During a cycling workout is the maximal heart rate the same as when running?
An individual’s maximal heart rate doesn’t change. He or she may be working at different percentages of their heart rate but that doesn’t have an effect on one’s heart rate maximum.
To know how many calories are burned during a bout of exercise, one would need to know the metabolic equivalent of the activity the individual is engaged in. For the purpose of your question one would need to know the metabolic equivalent for cycling and running and also know at what intensities those activities are being performed.
Lastly, there is no correlation between the number of times the heart beats and how many calories are burned.
I hope this helps.