It’s lunch break, and the marathon registration page is open on your phone. Full name, date of birth, shirt size, blood type, emergency contact: you fill them all in without stopping. At the last box, your finger pauses: “I confirm that I am healthy enough to take part.” One tap and the paperwork is done.
Next to the phone is the blister pack of blood pressure pills you have taken every morning for two years now. Last month, in a 10 km race, at around the seventh kilometer your chest tightened as if someone were pressing down on it with their hand. You walked for a stretch, the tightness gradually eased, then you ran on to the finish and told no one.
That box is your own promise. The organizers do not examine you. For a middle-aged runner, it is the spot on the whole registration page most worth pausing over. The chest tightness in the middle of last month’s run needs a cardiologist to look at it first; choosing a distance can wait.
Chest tightness at the seventh kilometer
There are not many heart warning signs that call for a check-up before a race. The US internal medicine textbook CMDT (Current Medical Diagnosis and Treatment), the sports injury book by Joyce and Lewindon (2016) and the guidance of the American College of Sports Medicine (ACSM; Roberts and colleagues, 2021) all place the following in the group where you must stop running and have your heart checked:
- Chest pain or chest tightness during exertion;
- Unusual shortness of breath;
- Palpitations, or an unusually irregular heartbeat;
- Fainting in the middle of a run;
- A family member who died suddenly at an early age.
The tightness that day eased when you switched to walking, and that is where the trap lies. Runners tend to read this detail in a reassuring way: it must have been the heat, I probably didn’t warm up properly. The sources above do not set any condition on how long the pain must last before it is worth a check-up. In our view, one episode of chest pain during exertion, even if it went away by itself, is still a reason to have your heart checked, and the check-up should come before you register for your next race.
And if chest pain comes on in the middle of a race, stop running, alert the race medical team or call 115 (emergency), even if the finish is close.
Collapsing before or after the finish line
Of all the signs, fainting is the one that frightens the people around most. The same collapse can be harmless or very worrying, depending on when it happens.
Someone who faints just after crossing the finish line usually has something fairly harmless. Throughout hours of running, each time the lower leg muscles contract they squeeze blood from the legs back to the heart; doctors call this the muscle pump. Past the line, the runner stops dead, the muscle pump stops with them, blood pools in the legs, and less reaches the brain for a moment. Lay the person down with their legs raised and most come round; if they are fully alert and all discomfort has gone within 30 minutes, it is usually harmless (Joyce and Lewindon, 2016; Papadakis and colleagues, 2022; Roberts and colleagues, 2021).
Fainting while still running is different. The legs are still working and the muscle pump is still squeezing blood back, so the explanation above does not apply. The sources put this kind of fainting in the group that needs a heart check-up.
Whoever was with the runner can help the doctor a great deal with a few details: did they fall before or after the finish line, how long after lying down with their legs raised did they come round, and did they complain of chest pain when they came to. Someone who is confused and talking nonsense after a long race is a different matter again, and needs medical staff to measure their body temperature and blood sodium (the amount of sodium salt in the blood).
Stories told on the death anniversary
The last sign on the list is not inside your body. It lies in your family’s story. A family member’s sudden early death is a reason for a heart check-up, and your job is to know the story and tell the doctor all of it.
In many Vietnamese families, those who have passed away are only talked about on their death anniversary. After the incense has been lit and the memorial meal laid out, the aunts and uncles sit down and tell the stories: grandfather died suddenly out in the fields, the eldest uncle was sitting having a drink of water when he slumped over. To young people it sounds like old tales. Your family may have a story like that too: your father died suddenly years ago, while he was still going to work as usual, and the family rarely mentions it. For someone about to register for a marathon, that is part of your medical history. At the next death anniversary, ask a few more questions: who died suddenly, at what age, what were they doing at the time, did anyone say it was the heart.
Defibrillators along the course
Cardiac arrest in marathons and half marathons is rare. Kim and colleagues (2012, 2025) gathered race data over two periods: 0.54 cases per 100,000 race entries in the years 2000–2010, and 0.60 cases in the years 2010–2023. The number of cases has barely moved.
Two other figures have changed a lot. Cardiac deaths fell from 0.39 to 0.20 per 100,000 race entries. Among those who had a cardiac arrest, the death rate fell from 71% to 34%, meaning that in the past, out of every 10 people whose heart stopped, about 7 did not survive, and now it is about 3. More people are being saved, and the authors recorded what saved them: cardiopulmonary resuscitation (CPR) started by bystanders, together with automated external defibrillators (AEDs) placed along the course.
The same data show where the risk is concentrated. Middle-aged men are the highest-risk group, marathons more than half marathons, and the leading cause today is coronary artery disease (narrowing of the blood vessels that supply the heart). Because these are cases recorded at races, they tell us what happened and to whom. How many cases a check-up beforehand would prevent, these data cannot yet answer.
The risk is rare, but you happen to be in its highest group. That is not a reason for the clinic to advise you to stop running. We advise having your heart checked first, getting your running group to take a CPR course together, and before the start, finding out where the race’s medical stations and defibrillators are.
Who should have a heart check-up before registering
ACSM screens people about to start exercising based on three things (Riebe and colleagues, 2015). The first is whether you already exercise regularly. The second is whether you have cardiovascular disease, a metabolic disease such as diabetes, kidney disease, or symptoms of those diseases. The third is how hard you plan to train.
Apply those three things to a middle-aged person about to step up to a marathon or trail race (running on trails and mountain paths), and it is easy to see who needs a doctor’s opinion: people who do not yet exercise regularly, and people who have a disease or symptoms. Anyone who also has one of the five signs at the start of this article has all the more reason to have their heart checked before pressing “register”.
As for what the cardiology check-up includes, the cardiologist decides for each person. There are a few points here that the sources we consulted do not answer. The books do not give an age cutoff for what counts as “early” when a family member dies suddenly, nor say how many generations back to count. For the ACSM guidance, we have only been able to read the summary, not each screening step, and we have not found any heart check-up guidance specifically for middle-aged long-distance runners. That is why the clinic does not set its own age cutoff, and this article does not give a single list of tests for everyone.
Have the check-up before you register, not after. The results may lead you to choose 21 km instead of 42 km, or to put it off until next race season. Once the fee is paid and the shirt collected, it is easy to find reasons to still stand at the start line.
Forty isn’t old
Friends of the same age often talk each other into races with the line “forty isn’t old”. In those conversations, the worry that comes up most is the knees. When it comes to the knees of recreational runners, that line has data to back it up. The meta-analysis by Alentorn-Geli and colleagues (2017) found that recreational runners do not have more knee or hip osteoarthritis. In runners who competed for many years, the number of cases tends to edge up, but that rise may still be due to chance alone (not statistically significant), and it has not been shown to be caused by running.
At this age, the fear of wrecking your knees should not be a reason to give up running. The thing to ask the doctor about before choosing a long distance is your heart.
The blood pressure pills next to the phone
Middle-aged people often already take a few medicines every day, and some of them change how the body copes with a long run. The first group to watch is blood pressure medicines in the ACE inhibitor class, angiotensin receptor blockers (ARBs) and diuretics. If you are not sure which group your pill belongs to, bring the blister pack to a doctor or pharmacist and ask. Taking them together with anti-inflammatory painkillers such as ibuprofen or diclofenac before or during a run means the kidneys get less blood, especially on a hot day when you are already dehydrated (Jameson and colleagues, 2018). To be on the safe side, the clinic advises people on blood pressure medicines not to take anti-inflammatory painkillers before a long run. If you are taking a statin to lower blood fats and are aiming for a hilly race, check again with the doctor who prescribed it before you register.
The traditional healer Nguyen Huu Duc, in his lectures on high blood pressure (2024), writes that “heavy training is wrong”. On the very next page, he writes that the practitioner must choose the right kind of exercise for each person, and must know many kinds of exercise, including running. Read the two pages together and it is clear that his point is moderation and choosing exercise that suits the patient. He does not tell people with high blood pressure not to run.
Herbal decoctions also have to take the heart into account. Gan cao (Glycyrrhiza uralensis root, licorice) is a harmonizing herb found in a great many formulas. In large doses or with long use, it can cause swelling, raise blood pressure and lower potassium (Chinese Materia Medica; Takao and colleagues, 2015). For runners, the clinic keeps Gan cao to no more than 2 g a day, counting decoctions, teas and self-bought lozenges together. For people with high blood pressure, heart disease, kidney disease or low potassium, or who are taking diuretics, digoxin or corticosteroids, the formula contains no Gan cao.
What the clinic does, and where it refers you
Tam Duc Clinic does not do ECGs, heart ultrasounds or exercise stress tests (monitoring the heart during exertion). At a pre-season visit, the doctor asks carefully about each of the signs above, asks about your family history and reviews the medicines you are taking. If there is any sign, the doctor refers you to a cardiologist first, and only then discusses distance and training plans.
People who recover slowly after long runs may be prescribed a decoction in ready-to-drink 50 ml pouches according to each person’s traditional medicine pattern, with the amount of Gan cao worked out as above.
The subscapularis, once the cardiologist has cleared you to run
The order at the clinic cannot be reversed. Applied Kinesiology (AK) is muscle testing by hand, and muscle testing cannot see into the coronary arteries. A muscle that is strong on the examination table does not tell you whether your heart is safe for running, so this part only begins once the cardiologist has finished the check-up and given the go-ahead.
At that point, middle-aged people about to step up to a marathon are usually tested early on a muscle few people think of: the subscapularis. This muscle lies on the front surface of the shoulder blade; it rotates the arm inward, pulls the head of the upper arm bone down as the arm is raised, and helps keep the shoulder stable through the arm swing over hours of running. In Walther’s muscle–organ table, the subscapularis goes with the heart, both as an organ and as a meridian (the channels of traditional medicine); the nutrients he lists for this muscle include vitamin E, B vitamins and vitamin C (Walther, Synopsis, p. 353).
You sit, raise your arm out to the side at shoulder height and bend the elbow at a right angle. The doctor pushes on the wrist to rotate the arm outward, to see whether the muscle can hold the position. In someone already cleared by a cardiologist, if the subscapularis on one side is working below threshold, meaning weaker than its true strength, that is the point to ask further: how have you been sleeping these past few weeks, how have you been eating, are you taking any extra supplements on your own. You taste a small amount of each vitamin on the list above, and the doctor retests the muscle after each one; a substance that makes the muscle hold firm again suggests a direction for diet and supplements during the season of building up your distance, and is not yet a prescription. In the same visit, the doctor tests the muscles around the hips, knees and ankles for the new distance.
And if chest tightness, breathlessness or palpitations come back at any time, the doctor does not continue muscle testing but sends you back to the cardiologist, even if the subscapularis tests strong.
When to come in for a check-up
The health confirmation box on your phone can wait another week or two. Before you tap it, the chest tightness at the seventh kilometer and your father’s story need to be told to a doctor, and then a cardiologist needs to look at your heart. By then, you will tap the box at the bottom of the page knowing more about your heart.
If you are middle-aged, about to register for a marathon or trail race, and have one of the signs above, or are taking blood pressure or heart medicines and are not sure which ones need care on long runs, book an appointment before you register. Dr. Dinh Ngoc Duc (MD, MSc in Traditional Medicine) will look at the signs, review your medicines and refer you to a cardiologist when needed. Book a consultation.
Worth keeping
- Chest pain or chest tightness during exertion, even if it went away by itself: have your heart checked before registering for a race;
- Chest pain while running: stop, alert the race medical team or call 115;
- Fainting during a run is a reason for a heart check-up; fainting just after the finish: lay the person down, raise their legs, and note how long it takes them to come round;
- At the next death anniversary, ask your relatives whether anyone in the family died suddenly at an early age, and at what age;
- Middle-aged and not yet exercising regularly, or living with heart disease, diabetes or kidney disease: get a doctor’s opinion before stepping up to a marathon or trail race;
- If you take blood pressure medicines, do not take anti-inflammatory painkillers before or during a long run;
- Get your running group to learn CPR together, and find out where the race’s defibrillators are.
References
Sources in Vietnamese
- Nguyễn Hữu Đức. 2024. Bài giảng Bệnh huyết áp cao. T24–25.
Sources in English
- Alentorn-Geli E, Samuelsson K, Musahl V, Green CL, Bhandari M, Karlsson J. 2017. The Association of Recreational and Competitive Running With Hip and Knee Osteoarthritis: A Systematic Review and Meta-analysis. J Orthop Sports Phys Ther. 47(6):373-390. doi:10.2519/jospt.2017.7137. PMID: 28504066.
- Jameson JL, Fauci AS, Kasper DL, Hauser SL, Longo DL, Loscalzo J, editors. 2018. Harrison’s Principles of Internal Medicine. 20th ed. New York: McGraw-Hill Education. p. 2145–2147, 3286.
- Joyce D, Lewindon D, editors. 2016. Sports Injury Prevention and Rehabilitation: Integrating Medicine and Science for Performance Solutions. London: Routledge. p. 63–64.
- Kim JH, Malhotra R, Chiampas G, d’Hemecourt P, Troyanos C, Cianca J, et al. 2012. Cardiac arrest during long-distance running races. N Engl J Med. 366(2):130-40. doi:10.1056/NEJMoa1106468. PMID: 22236223.
- Kim JH, Rim AJ, Miller JT, Jackson M, Patel N, Rajesh S, et al. 2025. Cardiac Arrest During Long-Distance Running Races. JAMA. 333(19):1699-1707. doi:10.1001/jama.2025.3026. PMID: 40159341.
- Papadakis MA, McPhee SJ, Rabow MW, et al., editors. 2022. CURRENT Medical Diagnosis and Treatment 2022. New York: McGraw-Hill. p. 378, 459, 870.
- Riebe D, Franklin BA, Thompson PD, Garber CE, Whitfield GP, Magal M, et al. 2015. Updating ACSM’s Recommendations for Exercise Preparticipation Health Screening. Med Sci Sports Exerc. 47(11):2473-9. doi:10.1249/MSS.0000000000000664. PMID: 26473759.
- Roberts WO, Armstrong LE, Sawka MN, Yeargin SW, Heled Y, O’Connor FG. 2021. ACSM Expert Consensus Statement on Exertional Heat Illness: Recognition, Management, and Return to Activity. Curr Sports Med Rep. 20(9):470-484. doi:10.1249/JSR.0000000000000878. PMID: 34524191. Republished in: Curr Sports Med Rep. 22(4):134-149. PMID: 37036463.
- Takao Y, Takaoka Y, Sugano A, Sato H, Motoyama Y, Ohta M, et al. 2015. Shakuyaku-kanzo-to (Shao-Yao-Gan-Cao-Tang) as Treatment of Painful Muscle Cramps in Patients with Lumbar Spinal Stenosis and Its Minimum Effective Dose. Kobe J Med Sci. 61(5):E132-7. PMID: 27363396.
- Walther DS. 2000. Applied Kinesiology: Synopsis. 2nd ed. Pueblo (CO): Systems DC. p. 353.
- Yoshino T, Shimada S, Homma M, Makino T, Mimura M, Watanabe K. 2021. Clinical Risk Factors of Licorice-Induced Pseudoaldosteronism Based on Glycyrrhizin-Metabolite Concentrations: A Narrative Review. Front Nutr. 8:719197. doi:10.3389/fnut.2021.719197. PMID: 34604277.
Sources in Chinese
- 高学敏, 主编. 中医药学高级丛书 · 中药学. 第 1637–1638、1651 页.
- 钟赣生, 主编. 中药学. 第 647 页.
