Pulse Sonic K920d

chrisclima

I recently bought the pulse sonic K920d to track calorie burn during exercises as I found the info on MFP too high. But I'm struggling with this - everything seems to be working fine, except for the calorie info. I tested it at a spinning class, my average heart beat was 160bpm and the calorie burnt for 45 minutes exercise was 70. Can this be right??? It seems that people burn more calories sleeping than I do on spinning classes... Am I missing a trick here?

I sent the first one back, as I thought it was defective, but the new one seems to be working the same way.