I'll just leave this here:
http://www.webmd.com/back-pain/news/...y-sitting-back
Reclining for the win! Office chairs, car chairs, movie theatres - it's all good!
I also get up frequently on long flights. I try to take a stroll at least hourly. It's good for your legs and back to get up and move around. Drinking tons of water helps. It's so dry up there and having to constantly use the washroom makes sure you stay moving. I'd rather not be dehydrated after a long flight just to be polite. And shoes, those come off instantly. Shoes are just the man bringing you down!