As someone who has worked alternating day/night shifts for several years, I can anecdotally say that going to Amsterdam a few weeks ago from SF completely and utterly kicked my ass, and then getting back was worse. Much worse than alternating day/night shifts in the same week. I was not nearly expecting anything like that.

> Really? I thought jet lag was based on your sleeping hours, not the sunlight hours.

But sleeping is a daily thing, and the day is based on the rhythm of the earth going round the sun. There's more to it than just missing some sleep (or getting some extra).

> Does that mean I can get jet lag just by opening or closing a set of effective bedroom window blinds?

1) No. Because closing the curtains does not make the sun go down. Next time you open them, the sun will still be behaving according to your mind's schedule (Assuming you weren't on a plane when you closed the curtains).

2) Yes. The above is not completely accurate. If you live in the dark (or with red light only) your day rhythm will drift by +1 hour each day. Do that for a week, come out of your cave, and you'll have a jet lag (without having flown).