Great Seattle Times article on some peoples' natural propensity to be early risers and others' to be night owls, and hwo to change from a night-person to a day-person. Good, popularist brain-hacking for the Eastern Standard Tribe.
In college, many people find their optimal rhythm and harness it. Larks join the crew team; owls discover they study best over the midnight oil. These morning folks may be asleep by the time the kegger is raring, but they will be vindicated when it's time to enter the real world. They show up before the boss and look like go-getters. Owls can either find a night-shift job, one with a flexible schedule or reset their body clock to join the 9-to-5-ers.
A body-clock mismatch also can be hard on lovebirds. If she wakes up on New York time but his clock is set on Pacific, she'll view him as lazy, and he'll grow bored spending evenings alone.