Nowadays, people often complain that it is difficult for them to get enough sleep, and the quality of sleep is often poor
In some rural areas where there is no electricity, the average sleep time of people is much longer than that of their peers living in cities
 Some experts believe this has something to do with many products of modern technology, such as Changming street lamps, televisions, computers and mobile phones, where the light generated by artificial light sources and electronic devices disturbs sleep and makes it difficult for people to fall asleep