Calorie accounting

What is your Resting Metabolic Rate (RMR - see it for example at connect.garmin.com/.../last_seven_days as the value of the blue column), and how the HR graph for the run looks like? What was the duration of that run? Also what value is set as Activity Class in User Settings?

Hi, I checked my Heart rate and the past week was 109 bpm on average. Two weeks average was 108 bpm. I did 2 runs today, both the same distance and close effort. The first was 15.2km at 7:06 pace, the second was 15.12 at 7:05 pace. The first run used 586 calories and the second was 812 calories according to my Garmin watch. I always thought that a km was about 80 calories or 120 calories per mile. Garmin is giving me less than half of that. 

Sorry, my resting heart rate is about 60 bpm or less.

I asked about the Resting Metabolic Rate, not the Resting HR, but never mind. The Calories burned during an activity are calculated from the immediate HR (and from the HR Variability), the distance does not play any role (at least as long as the HR Monitor is on). However, there are many factors that influence the calculation - the gender, age, weight, heigth, and also the Activity Class. Make sure that all the parameters (including the Activity Class) are correctly set.

Then also verify that the HRM delivers reliable HR data. If not, adjust the fit and position, or use a chest belt HRM.

I didn't realize RMR was different than RHR

RMR = the rate of Calories being burned during rest (similar to the BMR - basal metabolic rate)

RHR = heart rate at rest