Bests & Worsts Reviews from Amazon

The product does not capture heart rate accurately, despite referencing their online user guide as instructed by customer service in order to ensure proper wear and usage. Please see attached photos of a treadmill run in February. I alternated between sprints and hill walking in order to get my heart rate up. The treadmill heart rate reflects my Polar chest strap reading (which, based on perceived exertion standards, felt reasonable.) And no, I do not run like Phoebe 'Friends'; results were just as subpar on the bike. The FitBit is regularly lower than the Polar or cannot capture a reading at all. I did contact Customer Service who provided me with a detailed explanation of "how our capillaries expand and contract based on blood volume changes and how the PurePulse LED lights reflect onto the skin to detect blood volume changes and finely tuned algorithms are applied to measure heart rate automatically and continuously". Perhaps so, but after two months of wear it does not seem accurate. The nail in the coffin was today at the doctor's office when their fingertip heart rate monitor read 60 and the FitBit Chart HR read 99. The nurse and I had a good laugh and I'm still searching for a product which accurately measures heart rate without a chest strap.