What is the central idea of the first section:
when and how often do we dream?
most people experience at least one hour of
rem sleep every night.
o
rem sleep was discovered by researchers at
the university of chicago.
o
people dream every night during a sleep cycle
called rem sleep.
people dream from 5 to 20 minutes within each
sleep cycle.

The central idea of the first section of "When and How Often Do We Dream?" is that People dream every night during a sleep cycle called REM sleep.

Explanation:

During the REM sleep phase, one must dream for about 4 to 6 times within a single night. The fun fact is that the humans often forget what they are dreaming about. Just because we don't remember it doesn't mean we don't have a dream. While sleeping, a hormone secreted by our brain named norepinephrine becomes dormant which makes us to lower our concentration while dreaming. This makes us to forget most of our visions and dreams (Humans forget almost 95% of their dreams in their lifetime).

REM is often associated with the Rapid Eye Movement which makes us to move our eyeballs in random directions and one must notice an increased brain activity while sleeping. A common study shows that people are often intented to dream during their REM stage.

There are almost five stages of sleep. They are Alpha and Theta Stage (a stage between awake and asleep), Sleep spindles (our body paces down), Delta waves (stage between the light and the deep sleep), Delta sleep (Short term deep sleep) and REM Sleep (Paradoxical and Paralyzed stage, Deep sleep state). You will feel messed up when somebody wakes you up in the REM stage.

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