PhotoperiodEffect.com

5. Artificial light is just light. It doesn't have any frequencies of light that the sun doesn't. So isn't it a bit superstitious to single out artificial light as a possible problem?

Yes, the frequencies are the same, or close enough for horseshoes – it's what scientists call the photoperiod that's the problem. When we extend our period of light, there are consequences to the way our bodies work, and many chronic problems (I hope to convince you) can and do result. If instead of electricity, we used giant mirrors in orbit to extend our daylight by the same amount of time, we'd still have the same problems. It's not what's “in the light”, or even the mix of frequencies (or if that's a problem, I haven't found much evidence of it.) It's only the length of time we spend in light, compared to the endless generations of humans and other mammals that preceded us, and gas and electricity, that causes the problems.

That having been said, very bright light, and blueish light, does help to set our biological clocks, as does exercise and eating. It's a good idea for all of us to get out into the sunlight every day and not rely on artificial lights entirely (or to buy a very bright light.) Of course, we need the Vitamin D, which has been shown to be helpful in many chronic illnesses, but we need the bright light to regularize our clock and get us to bed, and darkness, a little earlier, too.