More wrist-based heart rate monitors are hitting the market, letting you gauge your fitness with a quick read of your pulse.
http://www.pcmag.com/article2/0,2817,2404445,00.asp
But as Sharon Profis discovered after a visit to the doctor, these optical monitors may need more R&D. There may be a problem with your fitness tracker: it could be misreporting your pulse.
You can find the results below, but it seems the optical sensing technology used in many of today’s new, wrist-based mobile heart rate monitors is sometimes inaccurate. That’s in comparison to time-tested EKG machines (or the heart rate monitors that emulate them), which sense the electrical impulses that trigger your heartbeats.
http://www.cnet.com/news/how-accurate-are-wristband-heart-rate-monitors/