In the world of wearables, most 'casual' monitors are contained within a sports watch, band, or piece of jewelry and they generate accurate heart rate data by measuring blood flows with LED lights, or alternatively, electrical activity. More advanced devices require tapes across the chest, embedded with sensors that can more accurately read a heart and its rhythm. As in the case of ZDNet's Jason Perlow, for example, irregular heart rhythms picked up by his Apple Watch Nike+ Series 2 were then explored further through a chest ePatch.