Sleeping: Adenosine and Melatonin

Dr. David Seiden, Medical Director of the Pembroke Pines Sleep Center with Baptist Health South Florida, explains adenosine is the breakdown product or byproduct of cellular metabolism. "By the end of the day, adenosine levels are quite high, and as our adenosine levels rise, it tends to make us sleepier. That's very interesting, because caffeine acts by blocking adenosine levels, therefore it keeps us awake".

He also says we have a circadian rhythm, it is genetically programmed and it is mediated by melatonin. When there is a lot of light during the day, signals are sent to the retina, and then to the middle of the brain. Those signals are to tell the pineal gland to suppress melatonin, but at night, with less stimulation of the retina, melatonin is then produced.