I didn’t know this, but it seems to be true. Back when I started tracking my runs, I used a Garmin watch: Garmin does use HR to calculate energy expenditure.
I switched to RunKeeper about 6 years ago – eventually buying a new HRM to go with it.
I never bothered to check the algorithm.
DC Rainmaker is the ultimate source of nerdish fitness equipment advice for me. I didn’t know about it back then.
Shall amend notes.