Hi - I've checked my resting heart beat over 3 mornings and on average I get 60 bpm (I'm 69 years, male) On my last 2 runs of 2 kilometers each, my average bpm on TomTom Sports shows as 45 bpm, falling as low as 37 bpb at some points, in fact at around that number for most of the run. I'm using a TomTom Sports Watch and TomTom heart rate monitor. When I started out this morning my bpm was 77 but within a minute it dropped to 39. Seems to me that something is wrong, either the technology or me. Any thoughts appreciated. I make sure the HRM pads are wet before I start.