sun: the sun’s light gives us every shade of every color of the rainbow. The question becomes, which breadth of wavelengths is preferable to get the full benefits of PBM?
Dr. Michael Hamblin’s research, and that of countless others, concludes that PBM is achievable across the broad 600-1000nm range. Hamblin writes:
“Many wavelengths in the red (600–700 nm) and near-infrared (NIR, 770–1200 nm) spectral regions have shown positive results… 
Dr. Hamblin’s research shows that, in fact, PBM is achievable across the full 600-1200nm range. Mitochondrial stimulation PBM has been shown to occur strongly across the 600-1000 range.
Our Bodies Have an Optical (Light) Window?
Dr. Hamblin’s seminal publication Mechanisms of Low Level Light Therapy describes our bodies as having an optical window, or a narrow band of wavelengths of light, within which tissue penetration is profound. 
We are beings of light and our cells need light to survive - lets remember that.
The Key to Photobiomodulation
Mitochondria are the power generators that exist practically within almost every cell. They contain a substance called cytochrome c oxidase (Cox), which is the primary target for Photobiomodulation. Cox is a vital component of the electron transport chain that drives cellular metabolism. As red and NIR light is absorbed, Cox is stimulated to increase adenosine triphosphate or “ATP”.
ATP is the signaling molecule that leads to
HEALING and TISSUE REPAIR.
Mechanism [See Full PMC Publication]
The current widely accepted proposal is that low level visible red to near infrared light energy is absorbed by mitochondria and converted into ATP for cellular use. In addition, the process creates mild oxidants (ROS) that leads to gene transcription and then to cellular repair and healing. The process also unclogs the chain that has been clogged by nitric oxide (NO). The nitric oxide is then released back into the system. Nitric oxide is a molecule that our body produces to help its 50 trillion cells communicate with each other by transmitting signals throughout the entire body. Additionally, nitric oxide helps to dilate the blood vessels and improve blood circulation.
 – “Biphasic Dose Response in Low Level Light Therapy”; Sulbha K. Sharma (PhD), Ying-Ying Huang (MD), James Carroll, Michael R. Hamblin (PhD)
[2, 3, 4] – “Is light-emitting diode phototherapy (LED-LLLT) really effective?”; Won-Serk Kim (PhD, MD), R Glen Calderhead (PhD)
[5, 6, 7] – “Augmentation of cognitive brain functions with transcranial infrared light”; Francisco Gonzalez-Lima (PhD), Douglas W Barrett (MD
What is Photobiology?
Photobiology is the study of the effects of non-ionizing radiation on biological systems. The biological effect varies with the wavelength region of the radiation. The radiation is absorbed by molecules in skin such as DNA, protein or certain drugs. The molecules are changed chemically into products that initiate biochemical responses in the cells.
Biological reaction to light is nothing new, there are numerous examples of light induced photochemical reactions in biological systems. We normally experience this through our eyes which are obviously photosensitive – our vision is based upon light hitting our retinas and creating a chemical reaction that allows us to see. Vitamin D synthesis in our skin is another example of a photochemical reaction. When the ultraviolet B (UVB) wavelength in sunlight strikes our skin, it converts a universally present form of cholesterol, 7-dehydrocholesterol to vitamin D3. Throughout the course of evolution, photons have played a vital role in photo-chemically energizing certain cells.
At the cellular level, visible red and near infrared light energy stimulates cells to generate more energy and undergo self-repair. Each cell has mitochondria, which perform the function of producing cellular energy called “ATP”. This production process involves the respiratory chain. A mitochondrial enzyme called cytochrome oxidase c then accepts photonic energy when functioning below par.
NO (Nitric Oxide)
ROS (Reactive Oxygen Series) → PKD (gene) → IkB (Inhibitor κB) + NF-κB (nuclear factor κB) → NF-κB (nuclear factor κB stimulates gene transcription)
ATP (Adenosine Triphosphate) → cAMP (catabolite activator protein) → Jun/Fos (oncogenic transcription factors) → AP-1 (activator protein transcription factor stimulates gene transcription)
Brain Bioenergetics [See Full PMC Publication]
Near-infrared light stimulates mitochondrial respiration in neurons by donating photons that are absorbed by cytochrome oxidase, a bioenergetics process called photoneuromodulation in nervous tissue. The absorption of luminous energy by the enzyme results in increased brain cytochrome oxidase enzymatic activity and oxygen consumption. Since the enzymatic reaction catalyzed by cytochrome oxidase is the reduction of oxygen to water, acceleration of cytochrome oxidase catalytic activity directly causes an increase in cellular oxygen consumption.  Increased oxygen consumption by nerve cells is coupled to oxidative phosphorylation, ATP production increases as a consequence of the metabolic action of near-infrared light. This type of luminous energy can enter brain mitochondria transcranially, and—independently of the electrons derived from food substrates—it can directly photostimulate cytochrome oxidase activity.