ARE YOU A STEPS-PER-DAY COUNTER? My Fitbit tells me how many steps I take each day. It has a suggested default of 10,000 steps. Some days I reach that amount, but most days I don’t—but then it doesn’t take in my biking or swimming activities very accurately, which I think should also count. You might use a step counter such as your smartphone or a wearable device.  And you may wonder—especially as a senior—how many steps per day to shoot for. I found an October 1, 2019 online article by Anthony L. Komaroff, M.D. Editor in Chief, Harvard Health Letter, that...