In a normal human adult, your heart beat will on average be 60-100 beats per minute. However one thing about medicine is that we never treat the numbers but the patient, and there are people who's heart rates can be lower or higher.
Additionally children and infants to tend to have higher heart rates.
To be honest, clenching fists. it may feel like you’re doing something but in my opinion it isn’t. at the end of the day it only leaves your hand hurting.