With the abolition of the approval system for marathons by the China Athletics Association, marathons in China have shown explosive growth for nearly five consecutive years, and the trend continues, constantly setting off the climax of national fitness. However, with the increasing number of marathon events and participants, the tragedy of sudden death in the marathon has occurred from time to time, and the trend is on the rise. To our public participation also sounded the alarm, the prevention of sudden death in the marathon is particularly important, only to clarify the causes of sudden death in sports, in order to effectively prevent and minimize the occurrence of tragedy. Today, we will analyze what is the cause of sudden death in the marathon, how to prevent? First, what is sudden death in a marathon? According to the definition of sudden death in the medical field and the occurrence of sudden death in sports, sudden death in marathon can be defined as a non-traumatic accidental death that occurs during or within 24 hours after sports, which is characterized by sudden onset, acute course, heavy condition, and difficult to save. Second, the occurrence of sudden marathon death in recent years: domestic studies with statistical data show that 19 sudden marathon deaths occurred between 2004 and 2017, of which 18 were male and 1 was female. between 19-35 years old, accounting for 79% of all sudden deaths. Through a comprehensive analysis of statistics, the trend of marathon death is: 1, young and strong men have better physical fitness, usually hobby sports; 2, like to catch up with fashion, there is not much understanding of the marathon; 3, usually lack of relevant training, think that the half marathon is relatively easier, do not need training with perseverance can persevere. And it is due to the lack of sufficient knowledge of their own health and the lack of awareness of the dangers of the project, resulting in excessive perseverance before the end, blind sprint, which eventually led to the occurrence of sudden death. Third, what are the causes of sudden death in the marathon? 1, sudden cardiovascular death is the main cause of congenital coronary malformation, hypertrophic cardiomyopathy, idiopathic left ventricular hypertrophy, myocarditis and other cardiogenic diseases are the main causes of sudden death. In addition, cerebrovascular malformations, aneurysms and hypertension and other diseases of cerebral origin are also risk factors that induce sudden death from exercise. According to statistics, more than 90% of sudden athletic deaths are cardiogenic sudden deaths. 2, respiratory system diseases respiratory system diseases such as exercise asthma, pulmonary artery thrombosis and primary pulmonary hypertension can also be induced by exercise and aggravate the disease, if not timely detection and treatment, will cause sudden death. 3, exercise lack of science guidance usually lack of systematic training to participate in the marathon, or do not follow the training principles, blindly increase the amount of exercise and exercise intensity, may induce arrhythmias, myocardial ischemia and heart failure, resulting in sudden athletic death. 4, adverse external triggers Adverse external triggers mainly include tonsillitis, cholecystitis and other internal infections, adverse weather conditions, plateau hypoxia and inappropriate exercise periods, etc. If you exercise under these adverse conditions, may trigger sudden athletic death. Fourth, how to prevent sudden death in the marathon? 1.Strict physical examination to ensure good health Before participating in the marathon exercise, a comprehensive physical examination must be conducted in order to identify potential high-risk factors as early as possible. If the physical examination found to suffer from heart disease, lung disease, hypertension, hyperlipidemia, diabetes, or family history of heart disease, cerebrovascular accidents or sudden death, should avoid participating in long-distance running exercise, 2, exercise should be gradual, control the intensity of exercise gradual is the principle of long-distance running exercise must follow, do not compete or sudden whim, blindly increase the amount of exercise. At the same time, also to prevent “concentrated exercise”, that is, usually no time system exercise. Non-athlete exercise target heart rate should generally be controlled in the range of (170 – age) x 85% – 90%. But no matter what kind of exercise intensity, if the practitioner continues to appear chest tightness, shortness of breath, panic, headache, nausea and other conditions, should immediately reduce the intensity or stop practicing, otherwise accidents are very likely to occur. 3, avoid exercising in bad conditions If you have a cold or infection, do not exercise within two weeks, and then exercise after recovery; you should try to avoid exercising in cold, heat, hazy weather conditions; the morning is the high incidence of cardiovascular disease and susceptible period, so marathon running exercise should not be arranged in the morning, it is best to arrange between 3-4 pm, when the air quality is also relatively good. Finally concluded to everyone, because of the rapid onset of sudden sports death, the condition is dangerous, the success rate of rescue and treatment is low, so prevention should be the main focus. First of all, we should carefully consider and actively assess whether we are suitable for marathon sports; secondly, we should carry out cardiovascular and cerebral diseases or other serious diseases before the race; then actively, gradually, scientifically and reasonably train and adapt; finally, if you are uncomfortable when participating in the race, you must not force yourself, such as feeling dizzy, headache, difficulty in breathing, chest tightness and other symptoms, do not blindly insist or sprint, you should ask medical staff for help. This will be able to protect their own health, but also in the marathon race to feel the struggle and sports bring excitement and comfort.