Can't sleep: the mystery of love and sleep deprivation

Out of nowhere, I got to wondering why people can't sleep when they're falling in love.

There's a saying that seems to explain this: "You know you're in love when you can't fall asleep because reality is finally better than your dreams."

That sounds like a good explanation to me.

Yet how come when one falls out of love, a person can't sleep too? Ask anyone who experienced heartbreak. They'll be quick to tell you how they can't sleep properly after breaking up with someone.

Perhaps in cases of break-up induced sleepless nights, my sister Lynn is right on target, "...reality can be worse than your nightmares in the same way that truth can be stranger than fiction."