In our industrialized society, we have lost natural twilight, the time of night when the moon rises and we move indoors to sleep. Twilight is when work is done and the body prepares for sleep. With indoor lighting, the natural stimulus that leads to sleep is disturbed. One of the most prevalent causes of insomnia and other sleep disturbances is the addition of light past the time of twilight. This so-called light pollution has been blamed for much illness, especially the loss of the natural sleep cycles. Viewed from space, out globe is illuminated around the clock, especially in the urbanized nations and continents, such as the United States and Europe. (See link at bottom of page for a website that shows this map.) Changing the way we light our homes at night can recreate an indoor twilight, and improve sleep.
It is no mistake that Forks, Washington, is the setting for books and movies about vampires who sleep all day. Twilight is the quality of the daylight all day long in Forks, where the winter sun shines for only eight hours. The dim foggy haze that hangs over the area is no brighter than twilight on a summer evening, and this is conducive to sleep. Visitors to this area find themselves feeling groggy and sleepy in this environment because the stimulation of the pineal gland, which wakes the body up, is not present. Most North Americans spend long evening hours extending the days with indoor light, in Forks as well as in other less misty cities. This is the time of year when stimulating an indoor twilight is most important.
Light from electrical lights reacts with our eyes, causing us to see, but it has other deeper effects on the body. The pineal gland is stimulated by light, both daylight and artificial light, and this is what sets up our daily Circadian rhythms that tell us when to wake and when to sleep. Electric lights at night upset this rhythm by telling the pineal gland that there is still daylight out and to stay awake. The pineal gland stimulates the creation of the hormone melatonin, and disruption of this cycle prevents sleep.
To create better sleep, a home needs to recreate natural twilight. To do this, the indoor lights need to be turned down or off at least a half hour to an hour before sleep. Cover windows so that ambient light from the street will not filter in. The darker your bedroom, the better. Filtering noise is also important. Do not watch television for an hour before bed. Any light will stimulate the pineal gland and upset the sleep rhythms. It is also advised to go to sleep at the same time each night, or within one hour of the same time, year round.
The more that a home is in synch with the natural levels of light outside, the better the conditions for sleep become. Stimulating an indoor twilight will help provide better sleep, preventing insomnia and other sleep disturbances.
Use this site to monitor the night sky in the World: Satellite monitoring of the artificial night sky brightness and the stellar visibility