And when I was a young man in college, I spent many an overnight working on projects or cramming for tests, and felt none the worse for wear. Now, in my mid-50's, I take weeks to adjust to the loss of a single hour when changing to daylight savings.

There are also psychological effects. When Mrs. Deubster & I go to Hawaii (which is 2 time zones farther for us, but 4 hours travel, since we have to go east an hour to Dallas before heading west), we are always so pumped up for the trip, we have no problems adjusting to Hawaii time. But the return is always a killer. Of course, west-to-east is always much harder than east-to-west, but still, returning home from a trip is always harder even if there is no time zone change.