When you know your resting heart rate then you also know under how much load your heart is during baseline activity. That is - during times when there is no special load exerted upon it which would require for it to run faster.
If your resting heart rate would be lower for example, then you would probably be able to conclude that the heart needs to beat less times in a minute for it to have the same effect as of the person with a much higher resting heart rate.