Is it normal that the heart beats 56 times?

The medical classification of heart rate is: whether male or female, the heart rate is 60~ 100 beats/min, which is normal; This is different from the actual population, and it is also common for some young people to have a heart rate below 60 beats/minute. People who have been engaged in heavy physical labor or strenuous exercise for a long time may have a healthy heart, and their heart rate may be lower than 40 beats/min, even with exceptions. After the death of a former British marathon champion, autopsy found that his heart was 30% heavier than normal, and his coronary artery was about 1 times thicker than normal. This kind of heart contraction is more powerful, and the output of each contraction doubles, which can meet the normal blood supply even if the heart rate is very low. The heart rate of a normal adult is about 75 beats per minute. The elderly over 60 years old should be alert when their heart rate is lower than 50~55 beats/min, and those whose heart rate exceeds 90 beats/min for a long time should also be alert. What is the normal heartbeat time of different age groups? The heart rate of the elderly is relatively slow, generally 55~78 beats/minute; The heart rate of newborn babies is about 1 10~ 150 beats/min. The heart rate of children around 2 years old is about 85~ 125 beats/min; The heart rate of 4-year-old children is about 65~ 105 beats/min; In a quiet state, the average adult's heart rate is about 70~80 beats/min, which is slightly faster for women. Not only that, the heartbeat speed is also regulated by vagus nerve and sympathetic nerve, even when people are in a state of anger, tension and excitement, the heartbeat will accelerate; When you are asleep or quiet, your heart will slow down. Although many people don't feel it, those who have done 24-hour ambulatory ECG monitoring must have a deep understanding. Is there a relationship between heart rate and life expectancy? Relevant data show that the total number of heartbeats of all mammals except humans is basically the same, about 800 million. Therefore, the slow heartbeat is closely related to the life span of animals. The tortoise's heartbeat is about 6 times per minute, so the tortoise's life can be as long as 200 years. Swallows have a heartbeat of 1200 times per minute, so their life span is extremely short. The heart of a mouse beats 900 times a minute, so its life span is about two years; The heartbeat of a cat is 240 beats per minute, so the average life span of a cat is 5-6 years. Although such figures cannot prove the conclusion that the slower the heart rate, the longer the life expectancy, but some studies have found some links between heart rate and cardiovascular disease. Norwegian researchers studied 30,000 people for 10 years. The resting heart rate of 30 thousand people was tested twice. It was found that if the heart rate was lower than 70 beats/min ten years ago, the risk of heart disease death would double if the heart rate increased to 85 beats/min ten years later. People whose heart rate was between 70 and 85 beats per minute ten years ago will have a heart rate of more than 85 beats per minute ten years later, and the probability of death will increase by 80%. But if the resting heart rate decreases, the effect is just the opposite. People whose heart rate was 70-85 beats/min ten years ago, if it drops below 70 beats/min ten years later, the probability of dying of heart disease can be reduced by 40%. The power of a small heart is amazing. It takes eight hours to lift a car. Everyone's heart size is slightly different. Generally speaking, a person's heart is the size of his fist. That's it. The power of a small heart is amazing. In a quiet state, the bleeding amount of 1 min is about 4500ml, which translates into a body weight of about 4.5 kg, so the bleeding amount of one day and night is about 6400 kg. Even in sleep, the heart does work within 8 hours, which is equivalent to lifting a car to more than 2 meters. If the heart lifts itself with this force, it is enough to lift more than 20 kilometers. What is the secret of the law of the heart's never-ending beating? The heart is like a tireless perpetual motion machine, and life keeps beating. However, the heart can beat regularly, which is not an instruction from the brain. Heartbeat is that the heart itself has self-discipline cells to control the beating of the whole heart. This regular beating depends on the blood supply. As long as there is enough nutrition and oxygen, myocardial cells can beat automatically. But this regular beating of myocardial cells is also under the command of the "commander-in-chief", rather than blindly beating. If we are divorced from the unified command of the Commander-in-Chief, there will be problems, that is, various clinical arrhythmias. This "commander in chief" is called "sinus node", and the usual "sinus rhythm" is emitted by sinus node, which is normal. The normal conduction pathway is: sinoatrial node → internodal bundle → atrioventricular node → atrioventricular bundle → left and right bundle branches → myocardial conduction fibers. Heart is really tired, will it never move? The human body is a very magical institution, ready to combine work and rest at any time in the process of growth and development. The law of cardiac contraction and relaxation is a set of work and rest processes. Taking 75 beats per minute as an example, a cardiac cycle is 0.8 seconds, and the contraction time of atrium and ventricle is 0. 1 second and 0.3 seconds respectively. But the relaxation time is 0.7 seconds and 0.5 seconds respectively. Atrium and ventricle alternately contract and rest, and relax and rest while contracting for a certain period of time. Can the heart beat without the body? In the movie "The Legend of raiders of the lost ark's Magic Palace", there is a scene: the human heart is still beating after being pulled out alive, and it has been beating for a long time. After watching this movie, someone can't help asking: "Can the heart still beat after leaving the human body?" It's actually true. If you leave the human heart, you can continue to beat as long as you give enough oxygen to the myocardium. This is because the heart does not need the stimulation of other nerves, and the muscles of the heart will generate current to stimulate the contraction of the myocardium and keep beating. The heart can be kept away from the body for up to 8 hours. Before heart transplantation, the preservation of the heart is solved with ice, but the longest limit of this method is 3~4 hours. However, a year ago, foreign media reported that a new technology solved the problem of heart preservation. This is an organ survival system (the donor's heart is implanted in a box), which simulates the human environment and injects oxygenated blood into the heart, so that the heart can be like the body. This technology extends the preservation time of organs in vitro by 8 hours, which means that the heart can be sent to further places, and more people who need heart transplantation will benefit.