I use a heart rate monitor while I run. It is an optical unit. I have run a battery of personal tests on it and it is at least as accurate as my old chest strap monitor. Sometimes I wish it weren't accurate, lol. One thing I did discover with my unit is that you have to have is on fairly snuggly, never uncomfortably, in order to get the most consistent results. Maybe the lady in the CNET article needs to try that. Most of the max heart rate formulas start to fall apart if the wearer is older and that can be a challenging thing to work around. It seems there were two big ideas when the folks who developed fitness zones undertook that task. First, at what heart rates will people be at safe efforts with. Second, based on measurements taken in the past, at what heart rate zones will optimal physiologic changes occur, i.e. at what range will people burn fat the most efficiently, at what zone will people's aerobic physiology develop optimally, and so on. It seems like more than coincidence that optimal development occurs at fairly low, safe, heart rates. Maybe part of our biologic design? Heart rate zones are controversial in our, convenience oriented, western modern day society because we can take great expenditure of energy for granted, and moving more slowly isn't as fun. Take away all of the conveniences of modern western life and plunk us down in the grasslands of Africa and our view of energy expenditure will change overnight. Hope this helps.