It is something I have learned over the last two years. I understand that a human being is naturally tired and ready to sleep as darkness falls. However, considering the amount of artificial light which we expose ourselves to, it is disrupting our natural cycle of when we feel we should sleep.
In other words, we are tricking our own bodies out of much needed rest.

I know of many people who take their phones to bed but do not actually fall asleep until several hours have passed. How can a body replenish and repair itself if it is not getting adequate rest?