Today my fitbit app suggested a cardio load for me of 57 to 71. I have no idea what this is, and fitbit isn't terribly helpful about this. I'm 68, 169 lbs and working on losing weight with a 1200 calorie diet, logged myself as sedentary, and generally get between 4 to 7 miles of walking in a day, (10K + steps). It is not zone points, because today (so far) my zone minutes are 46 and my cardio load is 27. I think I'm doing pretty well to walk 5 miles or so a day. Can someone let me in on why fitbit just doesn't set a zone minutes goal? I seem to be pretty far from reaching the recommended cardio load of 51, and I've walked 3.7 miles so far today. I probably will walk twice more today but it doesn't seem like that will do it.