Adenosine is an important chemical known as a nucleoside that exists naturally in all cells of the body.
In addition to being a neurotransmitter, adenosine is classified as a chemical known as a xanthine.
Every cell in the body contains some adenosine contained within DNA and RNA.
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Then, adenosine levels decrease during sleep.
Therefore, scientists have long extrapolated that high levels of adenosine in effect cause sleep.
The various stages of sleep all serve distinct purposes for rest and rejuvenation.
In stage 1, heart rate and breath slow while the muscles relax and sometimes twitch.
In stage 2 sleep, the body temperature drops while heart rate and breath slow even more.
Eye movement stops during stage 2 sleep.
Stage 3 is thedeep sleepnecessary to feel refreshed in the morning.
In REM sleep, the eyes move rapidly, and breath is fast and irregular.
Heart rate and blood pressure are close to what they are when you’re awake during REM sleep.
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