The external factors that effect our lives and the different rhythms that we as human beings experience, whats that word ah yes zeitgebers. The one that effects our lives and daily patterns that most is the light dark cycle of the planet earth. This is what effects our sleep cycle and what makes us sleepy at dark and fresh and awake in the light. But what used to be the only big light source (the sun) and therefore natural timings does not so much the only light source any more.
Modern times means that man made lights also effect our patterns. The problem is that our bodies are not that smart to be able to distinguish between natural light and that un-natural source such as televisions, and anything that is powered by electricity and is keeping us up well in the night. Our bodies just are not that smart. Our bodies simply react to a source of light and that's it. Whether its the blue light that comes naturally from the sky at midday or from the computer screen at midnight to the human body its all the same.
How blue light and where it comes from is very important to how healthy we are as human beings. Of course as with anything else moderation must be applied if it is to have any long term benefits and not the reverse negatives. the problems occur when we have too much or too little. This applies to anything related to our bodies as humans. there is always an optimal range and its best if we try to keep within that limit. What blue light does is it keeps an eye on the levels of melatonin. This is the hormone that is responsible for sleep. when we are exposed to blue light we actually limit the production of melatonin. In effect this causes the human body to think its day time and so the body stays alert and awake.
When of course there is little or no blue light then melatonin is produced heavily causing us to get sleepy. This is perfect situation to match the light dark cycle of planet earth. This is what nature intended and is how we have evolved over millions of years. The problem is however related to the excess of blue light that we have in modern times. In day time of course this is natural we should be awake but at night time when human body should be getting ready to rest and sleep we are busy keeping ourselves awake with different technology that is emitting blue light. This causes our patterns to severely mess up and our sleep cycle suffers as a direct result.