Energy expenditure - watts into KJ vs kcal

Hello together,

I have been discussing the following question with my girlfriend for a while and we cannot agree on an answer. Possibly you can help us solve the question:

Assuming two identical riders both pushing 200 watts for an hour. This equates to approximately 720 KJ. To my knowledge the kj can be converted into kcals with the ratio of 1 to 1 (due to factors such as efficiency, etc.), hence the riders burning 720 kcal in this hour. However, how does heartrate factor in? If rider A is riding at only 70% and rider B at 90% of max heartrate, is rider B going to be burning more calories? If so, what is the reason and how can the total effect be approximated?

I look forward to an interesting discussion and insightful answers.



3 posts were merged into an existing topic: A question on Calories