I used to often wake up early, have a cup of coffee, and then fall back asleep for an hour or two. But the caffeine in coffee still had the normal stimulatory e

I used to often wake up early, have a cup of coffee, and then fall back asleep for an hour or two. But the caffeine in coffee still had the normal stimulatory effect at other times. Now I drink very little caffeine, but I still have that nighttime sleep pattern -- 5.5 hours asleep, 1.5 hours awake/alert and up, 1.5 hours asleep, and then I'm awake and refreshed and ready for the day.