Childhood is divided into different age groups, and the number of heartbeats varies from age to age; the younger the age, the faster the heart rate, and the older the age, the closer it is to the adult level. In general, the heartbeat of a newborn is 120-140 times a minute; for a small baby less than one year old, it is 110-130 times a minute; for a toddler 1-3 years old, it is 100-120 times a minute; for a preschooler 4-7 years old, it is 80-100 times a minute; for a school-age child 8-14 years old, it is 70-90 times a minute. There are many factors affecting the jump, such as fever, exercise, crying, stress, and dehydration, which can increase the heart rate. During the nighttime sleep state, the vagal tone is increased and the heart rate is slower than during the day. Measurement of heart rate must exclude the influence of these distracting factors, and requires one minute of measurement in the baby’s awake, quiet and relaxed state as the baby’s actual heart rate.