The benefits offered by wearable devices seem limitless, and for many people, the devices are really chic. These wireless gadgets can track the number of steps people take each day; measure their heart rates, the number of calories they ate, or the amount of energy they expended; or access data by using cloud computing. Wearables--bracelets, rings, eyeglasses, necklaces, shoe clips, and more--enable individuals to read, text, send e-mails, stay connected...