Some doctors tell me 60-100 is a normal heart rate; other doctors tell me 60-80 is a normal heart rate? 80+ is cause for concern. which is correct?

Normal: A 60-100 beats/min is a normal resting heart rate in adults.

Normal: The normal heart rate is defined as 60-100 bpm. Your individual heart rate will vary widely throughout the day in response to a multitude of factors. In general, a lower restring heart rate is indicative of a higher level of fitness, but that is not always the case. Hope this helps!