What is the definition of a resting heart rate?

the number of times the heart beats while doing an aerobic activity after a period of rest

the number of times the heart beats in 1 minute when not active

the number of times the heart beats in relation to blood pressure

the number of times the heart beats in 1 minute while sleeping

The definition of a resting heart rate is the number of times the heart beats in 1 minute when not active.