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I notice that when having slept for a little bit of time and I am drinking caffeine, I may get instantly alert, but after few minutes after drinking the coffee, I still feel extreme urge to sleep!
Can caffeine be the reason for such a reaction? Is there any documented mechanism?
This is a documented phenomenon. Some people experience paradoxical reactions to caffeine, and other stimulants such as dextroamphetamine (1).
A theory posited by this non-medical source (which does not cite sources), suggests that the blocking of adenosine receptors by caffeine causes the body to compensate by producing more adenosine, or increasing the number of adenosine receptors. Either way, the net effect is increased adenosine neurotransmission, and consequently, sedation.
