Scientists have long found that small mammals can have a heart rate of hundreds of times per minute, such as rodents, rabbits, etc., their short life span of only 1-3 years, on the contrary, large mammals, such as large whales heart rate of only about 20 times per minute, its life span of up to 30-40 years, the life expectancy of the tortoise in Grappagos can be up to 177 years, its heart rate of only 6 times per minute, a total of about 560 million times a lifetime heartbeat. Surprisingly, further research by scientists confirmed that all mammals have basically the same number of heartbeats in their lifetime, about 730 million. Scientific studies have also demonstrated that each animal is different in size, but the ratio of heart weight to body weight is also roughly the same, at 0.5-0.6% of body weight. Although the exact reasons for the close correlation of these phenomena have not been fully elucidated, it is agreed that heart rate is determined by the energy metabolic demand of the organism, and observing the laws of biophysics, the exhaustion of energy of the organism, the end of life, heart rate is the external expression of the energy metabolism of the organism, and is a reliable, simple and repeatable indicator. Does the human life span also obey the above law? It has been found that human beings are very different from this, mainly human beings live much longer than animals under similar heart rate conditions, up to 70-80 years, mainly because of the development of science, medicine and health care and social progress, so that human life expectancy can be extended. The human heart rate is mainly managed by the sinus node cells of the heart, which we call sinus rhythm. Normal sinus rhythm is 60-100 beats per minute. The number of heartbeats in humans is obviously influenced by autonomic and humoral factors, such as the heart rate increases when a person is excited and automatically slows down when he or she is completely quiet. Scientific studies have shown that an adult with a resting heart rate of 70 beats per minute can live up to 80 years. The total number of heartbeats in a person’s life is about 2.5 billion to 3 billion, and if the resting heart rate is around 60, the life expectancy can be 93 years. Therefore, people with a slow resting heart rate have a longer life expectancy, while those with a resting heart rate greater than 80 beats have a shorter life expectancy. Numerous clinical studies have also demonstrated that people with a fast resting heart rate have a significantly increased risk of various cardiovascular diseases and a high mortality rate.