Stretch yourself

I keep hearing the benefits of exercise from a wide range of sources. It can ward off everything from heart disease and diabetes to hypertension and stress. So why is it so difficult to put exercise into a daily routine? Perhaps it is because it offers one more thing I have to do when life is already speeding along with a thousand other demands.
I picked up a free app last week at Starbucks for "Pocket Yoga" with a great image of someone enjoying a superior stretch.  Now if I could just find the time to download the app.
Maybe I will get to it after my walk. 
People in my neighborhood look at me funny because I like to book-walk. I combine a beloved hobby— reading— with much needed exercise. Yes, I sometimes clonk my head on a low-hanging tree branch, but I have learned to keep an eye out just above the printed page for uneven sidewalks. Some people consider me a danger to others as I stride along with a nose in an interesting novel. Who knows what obstacle I might encounter.
Those of us wrapped up in busy lives sometimes take risks as we multitask.
What other solutions do busy people use to combine something they enjoy with something that is yet another "have to do"?