Via Kevin Drum:  http://motherjones.com/kevin-drum

A lot of people believe that if you, say, travel to Europe, all you have to do is force yourself to stay up all day on your first day and you’ll be OK. You won’t be. Here’s why: twice a day your body releases stimulants that wake you up. This is (awkwardly) called “clock dependent alerting,” and it happens once around 6 am and again around 7 pm or so — though this varies from person to person. So when I travel from California to Paris, even if I stay up all day and get to sleep just fine at midnight, around 4 am I’ll wake up. And for the next three hours, no matter how hard I try, I can’t get back to sleep. Around 6 or 7 am I can, but by then it’s time to wake up. Result: I’m completely wiped out for the rest of the day.

So here’s the answer: sleeping pills. Get a good quality prescription sleeping pill and take it when you go to bed even if you don’t need it to fall asleep. You don’t. You need it to stay asleep. I now take a sleeping pill every night for about a week (plus one on the plane over) when I travel to Europe, and it’s like a damn miracle. I literally have no jet lag at all.

(Obviously this depends a lot on where you’re traveling to and from. Going from LA to New York, for example, I take a pill because my evening stimulant rush hits around 10 pm and won’t let me get to sleep before 1 or 2 am. So in this case, the pill does help me get to sleep rather than keeping me asleep. If you’re traveling from the East Coast to Europe, ditto. If you’re traveling west, it’ll be something else. But the arithmetic is fairly easy to figure out. However, you really can hardly go wrong by just taking a pill an hour before bedtime and not fussing over it.)