In 2004 I had three bulging disks in the lower back. I went to a physio who prescribed me a set of exercises to improve "core strength", using the muscles running along the spine to hold the spine in place. He said the damage probably came from inactivity, as I was working on computers all day and all night, sitting and doing little else. From being unable to walk, stand or sit, I progressed to being able to shuffle, and now I can walk and run. But I find if I don't walk most days for about 40 mins, then the pain in the lower spine begins to come back. Just a bit. Just a reminder of what could be in store if I don't get my shoes back on.