The TomTom Runner Cardio is probably the most important development in personal heart rate monitoring since Polar started the ball rolling in 1982. Since then pretty much every sports watch has relied on a wireless sensor attached to a chest strap for heart rate measurement, but TomTom has taken that conventional rulebook and torn it to shreds. You see the TomTom Runner Cardio is a landmark product; a device that raises the bar, changes the game, and ignores the confines of conventional wisdom. Like all great innovators, TomTom looked at how things were being done and decided that there was a better...