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Huberman Lab
Using Light (Sunlight, Blue Light & Red Light) to Optimize Health
Apr 18, 2022
02:19:33
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Quick takeaways
- Light exposure can optimize sleep, hormone levels, mood, and overall mental and physical health.
- Different wavelengths of light penetrate tissues to different depths, making it a unique tool for modulating biology.
- Light is converted into signals in our body through the absorption of light energy, impacting cell function and hormone production.
- Optimizing light exposure, including sunlight and specific wavelengths, can have significant benefits for our health.
- Red light therapy shows promise for improving skin health, wound healing, vision, and brain function, including cognitive decline.
Deep dives
Light as a Powerful Modulator of Biology
Light has powerful effects on various aspects of our biology, including skin health, wound healing, hormone balance, sleep regulation, mood, and even dementia. It can be translated into electrical and hormone signals in our brain and body, leading to changes in cell function. Phototherapy has a solid scientific foundation, with over a hundred years of research supporting its efficacy. Recent studies have shown that red light therapy can offset age-related vision loss, and specific wavelengths of light can modulate different aspects of our health.
Understanding the Physics of Light
Light is electromagnetic energy that can be categorized into different wavelengths, including those visible to the human eye and those that are not. Different wavelengths of light penetrate tissues to different depths. Long wavelength light, such as red and near infrared light, can penetrate deeper into the skin and impact cells and organs. This ability to target specific locations and organels within our cells makes light a unique modulating tool for our biology.
The Biology of Light and its Conversion into Signals
Light is converted into signals in our body through the absorption of light energy by pigments or properties of specific tissues. For example, photo receptors in the back of our eyes absorb light energy to create visual images and regulate functions like sleep and wakefulness. Melanocytes in the skin absorb UV light, leading to changes in pigmentation. Different wavelengths of light can also directly impact cells and organs, modulating their function and even promoting mating behavior through the activation of hormone production.
Practical Applications and Considerations
Optimizing light exposure can have significant benefits for our health. Getting appropriate sunlight exposure, especially during the longer days of summer, helps regulate our circannual rhythms and melatonin production. However, it is important to be cautious about excessive light exposure at night, as it can disrupt sleep and melatonin levels. When seeking the benefits of light therapy, using specific wavelengths, such as red or near infrared light, and ensuring proper dosing and timing can optimize outcomes. However, careful consideration should be given when using melatonin supplementation due to its complex modulation of various biological functions.
Sunlight exposure and its effects on testosterone
Sunlight exposure, particularly to UVB light, has been shown to increase testosterone levels. People with lighter skin and/or lower UVB light exposure tend to have greater increases in testosterone. Daily sun exposure for 20-30 minutes has been shown to boost testosterone levels in both men and women, with greater effects observed in individuals with paler skin.
Seasonal changes in testosterone levels
Testosterone levels naturally fluctuate throughout the year, with lower levels in winter months and higher levels in spring and summer months. Longer days and increased sunlight exposure are associated with higher testosterone levels. These seasonal variations in testosterone have important implications for reproductive and sexual behaviors.
Sunlight exposure and its effects on mood and desire to mate
Sunlight exposure, particularly in the morning, has been shown to improve mood and increase romantic passion. Both males and females experience an increase in sexual passion and desire to mate after exposure to UV light. Sunlight exposure triggers hormonal pathways, such as increased testosterone and estrogen, which can influence psychological changes related to desire and mood.
Red light therapy and its benefits for skin and neuronal function
Red light therapy, specifically the use of low-level light treatment with red and near-infrared wavelengths, has been shown to have positive effects on dermal conditions, including acne, wound healing, and scar reduction. It can activate mitochondria and increase ATP production, while reducing reactive oxygen species. Red light therapy has also been found to improve visual function in individuals aged 40 and older, leading to enhanced visual acuity.
Improving Visual Acuity with Red Light Therapy
Research on the triton exam, a visual testing method, revealed a 22% improvement in visual acuity by targeting short wave-length cones. This improvement is significant compared to the usual 5% to 10% improvements seen in vision studies. Additionally, red light therapy was found to reduce reactive oxygen species in cones, which are highly metabolically active cells in the body, and improve the function of short wave-length and medium wave-length cones. This therapy shows promise for reversing age-related vision loss.
The Impact of Red Light Therapy on Brain Neurons
Light stimulation has been shown to induce gamma oscillations in brain neurons, which have restorative effects on learning, memory, and cognitive decline. By delivering specific patterns of light flicker, not only in visual areas but also in other brain regions, gamma oscillations can be triggered. These oscillations reduce amyloid plaques and tau proteins associated with Alzheimer's and age-related cognitive decline, while enhancing synaptic maintenance and other neuroprotective pathways. This non-invasive phototherapy offers potential for improving brain function and offsetting neurodegenerative conditions.
18.
Skin Exposure to U v B Light Induces a Skin Brain Gonad Axis and Sexual Behavior
3min
25.
A Visual Circuit Related to the Pery Equeductal Gray for the Anti Noseceptive Effects of Bright Light Treatment
2min
29.
U v B Exposure to Your Eyes Can Be Beneficial for Eye Health and Immune Function
2min
I describe the mechanisms by which different wavelengths of light impact the cells, tissues and organs of the human body, and how specifically timed light exposure of specific wavelengths can be used to improve sleep, enhance alertness, modulate hormone levels, and improve mood. I also explain the use of ultraviolet and infrared phototherapies to relieve pain increase testosterone and estrogen levels; improve skin health, appearance and wound healing; and how red light can be used to offset age-related vision loss and provide neuroprotection. Throughout the episode, I describe the mechanisms of light-based therapies and actionable tools that people can use positively impact mental and physical health.
For the full show notes, visit hubermanlab.com.
Thank you to our sponsors
AG1: https://athleticgreens.com/huberman
LMNT: https://drinklmnt.com/hubermanlab
Waking Up: https://wakingup.com/huberman
Momentous: https://livemomentous.com/huberman
Timestamps
(00:00:00) Using Light to Improve Health
(00:04:49) Sponsors: AG1, LMNT
(00:09:56) Physics of Light, Electromagnetic Energy
(00:12:23) Wavelengths of Light
(00:15:38) How Light Penetrates Tissues
(00:20:13) Light & the Body: Direct & Indirect Signals
(00:28:35) Light, Seasonality & Melatonin
(00:33:40) Melatonin: Regulatory & Protective Effects
(00:38:49) Tools: Optimizing Melatonin Levels
(00:44:49) Sun (UVB light) Exposure, Mating Behavior, Testosterone & Estrogen
(00:58:09) Seasonality, Romantic Passion & Testosterone
(01:02:13) Tool: Skin Sun Exposure & Testosterone
(01:06:13) Light & Improved Pain Tolerance
(01:11:55) Protocol: Sun Exposure & Chronic Pain
(01:12:48) Tools: Sunlight (UVB), Blue-Light Blockers, Seasonal Affective Disorder (SAD)
(01:19:44) Light & Enhanced Immune Function
(01:23:30) Tool: Light During Winter Months
(01:26:18) Light Therapies: Local vs. Systemic Exposure
(01:28:54) Tool: Improving Mood, Timing of Natural & Artificial Light
(01:32:44) Light Conditions & Sleep Optimization
(01:39:00) Infrared Light, Skin & Wound Healing
(01:46:00) Infrared Light Therapy & Skin, Low-Level Laser (Light) Therapy (LLLT)
(01:49:20) Infrared Light & Age-Related Vision Loss
(01:59:36) Tools: Infrared Panels, Morning Exposure
(02:05:22) Infrared Light at Night, Shift Work
(02:08:35) Light Flicker Phototherapy & Neuroprotection
(02:19:07) Phototherapies for Health
(02:20:50) Zero-Cost Support, YouTube Feedback, Spotify Reviews, Apple Reviews, Sponsors, Supplements, Instagram, Twitter, Neural Network Newsletter
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