Does not get a pulse while running or brisk walking. Just keeps the little bars going across - forever. Tried in deep shade, nope. Tried in medium shade, nope. Tried stopped - sometimes. Only time I could consistently even get a reading is after the run, while I'm in the house cooling down. Not the application I wanted - I wanteda reasonably instantaneous reading while exercising - never got one. I replaced battery (pia!) and got a bit better performance.Wait for better technology.