Editing Sleep inertia (section)

=== Caffeine ===
[[Caffeine]] is a [[xanthine]] derivative that can cross the [[blood–brain barrier]], as well as the most widely-consumed [[stimulant]] compound, present in therapeutic quantities in a variety of food and drink, including [[tea]], [[coffee]], [[soft drink]]s and [[chocolate]]. The caffeine present in coffee or tea exerts its stimulating action by blocking [[adenosine receptor]]s in the brain. By [[Antagonist drug|antagonizing]] the adenosine receptors, caffeine limits the effects of adenosine buildup in the brain and increases alertness and attentiveness. Previous research has shown that coupled with a short nap, consuming caffeine prior to the nap can alleviate the effects of sleep inertia.<ref name=":02"/> Nonetheless, individual degree of consumption and [[Drug tolerance|tolerance]] to caffeine may be responsible for variation in its efficacy to reduce sleep inertia symptoms.