The number of heartbeats in children is related to age, activity, mood, fever and other factors, and needs to be analyzed on a case-by-case basis. In general, the normal heart rate for newborns is around 120-140 beats per minute, for children under 1 year old it is around 110-130 beats per minute, for children 2-3 years old it is around 100-120 beats per minute, and for children 4-12 years old it is mostly around 60-100 beats per minute. This shows that the younger the child, the faster the normal heart rate. The heart rate of children is usually less stable, such as after eating or strenuous activity, the heart rate will speed up accordingly; while in a quiet, sleeping state, the heart rate usually becomes slower. If a child’s heart rate is measured to be fast in a quiet state, or if a child has chest tightness, shortness of breath, or weakness in the arms and legs while the heart rate is accelerated, it is recommended to improve the electrocardiogram and myocardial enzyme profile in time to avoid delaying the disease.