zlacker

It seems logical and reasonable to me that humans will be affected by how much daylight there is and how bright it is. Imagine if the earth began to recede from the sun, such that every day gradually became shorter and dimmer. (Set aside climate and crop disaster and consider the psychological effect on humans.) Humans have a daylight-triggered circadian rhythm: at night the body produces melatonin which promotes sleep, and at dawn that production stops. As the world falls into more and more darkness, what will happen to such body mechanisms? Folks living very far north can probably speak to this; high enough and you see complete darkness in winter for months at a time. Humans aren't adapted to that, and I would hypothesize that the same mechanisms that contribute to circadian rhythm will be maladjusted to that environment.

It's also known that the body's response is based on light (known to impact melatonin production), and that light treatment in the day might ameliorate whatever effect the dim light or darkness has.

The lights we're talking about can, at best, light a small area around them to a brightness that's 10% daylight. The most extreme lamp he mentioned does 30%, again in a small area. Hardly a lighthouse.

It seems natural to me that if you hypothesize that lack of sunlight contributes to sleepiness or depression in winter months, then you'd want to treat that with something approximating sunlight as best you can, or 100,000 lux.

So we don't know for sure whether this works or how effective it is, but there are good theories behind it to test. Let me put it this way: suppose I put a lamp with 100,000 lumens in your bedroom and activated it shortly before dawn or, just for fun, at midnight. Would you wake up? It's clear that light does something to wake you up, and that it's harder to sleep in bright sunlight in darkness. Well, winter is short and dark for many people.