I have an apple watch that regularly records my resting heart rate in the 50s. i am not an athlete, this seems low. i did have holter monitor/stress test/bloods recently & was normal. sometimes i get dizzy should i go back to dr?

If you feel dizzy with a low heart rate, you have to see your doctor back and see if there are other factors causing you to be dizzy. A resting heart rate of 50 is not unusual if you are on meds for your hypertension. If you feel dizzy, your BP may be low when symptoms arise.

Possible causes of mild resting bradycardia: 1) excellent physical condition even if not an athlete; 2) drug effects esp. older β-blockers; 3) a cardiac conduction abnormality but it seems that's been ruled out. If it's not #1, check out #2.