Apr 2013

Circadian Rhythms – How Light Affects Sleep

Circadian rhythms are internal biological rhythms that are controlled by an external factor which in most cases is daylight. Life on planet Earth has been affected by these circadian rhythms since life began. We are pre-programmed by hundreds of generations to be affected by the 24 hour day/night cycle of light and dark. We now have many sources of artificial light that we use every day. These sources of light are impacting our lives, specifically the quality and quantity of sleep we get.

Sunlight qualities changes as day progresses from sunrise to sunset. As sunlight travels through he atmosphere it is refracted and reflected. In the early morning there is more of the blue spectrum in sunlight and in the evening there is more red.

Melatonin is a chemical produced by the pineal gland in the center of the brain. It is necessary for sleep. Blue light suppresses melatonin production so exposure to blue light before bedtime interferes with a restful night’s sleep and disrupts the circadian rhythm. In nature there is less blue in evening sunlight and more in morning sunlight. That makes it easier to go to sleep in the evening and to get going in the morning.

What do we all do every evening at home…watch TV and plan video games on computers. TVs and other video screens emit light in the blue end of the spectrum. This causes low melatonin which results in sleep problems. And this is especially problematical for older people because as we age we produce less and less melatonin naturally. Maybe putting kids in front of the TV just before bedtime might not be a good idea!

More information will be forthcoming in future blog posts. In the meantime be sure to visit FoggLighting.com and like us on facebook.