Barry Pearson wrote:Thought: When humans and pre-humans were evolving, there was a lot of red light in the mornings and evenings.
Where does this come from!?
Note that I mentioned this in the context of using Red Light Therapy. I wasn't saying anything we don't already know.
Before we had artificial lighting, we were constrained by sunlight. In Africa, being nearer the equator than most places today, there is more consistency of lengths of daylight. So our distant ancestors evolved with redish light early and late, (sunrises and sunsets are redish), and white light in the middle of the day. I assume our bodies (including brains) are compatible with that.
Now that many of us live far from the equator, and we use a lot of artificial light, it is far less likely that we are running our bodies (including brains) in a way that is compatible with our evolved state. Our times are different and vary, and we get a lot of bluish light because of modern lamps and screens, etc. This can interfere with sleep, and probably various other aspects of our circadian rhythms.
I try to compensate for this: my bedroom windows are blacked out and there are no other distracting lights in my bedroom, so my sleep patterns are not dictated by artificial lighting or the spectra of modern screens and lamps. I use f.lux on my PC, and mild-blue-blocking clip-ons while watching TV. My light bulbs have a colour temperature of 2700 Kelvin, a bit "warmer" than typical bulbs.
I use Red Light Therapy in a way that I think is more consistent with the light experiences of our distant ancestors: I use it at about the same times each day, morning and evening. Not at times dictated by what the sun is doing outside.
I believe therefore that it is certainly safe, and very likely beneficial, in a number of ways.
The science isn't as solid as we would like, but it shows some promise. For example:
"Turning On Lights to Stop Neurodegeneration: The Potential of Near Infrared Light Therapy in Alzheimer's and Parkinson's Disease"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4707222/
"Photobiomodulation for Alzheimer’s Disease: Has the Light Dawned?"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6664299/
"Alzheimer's: How light therapy could protect the brain"https://www.medicalnewstoday.com/articles/325118.php#1
At 72 I can't wait for all the science to come in! I've placed my bets on the assumption that at least I'm not doing any harm.
I have a genetic extra risk of Macular Degeneration, and I have traces of drusen in my eyes. They appear to have stabilised, but there are suggestions that Red Light Light Therapy can help with eye-health too.
(I also have a genetic extra risk of Celiac Disease. I'm not genetically blessed! I've avoided gluten for years).