Long-distance running can easily lead to sudden death? The truth is...

Rumor: "Long-distance running can lead to sudden death!"

Sudden death incidents during marathon running occasionally occur, so there are many rumors circulating online that "long-distance running can lead to sudden death", which makes many people wonder how running can become a high-risk behavior? Should we run for fitness?

Rumor analysis: This statement is not rigorous.

Sudden death is mostly caused by existing diseases among the exercise participants themselves. It is incorrect to simply say that “exercise causes sudden death”.

In recent years, with the popularization of the concept of national fitness, many people have extended their hard work at work to fitness. Long-distance running, marathons, cross-country and other forms of sports are deeply loved by middle-aged and young people. No matter how tired they are at work, many people will insist on completing exercise plans such as morning running and night running. However, every year, "sudden death during running" incidents occur from time to time, so many netizens have discussed it, believing that "running is harmful to the body" and "long-distance running can cause sudden death." So, is running really a high-risk sport that can cause sudden death?

Copyright images in the gallery. Reprinting and using them may lead to copyright disputes.

Let me give you the answer first: The statement that “long-distance running can cause sudden death” is not accurate.

Long-distance running, marathon and other sports are long-distance endurance events that can improve the human body's cardiopulmonary function, enhance leg muscle strength and lower limb bone density to a certain extent, and can also improve immunity and prevent cardiovascular disease.

The reason why sudden death occurs during long-distance running, marathon and other sports is actually mostly caused by the underlying diseases of the participants themselves, such as congenital heart disease, myocarditis and heart failure, which may induce sudden cardiac death, or cerebrovascular malformations, cerebral aneurysms, cerebral arteriosclerosis and other diseases that may induce sudden brain death. In addition, if the runner's training method is unreasonable, it will also increase the risk of sports injuries.

Studies have shown that under normal circumstances, the probability of sudden death among runners is very low. In other words, the root cause of sudden death during exercise is not exercise, but exercise is only a trigger. Therefore, it is not correct to say that "exercise/long-distance running causes sudden death."

Three things to note when exercising scientifically

1. Understand the intensity of exercise you can tolerate

In order to confirm your current physical ability and rule out inappropriate exercise, it is recommended to do a "12-minute run" test. The "12-minute run" can be used to test cardiopulmonary function and aerobic endurance, and is widely used in fitness testing and training for adults in schools, the military, sports teams and other institutions.

Test method: Run the maximum distance as hard as you can in 12 minutes. You can run, walk briskly, or alternate between running and walking, but try to maintain the fastest speed.

Heart rate: After running, your heart rate should be less than 180 minus your age.

Distance: Young people should be at least 2000 meters, and the elderly should be at least 1500 meters.

Based on the actual distance D, the most suitable exercise metabolic equivalent can be calculated.

MET = (D-504.9) * 3.5/44.73

If you run 2000 meters in 12 minutes, then the MET formula should be (2000-504.9)*3.5/44.73, and the result is 9.53. (Note: "12-minute run" is a non-laboratory method to estimate an individual's maximum oxygen uptake. It is not accurate enough and is used when there are no laboratory testing conditions.)

MET metabolic equivalents refer to how many times the metabolic level of a certain type of exercise is equivalent to that of resting. For example, we define the MET for complete bed rest as 1, and the MET for jogging as 8, which means that jogging is equivalent to 8 times the metabolic level of resting state.

Spring, summer, autumn and winter, with the change of seasons and the ups and downs of the external environment and personal state, we should regularly do a "12-minute run" test on ourselves, so that we can more objectively control our own abilities and not blindly show off our strength.

It should be noted that patients with confirmed or suspected cardiovascular, pulmonary or metabolic diseases or kidney diseases must obtain a doctor's permission before participating in a high-intensity exercise program.

2. Replenish salt-containing and low-sugar liquids in a timely and appropriate manner, and avoid drinking ice water

Imagine the human body as a hybrid car. The glucose in the blood is gasoline, and oxygen is electricity. When there is enough glucose and oxygen, the muscle "motor" will work quickly, allowing us to run and jump. The used glucose "gasoline" turns into lactic acid, which makes the muscles sore and swollen. The oxygen turns into carbon dioxide and is exhaled from the body. At the same time, a large amount of water is produced. The process of excreting water from the body is just like the heat dissipation principle of a car's "radiator".

When we are short of oxygen, our heart rate will speed up; when there is insufficient glucose, the body will start to consume fat for energy, but this process is too slow and is far from meeting the energy needs of exercise. Therefore, we need to rely on sugar (the sugar here refers to carbohydrates) to provide energy during exercise. Most of the energy during short-term, high-intensity exercise is supplied by sugar oxidation, and long-term, low-intensity exercise will also first use sugar oxidation for energy. Therefore, during high-intensity exercise, you can supplement with some sugary drinks to supply energy to the body.

In addition, drinking more water during exercise will make you thirstier, so a good choice is to replenish electrolyte drinks in time.

It is easy to sweat during exercise. In addition to the sweat smell, there will be white sweat stains on clothes. These are the crystals of electrolytes lost from the body. As trace minerals in the body, electrolytes will become positively or negatively charged ions once dissolved in water. These charged minerals are responsible for balancing the body's water, maintaining the body's acid-base balance, delivering nutrients to cells, excreting waste from cells, and regulating nerve, muscle, heart and brain functions.

Sweating and having a dry mouth during exercise are usually signs of dehydration. Drinking a lot of water at this time will not only fail to quench your thirst, but will also increase sweating and make your dehydration more obvious. The main electrolytes in sweat are sodium and chloride ions, as well as small amounts of potassium and calcium. Whether before, during or after exercise, sodium helps maintain fluid balance, while potassium helps regulate heartbeat and maintain muscle contraction during exercise. Therefore, replenishing the various electrolytes needed by the body in a timely manner during exercise is the key to quenching thirst and body thirst.

It is recommended to take a break and replenish water every 15 minutes to half an hour of exercise. Once you experience heavy sweating, increased heart rate, muscle cramps and dry lips, you must also replenish electrolytes.

In addition, the vagus nerve is in an activated state after exercise, which will gradually reduce heart rate and blood pressure. At this time, you should be careful to avoid drinking a lot of ice water, because the stimulation of ice water to the digestive tract may excessively enhance the tension of the vagus nerve, causing blood pressure and heart rate to drop too quickly, thereby inducing shock, myocardial ischemia or other underlying cardiovascular diseases.

3. Warm up and cool down

Many people know that you need to warm up before exercise. It should be noted that the "cool down" after exercise is also very important. Many people sometimes sit on the ground or collapse directly after exercise because they are too tired, and do not pay attention to finishing and stretching after exercise. However, stretching after exercise is actually a part of exercise and is not dispensable.

First, stretching exercises themselves can lower blood pressure, improve arterial stiffness, slow down heart rate, lower blood pressure, and gradually bring people into a state of physical and mental relaxation through physical and biochemical pathways such as mechanical traction on blood vessels and muscles and inducing the vascular endothelium to release vasodilator factors.

Second, muscles tend to remain stiff and tense after exercise, and muscle fibers may also suffer from some microstructural damage, leading to delayed onset muscle soreness (DOMS). Timely stretching can relieve muscle tension and help restore muscle fibers to their original alignment, reduce muscle soreness symptoms after exercise, eliminate muscle fatigue, and accelerate muscle recovery.

Third, during exercise, a large amount of blood is distributed in the blood vessels of peripheral skeletal muscles. When the intense exercise is over, low-intensity finishing exercises can promote the return of blood to the cardiovascular system and other internal organs, helping the body's systems return to normal.

Copyright images in the gallery. Reprinting and using them may lead to copyright disputes.

Summarize

The statements that "exercise causes sudden death" and "long-distance running leads to sudden death" are not accurate. The root cause of sudden death during exercise is not exercise, but the disease that the athlete himself has. Exercise is only a trigger.

In daily life, scientific and safe exercise requires first understanding the intensity of exercise you can withstand; secondly, timely and appropriate replenishment of low-sugar liquids containing "salt" and avoid guzzling ice water; in addition, pay attention to warming up before exercise and "cooling down" in time after exercise.

Looking in the mirror of rumors

The reason why such rumors can spread is that people fail to see the essence of the phenomenon. Due to the lack of relevant professional knowledge, many people will make simple and crude attributions to the results of the incident. In addition, since it is related to health and life safety, many people will have the mentality of "it is better to believe it than not to believe it". In fact, it is a good thing that everyone pays close attention to their health and life safety. When encountering such rumors, I hope everyone can seek verification or consult professionals to avoid being misled.

References

[1] Cermak NM, van Loon LJ. The use of carbohydrates during exercise as an ergogenic aid. Sports Medicine. 2013;43(11):1139–1155.

[2]Jeukendrup AE. Carbohydrate and exercise performance: the role of multiple transportable carbohydrates. Current Opinion in Clinical Nutrition and Metabolic Care. 2010;13(4):452–457.

[3]Massicotte D, Pe ́ronnet F, Adopo E, Brisson GR, Hillaire Marcel C. Effect of metabolic rate on the oxidation of ingested glucose and fructose during exercise. Int J Sports Med 1994;15:177.

[4]Shirreffs SM, Sawka MN. Fluid and electrolyte needs for training, competition, and recovery. Journal of Sports Sciences. 2011; 29(Suppl 1):S39–46.

[5]Kenefick RW, Cheuvront SN. Hydration for recreational sport and physical activity. Nutrition Reviews. 2012;70(Suppl 2):S137–142.

[6]Goulet ED. Dehydration and endurance performance in competitive athletes. Nutrition Reviews. 2012;70(Suppl 2):S132–136.

[7]Jeukendrup A, Carter J, Maughan RJ. Competition fluid and fuel. In: Burke L, Deakin V, eds. Clinical Sports Nutrition. 5th ed. North Ryde NSW, Australia: McGraw-Hill Australia Pty Ltd; 2015:377–419.

[8]Bergeron MF. Exertional heat cramps: recovery and return to play. Journal of Sport Rehabilitation. 2007;16(3):190–196.

Author: Sun Yueli, Associate Researcher and Associate Chief Physician at the Institute of Spine Diseases, Longhua Hospital

Review丨Ma Yong, Professor of Wuhan Institute of Physical Education