For the past couple months I've noticed my Forerunner 235's chart of HR for the day usually has a huge spike over 200 bpm during the 30-45min or so that it is off my wrist and on my counter charging. This screws up my estimated daily calorie burn since the unit uses HR to adjust estimated calorie expenditure, which is the whole reason I thought the 235 would be nicer to have than the 230---I use a chest strap for actual exercise. I've tried pointing the sensor up in the air or down at the counter-top but it seems to happen either way. Anyone else seen this?
Here's an example HR chart for a recent day that did this. I usually charge while I shower after going for a run, so the lower peak below just over 150 is my actual run, using chest strap, and the red spike to 200 is a complete fabrication. Until this started happening this year, my calorie burn estimates were very consistent on days that I ran but on days when this spike happens they can be too high by 400-600 calories (20% or more).
