In order to carry out the routines and activities you need to carry out safely . I should mention that the reason overhead lights are problematic is the same reason why sunlight is so great early in the day , which is that the cells that is the neurons that can wake up your brain and body through activation of the circadian clock reside mainly in the bottom half or two thirds of your neural retina . And the way the optics of your eyes work is that the cells on the bottom half of your eye view the upper visual field .
So viewing bright light in the late evening hours and nighttime hours is really not good for your sleep quality and your ability to fall and stay asleep . So for most people , a simple rule of thumb is going to be avoid bright artificial lights of all colors and in particular overhead bright artificial lights between the hours of 10 p.m. and 4 a.m. That's right between 10 p.m. and 4 a.m. Avoid those bright artificial lights as much as possible . Use only as much light as is absolutely necessary .
So this is a beautiful adaptive mechanism that allows these cells to respond to overhead light from sunlight in the early part of the day and throughout the day . But in the evening , if you have bright artificial lights on , and those bright artificial lights are overhead lights , it's going to more closely mimic what sunlight does in the evening time . And that turns out to be a bad thing if your goal is to eventually go to sleep .
So candlelight is fine , of course , be cautious with open flame , but candlelight is fine , moonlight is fine . Dimming , artificial lights is fine provided they're dimmed way , way down and again , try and avoid using overhead artificial lights . The absolute worst lights are going to be overhead fluorescent lights of the sort that you would have in the supermarket or uh that you would see at a gas station or something of that sort .
And ideally the lights that you do use , you would place low in that physical environment . So you would try and not use overhead lights , but rather rely on desk lamps or lights even place low to the floor , even on the floor . If you are going to use light at night .
