Gaining Years or Subtracting Them?

I often wonder if we are adding years to our life by living here or taking them away? On the one hand we are exercising in more practical ways here.  Without a car, we bike or walk  nearly everywhere so by default even if we don't "workout" we are using our bodies for things in our daily life that we typically wouldn't do in Seattle.  We have to move to get anywhere - to drop off or pick up the kids from school, to get groceries, to go to Dr. appointments or school meetings or soccer practice or anywhere we have to walk or ride at the very least a mile each way.  Our brains are constantly taking in new things and for me a new language daily, hourly, sometimes by the minute.  That has to be better for reducing memory loss and warding off Alzheimer's  disease than doing crossword puzzles or sudoku games, right?
But then I think about how old my body feels when  I ride my bike over cobblestone roads and my teeth chatter and my back twinges and moans.  My neck feels a shot of electricity and my arms and shoulders shake.  I hate riding over cobblestones.   And I've had two, actually three falls on my bike.  None of them major and no broken bones but bruises for sure.  Just before we returned to Seattle I was riding with Benjamin home from school and our bikes somehow collided just a bit and I went flying into the street.  He stayed upright but I went skidding across the street.  My bag, which was in my bike basket, went flying into the street as well.  Thankfully there were no cars going in either direction which would have made it far worse.  The bike and my whole left side were pretty banged up and my nerves were shaken but I was OK. 
This past week Marty and I spent a couple of hours at the lake (Schlachtensee) without the kids while they were at school.  We swam across and back in glorious 85 degree sunshine.  While we were swimming I thought how good this is for us.  To have the time and energy to be able to enjoy a swim in the lake mid day, mid week.  I thought, oh, this is a time we are definitely adding years to our life.  But then, on the way home, my bike tire caught the edge of the bike path so that when I over-corrected sent me into the hedge/chain linked fence.  I didn't fall outright but ended up with a couple serious bruises on my thigh where I ran into my bike.  So, maybe that day we ended out tied - added a bit while swimming in the lake and took them away after running into the fence.  Give and take... hopefully in the end we will have added more years, memory and life to our lives than taken away.