This is commonly used with most office workers or for those who work in the emergency departments.
You can wake up instantly if you are needed and get out the door in less than 2 minutes.
Or you can sleep 5 hours one night, and 8 the next and 6 the next.
Most military personnel including those on submarines practice this technique.
Suffery:How many hours of sleep did you get last night?
Suffery:You need to learn how to be sleepnotic :D
Hank: Yea i know. Im still practicing it, I got up on a dime this morning :)