What is different about the runner's heart?

"If you run too much, it will kill you!" We have all seen the title of such awkward articles. This article tells you the truth behind this amnesty.

There is no doubt that whether it is running or any other routine endurance exercise will change your heart.

After all, the heart is a human body composed of muscles. Like all other muscles, it adapts itself to exercise intensity. For nearly a century, people have been arguing whether these changes are good or bad, but the most recent view is that even in the worst case, the most significant changes are harmless. Athlete's heart becomes bigger? That just means that the heart muscle is stronger, and the larger ventricle can deliver blood to the extremities, but it does not mean heart failure. Is the heart rate low when you are quiet? This is not an arrhythmia (irregular or abnormal heart rhythm) that occurs in non-running people, but it means that each contraction of the atria can deliver enough blood through the blood vessels, so the heart does not need to beat so frequently Now.

In recent decades, most discussions about running and heart risks have been about sudden deaths in marathons or other endurance events. These events have received very high attention and they can always be on the newspaper. In 1977, Paul Thompson participated in the 12km long distance race in San Francisco Baywalk. Paul is a cardiologist and doctor of medicine. His marathon's best result is 2 hours and 28 minutes. During that match, a sudden death occurred. This tragedy made Thompson interested in related research. Now he is working as a joint chief physician at the Hartford Center for Cardiovascular Care, and this center is the world's research runner. The heart is the most authoritative body that influences. In 1979, Thompson published a report mentioning that out of the 18 men and women runners who died during or immediately after running, 13 were suffering from heart disease. He and the co-author of the report said: "Even if your physical fitness is very good, it does not ensure that you can avoid the tragedy of sudden death."

In the 1970s, the trend of running for all the people was not so prevalent, so sudden deaths caused by running were rare. In 1975, the number of runners who completed the marathon race in the United States was 16,233; in 2015, 40 years later, this number has exceeded 500,000. Therefore, the sudden death of a marathon also evolved from an alarming accident to an event that must occur every year. Massachusetts General Hospital has a team that studies cardiovascular function and is led by Aaron Baggish, MD. In a report published by the team, there were 59 cardiac arrests in the US half-horse and all-horse events between 2000 and 2010, of which 42 were killed. So far, these examples have still drawn attention and are regarded as evidence by those who say that jogging is a dangerous sport. But the reality is that among those events, those who are below the age of 40 are usually due to previously undiagnosed hereditary cardiac abnormalities such as hypertrophic cardiomyopathy (the myocardium becomes very thick and hinders blood supply). If older runners die suddenly, they usually have had a heart attack before. Sometimes we cannot find a clear explanation. But no matter what the reason is, the heart's system is in a state of chaos, causing arrhythmia—that is, ventricular fibrillation that causes the heart to stop supplying blood.

If these are the entire truth, then the idea of ​​"opposed to running" can be easily refuted. Yes, a strong exercise (whether running, squatting, or sex) will temporarily increase the risk of your sudden cardiac arrest. But daily regular exercise has a huge impact on other factors that cause heart disease risk such as high blood pressure, obesity, or cholesterol levels, allowing you to work for the remaining 23 hours (assuming you have 1 hour of regular exercise every day) It is well protected. From this point of view, the benefits far outweigh the risks during the campaign.

However, this is not comprehensive. Regarding this issue, the latest discussion is no longer focused on sudden death, but whether running for many months or months will cause the heart and blood vessels to wear out faster.

According to this theory, every time you participate in a marathon, your heart will break through a limit, and in the long run, the active beating of the heart muscle will cause fibrosis. Fibrosis, like other losses caused over the years, may trigger atrial fibrillation, causing your normal heartbeat to become rapid, irregular beating. During running, the blood flowing through your coronary artery may accelerate the formation of arterial plaque and increase the risk of heart disease. (In turn, blood flow to the heart will also be blocked, causing cardiac arrest, your heart Will stop beating forever.

These above all show at least theoretically that compared to people of the same age who do not run at all, runners who perform long-term running will have worse health and shorter life expectancy. Today, 40 years have passed since the rise of the first running game. A large number of men and women runners have entered retirement time - most of the fun in their adult lives comes from running. Their death statistics have been made public, and it is scientists who have been debating how to correctly interpret the meaning behind these data. What the media reported in exaggeration was also discussed by some folk in the gym.

The 2012 American Sports Medicine Association was held in San Francisco. At the conference, participants were eager to discuss this topic. Dr. Duke-Zhe Li was an epidemiologist at the University of South Carolina at the time. A research team led by him presented a survey, including 50,000 patients who visited the Cooper Clinic in Texas from 1971 to 2001. Of these, 14,000 of them have the habit of running. The good news is that since their first medical visit, runners have had a 19% lower mortality rate than non-runners. The bad news is that these good results are basically those runners who run within 32 kilometers per week. For runners who run more, their relevant data is not much worse than the non-runners.

In the same week, Kansas City cardiologist, MD James Oakefe, and several of his colleagues published an article in the Journal of the Mayo Clinic, summarizing the excess heartache that may lead to the heart. Disadvantages: fibrosis, calcified arteries, and arrhythmias. Oake's article explains potential risks, and Lee's conference speech provides examples. The combination of them is a powerful combination. At that time, all news agencies around the world were interested in this story and immediately triggered a disturbance on social media. Some people worry that others are gloating (and indeed). The heartbeat of the gloaters may be: Those self-righteous, annoying runners think they are healthy? Haha, I can watch them ugly.

In the second half of 2012, Oak Fee and Karl Ravi jointly published an article in the journal Heart, summarizing the results of various surveys and claiming that the amount of time each day for strenuous exercise should be controlled within 30 to 50 minutes. Dr. Carl, MD, is a cardiologist in New Orleans. He previously co-published papers with Lee and Oak Feet. They wrote: "On the contrary, running too fast or running too much and for many years will speed up your arrival at the end of life." Of course, this story was also hyped by journalists and they made another round Warning. In the next few years, this model is still changing: between 2012 and 2015, Oake alone or in collaboration with people published more than 12 academic papers, all about the risk of excessive endurance sports, most of the The form of publication is comment, review of past findings, letter from the reader, and he also speaks at Tedx Talk with a click-through rate of more than 400,000. After repeated repetitions, people have already felt very kind about such titles. These assumptions have gradually become more and more like the facts.

The actual situation is that the dispute still exists. The next attempt to catch people’s attention was also about the risks of running overdose. It was initiated by a research group in Copenhagen, but the sample they used to draw conclusions was just two deaths in a group of strenuous runners—from statistics. It is academically unacceptable, and it has attracted many criticisms from other researchers. However, Lee's data at the 2012 American Association of Sports Medicine, although often cited as evidence of "a fatal risk from running," has not passed "peer review," rules within the academic industry, and must be made by third parties. Assessing) has not been published in any academic journal. In 2013, Dr. Thomas Weber pointed out a superficial flaw in Lee's statistical report as a response to the writings of Oak Fee and Ravi: Researchers adjusted the data appropriately to reduce The respondents differed in BMI, blood pressure, and cholesterol levels, and these were just some aspects of running that could reduce risk. Thomas Weber, a cardiologist at the Icahn School of Medicine in Mount Sinai, New York, wrote: “Simply put, that article was, at most, from all available data, selected the part that could support their views. data."

Weber's comments highlight one of the biggest challenges in public health research: There are significant differences in behavior and physical characteristics among different groups of people. How do you compare them?

For example, among the patients surveyed at the Cooper Clinic, the ones who ran the most often were older than those who had fewer runs. Many of them smoked in the past and included women with a history of family heart disease. Each of these factors will affect the lifespan of a person in their own way, so it is impossible to directly compare the two people. However, epidemiologists have used a “statistical adjustment method” technique to correct these differences, allowing them to compare groups of the same age and smoking history.

But there are also times when this method is not working. Sometimes, the difference between groups is exactly what you are trying to study. If you compare the mortality rate of smokers and non-smokers, you will find that smokers are more likely to have lung cancer. But you can't adopt a "statistical adjustment" method to make the chances of lung cancer equal in both groups because smoking causes lung cancer and thus increases mortality. The difference in lung cancer rates between smokers and non-smokers must not be eliminated because this is the key. Weber also pointed out similar problems in the Cooper clinic analysis report. Running is considered to lower BMI, blood pressure, and cholesterol levels, which in turn can reduce the risk of heart disease. Researchers use a balanced set of parameters to show that: If you ignore the health benefits of running, running does not benefit health.

In 2014, Li and his colleagues finally published the data of the Cooper Clinic patients on the Journal of the American College of Cardiology (by rule, after a “peer review”), which was his first time in ACSM. Two years after the conference was preached. In the "peer review" version of this report, the data did not use the "statistical adjustment" of this controversial technology, so the results are very different. The authors did not warn of the risk of running more than 20 miles (32 kilometers) a week, but emphasized that a small amount of running — 5 to 10 minutes a day — plays a significant role in reducing the risk of death from heart disease. . The revised version states that if the running volume exceeds this range, it will not bring more benefits, but it will not bring any bad results.

This time, the media's reaction was quite peaceful. Ravi is also one of the co-authors of this paper. He said: “The press loves stories like sports are harmful to health, but we just want to emphasize that even a small amount of exercise is beneficial.” Of course, the debate is far from over. The portion of people in the study population that ran the most, running only 176 minutes a week, even with such a relatively modest amount of running data, the data still shows this possible existence - the risk of heart attack is much greater Higher than non-running groups.

This year's American Sports Medicine Association was held in Boston. Coincidentally, the first day of the conference was the Global Running Day. At the conference center, all the heavyweights have come and participated in a special seminar. The theme is: "The best amount of running for health reasons: running a lot, is it good or bad?" Mentioned by Lee, Carl Ravi, Paul Thompson, and Paul T. Williams, a biostatistician at the Lawrence Berkeley National Laboratory in California, who led a nationwide The runners and walkers health survey has investigated and tracked 156,000 men and women since its inception in the early 1990s.

The debate on the epidemic will begin between Lee and Williams. Lee was originally a bodybuilder in South Korea. He was very good-natured. He is now an assistant professor at Iowa State University. Four years ago, Li emphasized the role of health and longevity through short-term strenuous exercise - 5 to 10 minutes of exercise per day, which is less than the usual recommended standard of at least 75 minutes a week. His 2014 paper classified patients from the Cooper Clinic into five groups based on the amount of weekly exercise. In the debate, he highlighted the group of people who had the most weekly runs and subdivided them into three groups. As the volume of running increases, the risk of heart disease may rise, but there is no obvious data to prove that the risk has indeed increased. Li said: "This does not prove that running too much will have a bad effect. However, running too much may not be very good."

On the other hand, Williams contends that, in at least some areas, the large amount of exercise is positive. Many of the 156,000 samples he traced were recruited from US runners-up magazine Runner World magazine. The accumulated annual amount of running or walking amounted to 156 million miles (about 250 million kilometers), giving him sufficient Data can be excavated. Over the past few years, he has published 65 studies that describe the effects of running on various conditions including diabetes, stroke, cataracts, Alzheimer's disease, kidney cancer, and breast cancer. In almost every case, running can work, and the more you run, the better. For example, if a man runs at least 40 miles (64 kilometers) a week, he will have a 26% lower risk of coronary heart disease than those who are 13 miles (20 kilometers) on a weekly basis. Why is there such a noticeable difference between Williams' investigation and Li's investigation? Throughout the entire discussion session, Williams face was a diplomatic, quiet expression, but in the Q & A session, when he was asked this question, his face showed a faint smile: "Our sample is 156,000 people, more than their number. So I believe our data.” These epidemiological data allow most runners to feel at ease, but it does not tell us about the top of the data range – for some people, 40 miles (64 kilometers) per week is just warming up. For these people, the best data we have comes from the changes they have made in the heart after some decades of running or some potential warning signs. In the respective speeches of the conference, Ravi and Thompson gave their views as experts in cardiology about the changes in the heart of these people.

[How to refute? ]

The next time someone tells you:

"Isn't it not good for the heart to run?"

You can answer him like this:

“In fact, compared to people who don’t run, runners of the same age are 45% less likely to die from heart-related diseases. Indeed, people are still talking about how much running volume can bring you the greatest benefit. It may not be that The more you run, the better. But what is certain is that, for heart health, people who are not running are certainly not as good as those who run. The same is true for large runs."

The most well-documented risk is atrial fibrillation, which is the most common form of irregular or abnormal heartbeat (ie, irregular heartbeat). Atrial fibrillation is always associated with long years of movement in many studies. Thompson said that much of this is due to an increase in the left atrium, where blood is stored after returning from the lungs. This situation, if combined with other factors such as high blood pressure or diabetes, increases the risk of stroke, but it is more like a trouble than an impending threat. Not everyone agrees that "running is a high-risk activity." According to Williams, for example, people who run 39 miles (62 kilometers) or more per week have more irregular heartbeats than any other group. To be low, but Thompson and many others agree with this view.

Another serious consideration is that excessive exercise may lead to atherosclerosis, because calcium-rich plaques deposit in the arteries leading to the heart. This is also the disease diagnosed by the 1968 Boston Marathon champion Amby Burfoot (P102 "I love running"). As a result, the arteries narrow and become stiff, gradually reducing the ability to deliver blood to the heart - or a plaque suddenly ruptures, causing more severe blockages that lead to heart disease. One possibility is that, during exercise, the rapid blood flow through the arteries accelerates the formation of plaque, or movement alters the level of body hormones associated with the plaque. Another possibility is that those who choose to run are different in other respects, as Ravi said: "They may have a more extreme personality, so they are usually stressed and sleepless." We are also not clear. Whether the plaques in the arteries of marathon runners have the same risk as those in the non-running crowds. Thompson said that too much or too much plaque is bad news, but the thicker plaque can actually reduce the risk of heart disease. In addition, there is a growing body of evidence that the plaques in marathon runners are thicker and more stable, making them less likely to burst or block blood vessels. For example, data released by a British researcher at a conference last year showed that long-term runners and cyclists who selected 169 individuals as a sample, each of them adhered to exercise for 31 years, and averaged 7.7 hours of exercise per week if They run 35 miles (56 kilometers) or more a week and their arterial calcification levels increase. However, more than 70% of the plaques found in male athletes are thick and stable, whereas in non-athlete surveys, this plaque only accounts for 30%. Cardiologist Ahmed Merghani, who led the investigation, said: "For me, the process and shape of plaque formation is far greater than whether there is atherosclerosis. important."

Perhaps the most controversial topic is fibrosis and scar tissue, which accumulates in the heart after years of use and can also cause other problems, such as ventricular fibrillation. In 2011, British researchers examined the heart of 12 ultra-high athletes. These people have been training for an average of 43 years. Each person has completed an average of 178 marathons, 65 super marathons and 4 triathlons. Half of them showed fibrosis - "This is so universal and unexpected." Instead, a German survey earlier this year also selected 33 athletes with an average age of 45, including former Olympic athletes and a marathon champion. Ironman won several championships, but no evidence of fibrosis was found on them. Thompson's point of view is: This phenomenon is likely to exist, but the probability of occurrence is very small.

After each speech at the ACSM conference, the speakers were surrounded by eager questioners. Many people's expressions looked "lean and hungry" but they had already betrayed their personal interest in the subject. Is there a different risk between men and women? Li replied that according to his data, the benefits and risks of running have almost no difference for men and women, but there is a trend that women can get more health benefits through running. A dark-haired, slender lady near Thompson began asking him some technical questions. Then she was closer to him, whispered, and said: "There is still a private question. Do you still have patient appointments?"

See here, if you are like me, then you may have been completely confused. It seems that the heart is actually different for those who have long insisted on running, but the consequences have not yet been clarified.

The best way to get an answer is to conduct a medical experiment where each person is randomly assigned a weekly run and then insists on running for decades. Ravi said: "This is impossible.

You can stick for 12 weeks, but it's impossible to stick to it for a long time. "So, we can only make judgments using existing imperfect data.

In addition, even if we have perfect information, we still have to throw dice - just as we make many decisions every day. If you run at least 40 miles (64 kilometers) per week, you can extend 99% of your life to 2 years, but the other 1% will shorten your lifespan by 10 years. What should you do? Will you continue? If this ratio is 99.9% and 0.1%, what would you do? Similar decisions are uncomfortable, so we will not consider making decisions at some point - for example, whether we want to eat an antibiotic, or whether to go out in a good weather. This is why Thompson made such a summary of the results of this discussion: “The knowledge level is very interesting and clinically worth knowing, but it is not worth worrying about.”

If we can predict in advance that who belongs to the 0.1% of people who have a vulnerable heart, this calculus topic becomes different. We know that rare heart conditions, such as arrhythmogenic right ventricular cardiomyopathy, are associated with certain genetic defects. Those with congenital defects are more likely to suffer from excessive exercise. Perhaps the same is true for fibrosis and atrial fibrillation: Exercise increases your risk, but only on the basis of your own genetic deficiencies. Thompson mentioned the future of genetic testing and said: "I think this is a potential game." This does not mean that people with genetic defects can not run, but they will understand their own risks, maybe they can Instead of forcing yourself to challenge the 100-mile race, you can achieve a sense of accomplishment by running 10 kilometers.

At the end of the conference, I was very satisfied with my running habits. Today, I have a 2-year-old child and a newborn baby in my family. I can run 30 miles (48 kilometers) a week and my running is usually limited to 5 kilometers or 10 kilometers. But in the future, I still hope that I can try some cross-country or mountain super marathons and inspire my limits in another way. In addition, this debate will remind me not to take my advantage for granted – be aware that my arteries may be blocked and my heart beat may become a mess. Whether running can increase or decrease the risk of various heart diseases, understanding these risks can help me to see those warning signs.

Now even Ravi hates to exhort people to give up running. After he finished his speech, when we met, he said to me: "The current data is not sufficient, there is no need to publicize 'run no more than 30 miles per week (48 kilometers)'". However, he does hope that his patients can understand that even if they run for 5 to 10 minutes a day, they can get the most health benefits. So, in fact, they do not need to force themselves to become marathon runners for health. If you are too strict, the advantages of running may be reduced. If they are older and there are other potential risks of heart disease, he may suggest that they perform an exercise stress test and coronary artery calcification test and take statins to control cholesterol levels. He said: "If someone runs 40 miles (64 kilometers) a week, I will ask them why they run so much. If they just like it for the sport, I would never use a theory to scare them. ."

This kind of gentle answer really surprised me: After listening to those deaf news headlines, I once thought that what I was going to face was a “guardian” who was determined to oppose excessive running. But Ravi is not such a person at all. Usually, on most days, he will run for 45 minutes at lunchtime and run 30 miles (48 kilometers) or more a week. In the past he ran more. He still participates, although his speed is not as good as he used to be, but he still cares about his pace. Like most runners, once he walked out of the door and ran in the sunshine in Louisiana, he wouldn't consider his own heart problems. He said: "Running makes me relieve stress, my mood gets better, and I can eat more food. But the most important thing is that I enjoy the process of running."