Hi,
So I believe the proble is with firstbeat?
I have a Fenix 6 Pro and an Edge 830.. When I do a workout using a powermeter I get a reading of KJ on the detailed breakdown page. Until recently it correlated well with the calorie count on the main page. Now my calorie count is way higher. I understand that Garmin includes metabolic carloie burn but I wondered if it was easy to disable that and go back to using KJ to calculate calorie burn.
I had an 80 minute indoor ride yesterday. Here are my stats....
Human efficiency on a bike is, so I've read, put at about 24%. The power meter measured net work done at 712kJ. That means 2967kJ gross effort, allowing for inefficiency.
Divide that by Phil's conversion rate of 4.184 and you get 709 Cals.
Add approx 116 Calls for 80 minutes of metabolic life (at my BMR rate of 87 Cals per hour) and you get gross Cals of 825 vs 828 recorded by Garmin. Not much in it. In fact, nothing in it if you take the original kJ figure instead of the one marked up and back down again.
Footnote. As a convenience it is reasonable to assume that working Calories burned = net work in kJ because the 24% efficiency offsets the 4.184 conversion rate almost exactly. At least this is true on a bike. Add the metabolic Calories for BMR and you'll be in the right ballpark.
