WHEN BRONNY JAMES collapsed in July, the shock of what happened was perhaps outstripped only by the surprise of the circumstances surrounding the incident. At just 18 years old, James—the son of undoubtedly one of the best professional hoopers of all time, LeBron James—went into cardiac arrest during a routine practice. A fit guy in prime shape—a budding superstar getting ready to play for a Division I basketball program, no less—was rushed to the hospital and placed in intensive care.
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Bronny James goes up for a dunk during a high school basketball game in January 2023, six months before he went into cardiac arrest.
Such a turn of events prompts the obvious question: Why did a young athlete in top form, with access to elite medical care, suddenly find his heart malfunctioning? James, though, is not the first young athlete who’s experienced cardiac arrest, and he will not be the last. Which prompts the next obvious question: How do young athletes even have heart problems? The answer comes down to the nature of the muscle itself and the role that exercise sometimes plays in triggering potentially deadly events.
Cardiac arrest taking down young, competitive athletes is actually not a new phenomenon. Recent data from the Sports Institute at the University of Washington puts the rate of cardiac arrest at about two in every 100,000 young athletes each year. Guys are especially susceptible: For reasons that befuddle cardiologists, cardiac arrest is five times as likely to happen in male athletes as female athletes, according to Jonathan Kim, M.D., director of the Sports Cardiology program at Emory University and chair of the Sports and Exercise Cardiology Section for the American College of Cardiology.
High-profile incidents among athletes—James over the summer and Buffalo Bills safety Damar Hamlin (age 24 at the time) in January—make it seem as though fit young guys are in the crosshairs: that to be young and in shape, and therefore exercising all the time, puts you at risk. In reality, those factors generally help your heart. Yet things can still go wrong.
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Why the Beat Goes Off
CATASTROPHIC CARDIAC issues affecting young people, athletes or not, are usually the result of an inherited structural or electrical abnormality of the heart muscle. But the problem isn’t always detected until disaster strikes. “Many times these diagnoses can go without symptoms where, believe it or not, sudden cardiac arrest may be the first manifestation of the process,” Dr. Kim says.
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Buffalo Bills safety Damar Hamlin on the sidelines prior to experiencing cardiac arrest that same night in January 2023.
During cardiac arrest, the heart’s normal rhythm is interrupted by a lethal arrhythmia. The organ, in turn, stops pumping blood. It’s normal for the heart to beat more rapidly during exercise, of course, but an arrhythmia is an irregular heartbeat. It can be irregular in more than one way. Ventricular tachycardia is one type of arrhythmia where the heart does not beat, and the result is cardiac arrest. “Cardiac arrest usually causes someone to collapse instantly,” says Lili Barouch, M.D., who heads up the Johns Hopkins Sports Cardiology Program.
In athletes with underlying heart problems, exercise can be a unique catalyst in bringing on cardiac arrest. According to Dr. Barouch, the risk increases for anyone who’s exercising, regardless of whether they’re active all the time or have a more sedentary lifestyle, but the overall threat is much lower for those who exercise regularly. The danger, though, is higher for someone with a vulnerable heart due to genetic, structural, or electrical abnormalities. Multiple other variables—dehydration, electrolyte imbalances, a surge of stress hormones such as cortisol and adrenaline—might increase the risk of a dangerous arrhythmia during practices or workouts. The exact link between exercise and the heart, however, remains a puzzle. “We don’t have the full answer of why exercise itself is a risk,” says Dr. Barouch, “but we think it’s a combination of all those things.”
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Former Philadelphia Flyers hockey player Chris Pronger warms up with his team over a decade after he collapsed on the ice from commotio cordis, a form of cardiac arrest.
This perhaps explains what happened to Bronny James—who, as it was revealed after his episode, likely has a congenital heart defect. Sometimes medical screening catches these problems; sometimes it doesn’t. (There’s not enough information on James’s case to determine whether it would have caught his, and his family foundation did not respond to requests for comment.) But not all cardiac arrests are the fault of a broken heart. Six months before James’s collapse, Hamlin crumpled to the field after getting hit in the chest while making a tackle. In April, he disclosed the culprit: commotio cordis. Latin for “agitation of the heart,” commotio cordis is a rare cardiac arrest following a blow to the chest at a precise moment in the cardiac cycle, a window that’s milliseconds wide. Immediately, the heart goes into ventricular fibrillation, another type of arrhythmia. This is the same thing that happened to St. Louis Blues defenseman Chris Pronger in 1998 after he took a slap shot right to the chest.
“Commotio cordis can happen to anybody,” says Dr. Barouch. “It’s just super, super unlucky. It’s like getting hit by lightning.” Hamlin, understandably, was shaken. “I’m still trying to process all the emotions and the trauma that comes from, you know, dealing with a situation like that,” he said in a Good Morning America interview almost a month after the incident. “It could have been the last of me.” At first, he didn’t talk about it a lot. Since then, he’s been working to help people with heart conditions share their stories (through HeartMates, a partnership with Abbott) since, he says, people who haven’t been through it don’t always understand the fear, anxiety, and other emotions. “I had to rebuild myself from ground zero,” he says.
How Age Makes a Difference
FOR ALL THE attention paid to young athletes who suffer cardiac arrest, the group that is in fact much more at risk is what doctors call “masters athletes”—generally, any physically active person over the age of 40. The reason is simple: The older you get, the more likely you are to develop coronary artery disease, increasing your chances of having a heart attack—that’s when a plaque rupture or blood clot clogs the coronary artery. This, in turn, can potentially lead to cardiac arrest.
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Doctors are still trying to decipher the interplay between vigorous activity and heart attacks. While exercise is beneficial for the health of your heart, in some cases intense physical activity might generate a sudden plaque rupture.
Exercise-induced heart attacks in masters athletes, though, remain relatively rare. For instance, a study that’s regarded as the most definitive so far looked at almost 11 million marathoners over a period of ten years and found the incidence of sudden cardiac death to be a mere 0.54 per 100,000 runners.
Working out, even via long, daily walks, is a good way to head off heart disease. Just consider a 2014 study published in the Journal of the American College of Cardiology: No matter how often or infrequently runners trained and raced, they were about 45 percent less likely than nonrunners to die from heart disease or stroke. “We know exercise is medicine,” Dr. Kim adds. “The more you exercise, the less you’re at risk for having a heart attack.”
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Why Screening Isn’t the Answer
ATHLETES YOUNG AND old, professional and amateur, might wonder if cardiac screening could catch a heart complication before it emerges. This question of whether to screen athletes—or anyone embarking on an exercise routine—in the first place is a continuing matter of debate among cardiologists.
“Some level of screening is needed, but more is not necessarily better. You could go nuts doing imaging studies on everybody’s heart and you’d still miss a bunch of stuff,” says Dr. Barouch. Even a battery of tests, including an electrocardiogram (aka an EKG, a tool that shows the electrical activity of the heart) or an echocardiogram (also called an echo, an ultrasound of the heart), sometimes only gives the illusion of heart health. A study published in The New England Journal of Medicine tracked more than 10,600 16-year-old soccer players in the United Kingdom over 20 years via an EKG or an echo. The researchers found that while the screenings picked up congenital abnormalities and other cardiac disorders in about 3 percent of the players studied, they also produced completely normal results for six players who later were felled by sudden cardiac death.
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KJ Hamler runs the ball during a Broncos game in November 2020, three years before he was diagnosed with pericarditis, a mild heart irritation.
That doesn’t mean you should skip screenings (or exercise) altogether. Michael Emery, M.D., codirector of the Sports Cardiology Center at the Cleveland Clinic, counsels his patients to do two things. Number one: “Make sure that if you’re planning to do something intense, you’ve trained yourself up for that,” he says. “Two is to make sure that you’re not ignoring any symptoms that you may have.” Dizziness, fainting, and chest pains are signs that shouldn’t be ignored.
Easing into strenuous physical activity is not only a helpful way to see if you’re fit enough to take it on; it also acts as a barometer for whether your heart is able to handle the action. If brisk walking, for example, is leaving you short of breath or with chest tightness, that’s a clear indicator that there might be a hidden problem. Pay attention to what your body tells you.
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Over the summer, it was reported that Denver Broncos wide receiver KJ Hamler would miss at least part of this year’s NFL season due to a diagnosis of pericarditis, a mild irritation of the heart. Doctors caught it when Hamler complained of chest pains after workouts. It turns out there may be signals from your body prior to cardiac arrest as well. A study published in The Lancet Digital Health this past August found that half of the people who suffered a sudden cardiac arrest had experienced some type of symptoms in the previous 24 hours. For most men, those were chest pains and pressure. Smaller groups of men reported shortness of breath or abnormal sweating.
Being proactive by exercising and telling your doctor about any symptoms is the best way to prevent a life-threatening cardiac event. Diet advice may be as tired as a runner after a race, but it’s worth keeping tabs on what you’re eating, too. Aim for an inclusive eating pattern that focuses on fruits and vegetables along with whole grains, lean protein, and olive oil. That means salmon, almonds, spinach, and legumes are in. Pass on the double cheeseburger when you can.
If you experience dizziness or chest pains after a hard workout, that’s one reason to be evaluated by your doctor. If you pass out during a workout, that’s another reason. If your family tree is loaded with heart disease or cardiac arrest, that’s yet another cause for a conversation with a physician—particularly if you’re planning to start training for, say, next year’s marathon. In these situations, your doctor might want you to undergo a complete evaluation, which could include an EKG. “For sure, EKGs can pick up some abnormalities that a history or a physical cannot,” says Dr. Kim. “However, we also understand that just because you find things, it doesn’t necessarily mean you’re actually saving a life.”
What all cardiologists, including Dr. Kim, Dr. Barouch, and Dr. Emery, do agree on is the value of coaches and teams forming a plan and having people (including you) learn how to administer CPR and work an AED. (See “Saving a Life: The Play-by-Play.”) “Whether you’re having symptoms, whether you have known a disease, whether you don’t have a disease, that emergency action plan and that AED availability save lives,” says Dr. Emery. “That’s the one thing we’ve absolutely, 100 percent positively proven.”
Following the steps in our story, How to Do CPR the Right Way, can save the life of a competitor on the marathon course, a buddy during a pickup game, or a friend at the gym. Indeed, those very steps are exactly what saved the lives of Damar Hamlin and Bronny James—ensuring that the two are still star athletes, instead of statistics, whom we’ll get to watch for years to come.
This article appears in the December 2023 issue of Men’s Health.
