Light exposure during sleep impairs cardiometabolic function

Research on Blue light and sleep: https://justgetflux.com/research.html

https://en.wikipedia.org/wiki/Melanopsin :

> Melanopsin photoreceptors are sensitive to a range of wavelengths and reach peak light absorption at blue light wavelengths around 480 nanometers.[30] Other wavelengths of light activate the melanopsin signaling system with decreasing efficiency as they move away from the optimum 480 nm. For example, shorter wavelengths around 445 nm (closer to violet in the visible spectrum) are half as effective for melanopsin photoreceptor stimulation as light at 480 nm.[30]

Under Melanopsin > infobox > "Biological process", e.g. "entrainment of circadian clock by photoperiod" and "regulation of circadian rhythm" are listed.

I use this: https://www.amazon.com/dp/B07KC5DWCC

I cut off the sleeve of an old fleece pullover. Works great as night cap and eye cover.

(I previously used a sleep mask bought on Amazon but found it slipped off too often. Also, the straps irritated my ears.)

The research discusses 100 lux for one whole night, which is quite a lot (indoor levels range from 100 to 1000 lux, outdoors from 10k on a cloudy day to 120k with direct sunlight at noon.) Like others here, I’m curious about other strengths of light - I assume up to 0.1 lux is fine, as moonlight is typically 0.05-0.1 lux, but what about between 0.1 and 100 lux? And what about light exposure during part of the sleep cycle? There’s quite a lot of sleep research, much of it poor quality, so I’d be grateful for any specific study suggestions.

> I don't use a set of blackout curtains, but I know several friends that say it makes a real difference.

Maybe a year ago, I was planning on having a sleep study done. At some point in my 30s I stopped feeling like I was recovering when I slept. I decided, however, that there were some things that I could work on improving before having a sleep study.

Most of what I addressed falls under sleep hygiene: Blackout curtains, better sheets, better blanket/comforter, better pillows, a better mattress, a sleep mask, reducing noise. It took a while to sort all of this out. "Better" is also subjective.

I also slowly worked on getting to bed earlier. I used to get into bed around 11:30pm. Now I'm in bed between 9:30 and 10pm. I read a little bit and then sleep. I stopped having calories after ~7pm.

We have young children, too. 3 under 3. I sleep very well now. Despite the regular interruptions I actually feel like I am getting the highest quality sleep of my adult life right now.

The blackout curtains, though... The difference they made from one day to the next was immediately obvious. My wife and I both woke up feeling more refreshed, looked at each other and said, "Why did we wait so long to do this?"