I know of melanopsin, a photo pigment in mammal eye that helps regulate circadia
ID: 31775 • Letter: I
Question
I know of melanopsin, a photo pigment in mammal eye that helps regulate circadian rhythms. It responds most strongly to blue spectrum light. There have been experiments that demonstrated that intensity of light is proportional to the impact on circadian rhythm regulation/ melatonin suppression.
This is why I'm interested if there is some optimal illumination intensity that has been demonstrated to result in better health/cognition in humans. I heard anecdotal reports of full spectrum lighting improving attention in classrooms, but is there some chart or figure which says how much is "too much light".
Explanation / Answer
It seems there has been some work done on too much light affecting human health, but in regards to lack of darkness at night, rather than too much during the day. Without the appropriate amount of darkness at key times melatonin production and the major clock regulator or SCN can be disrupted and lose sync with the peripheral clocks, for a comprehensive article with loads of information and other links to studies done on this topic.
This part in particular illustrates some of the problems associated with too much light:
"Overexposure to sun-mimicking light is also believed to play a role in the increase of insulin resistance, type 2 diabetes and obesity in developed countries (where round-the-clock illumination is more prevalent). Some research also shows that too much sun-mimicking light ups our craving for carbohydrates.
Before humans started cultivating grains, carbohydrate energy was available only from spring to fall. In response, our bodies evolved to stock up on carbohydrates during the growing season to prepare for winter, when no carbohydrates were available. In turn, we didn