ajGoes

True, but moving from one to another can't displace you more than twelve hours in one direction or the other. A six-hour change is half of that, 50% of the maximum possible.

I wish I was one of those people who adjust so easily. It always takes me a couple of days to recover even from the one-hour change to daylight saving time, and two or three days from the three-hour change from Eastern to Pacific time in the US. On the other hand I managed to function reasonably well after making the plus-thirteen-hour (i.e., minus 11) change from Ohio to Tokyo. I was only on my own from the airport to the hotel where my friends picked me up, though. From then on, all our many trips on public transportation were in their seasoned hands. I'm sure I'll have had to exert myself considerably to navigate the Tokyo subway if I manage to get back there, now that my friends have moved back to Ohio.

Psychological studies and accident statistics indicate that average people take quite a while to adjust to time changes. We all like to feel that we're above average. I'm perfectly willing to concede that, in this area anyway, I'm pretty normal.

I'm dubious that training can really alleviate jet lag. I'm sure people can train themselves to compensate so as to minimize the risks from fatigue, and that there are strategies that will at least modestly improve the adjustment. (Being aware that you're fatigued and more prone to make errors is a good start.)