Having read some of the comments over the last years or so, regarding aches and pains, I'll go back to the title of the thread:- Walking - an exercise. I've suffered myself for some months with pain in the left thigh (diagnosed by the doctor as sciatica, but as a muscle prob. by the physio). Acupuncture has made an enormous difference, and a short manipulation by a sports injury practitioner saw off the last of the discomfort last week.
However, what I did find during the months of treatment was that a short walk first thing made all the difference and made me much more mobile. Add to this the observance of Spring emerging with the sight of birds nests being built, butterflies, flowers etc. it was an excellent start to the day. If, for some reason I was unable to walk first thing in the a.m., the pain remained for much longer during the day. So the benefits were twofold - both physically beneficial and mentally uplifting. I rest my case re the benefits of walking!!