I do tai chi chuan, with a teacher that insist on having the right (ie efficient in combat) postures. That's pretty tough to reach (you need a lot of muscle flexibility); that is, years of mild training. Although I'm nowhere near having the right postures, working on that twice a week makes a huge difference on my back pain. I also do standing tree posture chi kung, 20 minutes every working days. Helps a lot

And I started to do all of that not because I love martial arts, but because it relieves my pain significantly. If I had the time, I'd some some swimming too and some running to help my heart too.