From: hubermanlab
Understanding the effects of light on human biology reveals a fascinating interplay between environmental cues and our physiological processes. Different wavelengths of light have distinct impacts on various health aspects, from skin health to mood regulation, by acting on specific biological pathways. In the Huberman Lab Podcast hosted by Andrew Huberman, a professor of neurobiology and ophthalmology at Stanford School of Medicine, these effects are explored in detail.
Light as Electromagnetic Energy
Light is essentially electromagnetic energy that travels in waves, impacting biological tissues at numerous depths and inducing varied responses. These waves exist in a spectrum of wavelengths, each corresponding to different colors and energies. This spectrum includes visible light that humans can see and invisible segments in the infrared and ultraviolet ranges that still influence our biology extensively [00:10:00].
Physics of Light
- Light exists as electromagnetic energy.
- Different wavelengths correspond to different colors.
- Wavelengths impact tissues at varying depths [00:16:02].
Biological Impact of Wavelengths
The biological impact of different wavelengths revolves around the direct and indirect effects they impose on cells and tissues. The direct effects involve light acting on cells with photoreceptors, such as rods and cones in our eyes that discern light of various wavelengths, modulating vision and mood [00:24:03]. Indirect effects involve broader pathways where light impacts hormone production or immune responses, as mediated by organs such as the brain and spleen, often triggered by the action of the central nervous system [01:21:00].
Examples of Wavelength Specific Effects
Red Light and Near-Infrared Light
- Visual and Neuronal Health: Red light and near-infrared light have shown promise in reversing age-related vision decline by boosting mitochondrial function, reducing reactive oxygen species, and thereby enhancing ATP production in retinal cells [01:53:01].
- Skin and Wound Healing: These wavelengths penetrate deep skin tissues, promoting healing and even aiding in the treatment of conditions like acne by stimulating cellular repair mechanisms [01:40:06].
Ultraviolet (UV) Light
- Mood and Seasonal Depression: UV light, especially UVB, plays a vital role in hormone regulation and has been shown to improve mood and energy by increasing hormone levels such as testosterone and estrogen when exposure is sufficient [00:56:02].
- Pain Reduction and Immune Function: UVB exposure increases endogenous opioids, reducing pain pathways, and also influences immune function through the activation of sympathetic nervous system pathways [01:07:04].
Red Light and Infrared Light Protocol
- For vision and neuronal health: Use red light early in the morning for 2-3 minutes at a safe distance to avoid retinal damage [02:00:02].
Considerations and Best Practices
While there are measurable benefits to light exposure, the context and intensity matter significantly. Reducing harmful blue-light exposure at night and ensuring adequate protective measures like sunscreen for UV exposure are essential. Especially in shift workers, using red light as an artificial source can help maintain alertness without significantly disrupting circadian rhythms [02:07:36].
The interplay of light wavelengths and our health is a burgeoning field of study that underscores the versatility of phototherapy. As research progresses, understanding and harnessing these effects could lead to groundbreaking applications in both preventive and therapeutic contexts.