Because the mixers กาเฟอีน กาเฟอีน กาเฟอีน is a component which will stimulate the central nervous caused awake feeling refreshed, but sleepy lost just a short period of time only.
For drinks with caffeine Caffeine is a component The caffeine to stimulate the central nervous system. Awake feeling refreshed lost cause drowsiness, but it's only a short time only.
Because mix drinks caffeine, caffeine content is a component which caffeine to stimulate the central office, causing the alert, I feel refreshed. Lost sleepy but only a short time.