Properties of Sunlight That Impact Health
This image shows all the known wavelengths in the Spectrum (EMS).
Colored light is the only kind of wavelength humans can see. Ultra-violet (UV) and Infra-red (IR) wavelengths are invisible and essential.
The tiny amount of UV light in Earth’s sunlight sets up many vital light-driven biological processes in man.
Image 1: The relative size of wavelengths in the EMS
Image 2: Illustration of vitamin D pathways
Beneficial effects of sunlight:
UV light on the skin transforms cholesterol into cholecalciferol. This lowers cholesterol, a beneficial heart effect [1].
UV light on the skin also releases nitric oxide (NO) which opens blood vessels. This lowers blood pressure, another beneficial heart effect [2].
And from the 1998 Nobel Prize winner, “The brain has more Nitric Oxide than any other body tissue.” [3]
... More Beneficial Effects of Sunlight
Light intensity makes a difference – indoor light is only 500 Lux but at least 10,000 Lux is needed to stimulate the brain. Overuse of light at night affects circadian rhythms. This diagram shows how light intensity has changed since light bulbs.
Image 3: Changes inlight intensity over the course of human evolution
Sunlight through the eyes stimulates the pineal gland in the brain which regulates body rhythms for better sleep [4].
Sunlight through the eyes releases beta endorphins (mood boosters) in the brain [4].
Image 4: How Sunlight affects the brain
References: 1. Holick MF, et al, https://doi.org/10.1210/jc.2011-0385. 2.https://www.ted.com/talks/richard_weller_could_the_sun_be_good_for_your_heart?language=en 3. Dr. Louis Ignarro, Nobel Prize in Medicine, 1998. 4. Liberman, J. (1991) Light Medicine of the Future, Bear & Company, One Park Street, Rochester, VT, 05767. Images: 1. http://www.bio.miami.edu/dana/dox/photosynthesis.html. 2.Skin graphic from: Holick MF, [Ref #1]. 3.https://www.researchgate.net/figure/Typical-illuminance-for-light-sources-7_fig2_325960961.
