Was just coming to say that there's definitely a genetic component. Even in my more sedentary periods of life, my resting HR never really peaked above ~55 BPM. Playing tennis and going for regular runs with my husky puts my resting HR at 38-40bpm. My father who also runs and plays sports has a similar heart rate.
Just so we're clear on definitions, resting HR is your heart-rate AT REST (meaning sitting or lying down quietly), it's not necessarily your HR while you are sleeping which may be potentially lower.
Just so we're clear on definitions, resting HR is your heart-rate AT REST (meaning sitting or lying down quietly), it's not necessarily your HR while you are sleeping which may be potentially lower.