Want to know why all those endless cups of coffee helped you to stay up all night while you crammed for the CAT entrance?
Caffeine works by blocking your brain’s natural sleeping potion, says researchers at the University of Texas Southwestern Medical Centre. They found that brain cells are overworked; they release a chemical called adenosine, which re-enters cells, lulling you to sleep. Caffeine bars help the adenosine’s return, so your brain cells keep working through their fatigue.

Via