Great thread! You've all inspired me. I'm a 57 y/o female and I daily enjoy four miles of walking/running depending on my energy level. My best days are 100 steps of walking, followed by 100 steps of running, back-to-back. If I'm walking, I like to listen to educational podcasts. I just downloaded a new app called Blinkist which offers 15 minute audio summaries of top selling non-fiction books. I can't wait to play with that on my trek today.
Every other day, I do about 40 mins of strength training along with my walk. I firmly believe that of all of our strategies, none has more scientific proof of efficacy than exercise.