13 minutes of walking for me and my lower back is killing me. I guess I'm glad I've decided to start walking since obviously I'm barely in shape to take a long walk if I felt like it. Think I need to start back on the bike too, though. I'll finish this week out trying to walk daily and maybe throw in a little time on the bike, and if that goes well I'll try to keep up the walking and add 5-10 minutes on the bike as well on a daily basis next week.