I always found jet lag challenging, even in my 20s, but I always needed more sleep than many people. Now in middle age I've been making monthly TATL trips for over a year and a half. I still get jet lag but my body has learned to adjust more quickly, partly because I've trained myself to get on the new schedule especially eastbound. But my sleep seems more readily disrupted in general -- I think that's a byproduct of learning to be awake on demand. It's hard on the body.

The only time I didn't experience jet lag traveling TATL was flying from the US to Scandinavia at midsummer.