First, welcome to the community. Echoing what Pete suggested, what questions do you have about heart rate? For example do you want to compare heart rates for individuals at different ages or sexes or with different underlying conditions? Do you want to determine if heart rate is stable for a particular individual? Do you want to understand what factors mat contribute to the variation in heart rate? Do you want to assess the measurement system? etc.
"All models are wrong, some are useful" G.E.P. Box