Using Light for Health

The light spectrum explained: UV, visible, red, and near-infrared all affect biology

UV light can both damage and benefit the body. Red and near-infrared light have powerful effects on mitochondria and cell health.

"And you're welcome to think of the different wavelengths of light as different colors, but do understand that there are truly colors of light that you and I can't see, and yet that have powerful impact on your brain and body."

The light spectrum explained: UV, visible, red, and near-infrared all affect biology

UV light can both damage and benefit the body. Red and near-infrared light have powerful effects on mitochondria and cell health.

"And you're welcome to think of the different wavelengths of light as different colors, but do understand that there are truly colors of light that you and I can't see, and yet that have powerful impact on your brain and body."

UVB light to skin boosts testosterone and estrogen via a pathway parallel to melatonin

Beyond the melatonin suppression pathway, a second parallel pathway uses UVB light on skin to directly increase gonadal hormone output, boosting.

"Okay, so if melatonin is suppressive to the so-called gonadal axis and reduces overall levels of testosterone and estrogen in males and females, and light inhibits melatonin, then when there's more light, then there's less melatonin and more hormone output from the gonads. And indeed, that's how the system works."

UVB sunlight on skin increased testosterone, estrogen, and sexual desire in humans

A study found UVB exposure increased gonadal weight in mice and boosted passion, aggressiveness, and sexual desire in humans.

"In this study, they were able to very clearly establish that it is sunlight exposure to our skin that is causing these hormone increases that they observed in mice and humans."

UVB light through the eyes activates pain-relieving pathways in the brain

Both skin and eye exposure to UVB light trigger anti-pain pathways.

"It's fine to wear eyeglasses or contact lenses. In fact, they will just serve to focus that light on to the very cells that you want those light beams to be delivered to."

UVB light via eyes and skin both reduce pain through parallel biological pathways

Recent research shows light arriving at the eyes, specifically UVB, triggers pain-relieving pathways alongside the known skin-mediated pathway.

"This very recent study indicates that it's also light arriving at the eyes. And in this case, again, UVB light, ultraviolet blue light of the sort that comes from sunlight that is triggering these anti-pain or pain relieving pathways."

UVB exposure through the eyes speeds up hair growth via melanopsin cells

Hair grows faster in longer days, triggered by UVB exposure to both skin and eyes.

"They've live in little so-called niches in our skin with these hair stem cells, and your hair grows faster in longer days. That too is triggered by UVB exposure, not just to the skin, but to the eyes."

Even dim light during sleep disrupts metabolism and raises morning blood glucose

Light exposure during sleep disrupts the sympathetic nervous system and metabolism. Even dim light at night alters morning blood glucose levels.

"What this study shows is that light exposure, even in sleep is disrupting our autonomic, in this case, the sympathetic arm of the autonomic nervous system in ways that are disrupting metabolism, probably in sleep, but certainly outside of sleep."

Low-level light therapy treats acne, improves wound healing, and reduces TBI symptoms

Infrared and near-infrared low-level light therapy has been shown effective for acne, skin lesions, wound healing, and even traumatic brain injury.

"Low-level light therapies have been shown to be effective for a huge number of biological phenomenon and medical treatments."

Red and near-infrared light improve vision and brain cell function

Red and near-infrared light can enhance retinal cell function to improve vision and brain cell performance.

"And in recent years, there've been some just beautiful examples that exist not only in the realm of skin biology, but in the realm of neurobiology, whereby red light and near-infrared light can actually be used to enhance the function of the cells that for instance, allow us to see better and indeed cells that allow us to think better."

Protocol: 2-5 min of red light viewing in the morning improves declining vision

Red light reduced reactive oxygen species in rods and cones, rescuing short and medium wavelength cone function.

"Red light of the sort used in these studies was able to reduce the amount of reactive oxygen species in the rods and cones and to rescue the function of this particular cone type, the short wavelength and medium wavelength cones, which if you think about the study is a little bit surprising because it was red light and near infrared light, not short wavelength light that was used in order to create this improvement in cellar function."

Red light rescued rod and cone function by reducing reactive oxygen species

Red and near-infrared light reduced reactive oxygen species in photoreceptor cells, rescuing function in short and medium wavelength cones.

"Red light of the sort used in these studies was able to reduce the amount of reactive oxygen species in the rods and cones and to rescue the function of this particular cone type, the short wavelength and medium wavelength cones, which if you think about the study is a little bit surprising because it was red light and near infrared light, not short wavelength light that was used in order to create this improvement in cellar function."

Red light for ovarian and testicular health: promising but still preliminary

Red light therapy for gonadal health and testosterone is promising, but rodent data don't translate easily to humans yet.

"I know there's a lot of interest nowadays, for instance, in the use of red light and other wavelength light therapies for ovarian health and testicular health."