Human dreams are a strange and mysterious occurrence, which science knows little about. Why do we see people and places that we have never seen before? Why do we dream of events that we are not actually part of?
These questions still do not have any answers. The longest time anyone has been awake, registered so far, is 18 days, 21 hours and 40 minutes. This time was recorded while he spent the most time sitting in a rocking chair.
It is not possible to determine whether a person is sleeping without doing a medical examination. Very often, people fall asleep for a few seconds with their eyes open, if they are incredibly tired.
If when you go to bed at night you fall asleep in less than 5 min, your body has a desperate need of sleep. The ideal time needed to fall asleep is between 10 and 15 min.
This means that you are plenty tired to sleep soundly throughout the night, while also not feeling sleepy throughout the day. The birth of a child leads to 750 hours of lost sleep for the parents in the baby's first year.
REM (rapid eye movement) sleep goes through cycles throughout the entire night, lasting a total of about 2 hours and beginning in the 90th minute after you fall asleep. A person dreams in all phases of sleep but cannot remember every dream.
In the slow wave sleep phase, dreams are more like deep thoughts, while those in REM sleep are quick and illogical. No one knows whether animals dream but they have 2 phases of sleep as well.
Elephants sleep standing up during the NREM (non-rapid eye movement) stage and lie on the ground during REM sleep. REM sleep significantly helps brain development.
There is no explanation for the fact that if a spot of bright light is shone on the back part of the knee during sleep, the rhythm of dreams and biological clock of the person go out of balance.