Calorie Burn Accuracy

First time using the F7XSS paired to the rowing machine on Wednesday.  Obeservation:

Garmin calculated 943 calories burned, compared to Concept2 PM5 calculated 1807.  Note that I was wearing my Garmin HR strap (which I do for all rowing sessions, weight training, and HIIT workouts) and was paired to both the FENIX7 and the Concept2 ERG.  Average heart rate was within 3bpm between Garmin and Concept2 for the duration of the row, yet Garmin FENIX 7 estimates half the calories burned.

All other metrics collected by the FENIX7 were accurate, to include stroke rate, distance covered, 500m split pace, and power.  Attached image is the same rowing session from each data source (Garmin FENIX7 on left | Concept2 PM5 on right).

Anyone else noticing this with fitness equipment paired directly to the watch?

  • 2 weeks ago my Fenix 7 stopped recording calories burnt correctly when doing spin. It’s gone from 500 to 90 calories burnt, all other stats are correct. Am sure it’s a setting that’s changed when I hit start indoor bike last time but not sure what it was. I’m not using my HR strap btw 

  • Based on the power data, which may or may not be accurate as it is a calculated value in Concept 2, with gross metabolic efficiency rating of 20% you'd get a calorie burn of around 1450. Normally gives me about 550 calories per hour Kayaking at just under 3min/500m and 600 calories per hour cycling with a power meter at Zone 2.