As the heart rate sensor is still a bit unreliable, it may be improved by using a community approach gathering a lot of data and building a prediction model from it. A discussion on how to get hr data from pinetime has been initiated here theironrobin/siglo#33 @ siglo and daniel has been very swift in responding here wasp-os/wasp-os#204. So even though downloading data as raw as possible from the pinetime is possible there is still the need to gather the true actual hr eg measuring ones pulse for 60secs. This is currently quite difficult, max screen timeout after 60secs, no cue when measurement of hr starts @ infinitime. So the easiest would be the latter in addition to an increased timeout, though a better solution would be a temporary heart rate collection app, where you are asked to store your heart rate measured by hand after 60secs infinitime collecting data.