Whats the normal hart rate? what if its too fast?

60-130: Normal resting heart rate can be a wide range. In children they typically can have resting heart rates in the 100's and is normal especially in infants. In adults it is usually 60-90, lower for those who exercise very regularly. Above 100 in an adult can be normal with exercise but if it is above 120 at rest it could be a sign of an abnormal rhythm that can be checked by you doctor.