Personally, I find a good, medium-length swim (about 25-30mins. A long swim being 35-60 minutes) does the trick after a long flight.
It’s easier on the joints, gives you the same endorphin rush, and you don’t get lost in an unfamiliar city. What’s more, you can hang around the foyer without repelling guests and staff alike with your sweat and odour.
Best of all, if any air crew are staying at your hotel, you get to impress the perma-tanned Trolly Dollies, lounging poolisde with their vapid glossy mags, with your strokes (no pun intended).
The only thing is, so few four star hotels,especially in Europe, have a decent-sized lap pool. It isn’t so much of a problem in SE Asia, though.