Yep same prooblem here, brought a Samsung gear S3 few weeks ago, however only just started to use the exersize, the HR seems too work outside of the exersize app, however once i start to exersize and check later it shows a flat line in the exersize app for the heartrate, and fails to show up at all when i check the heart rate app, i have tried several different ways but the only conclusion i can come up with the moisture cause by sweat is causing the device to fail to monitor the heart rate, which defeat its use as a device for tracking exersize, if i dry the sensor it will start to work again for a while then fails again. It seem too be an ongoing promlem as evident in this thread, and would like to thiink this is being addressed but from the coments Sumsung are ignoring the issue. its really ashame cause i have many samsung items from enterainment to phones and the watch, until the watch i have not had problem with any item. while i hope the problem is fixed, i am mainly adding this comment to add to the thread to hope more can be done with the problem. in summing up Samsung I will not be recommending the watchs built by you until this problem is addressed and a fix is supplied.
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