Marathon and Sudden Death....Can anyone prevent it?

Lately, it seems 'sudden death associated with marathon running' was getting an unusually high publicity. Certainly giving marathon a pretty bad rap. The recent death of a runner in a 5km Passion Run sparked the topic yet again and runners are now asking themselves: Could this happen to me?

To marathoners, the question pretty much on our mind is: What can I do to prevent this? Or is there ANYTHING I can do? You have probably heard of Ryan Shay, whose untimely death in the Olympic Marathon Trials in 2007 shocked the world. He was 28 years old. Cause of death: Massive Heart Attack due to a pre-existing enlarged heart.

Before we explore this issue, I think we need to understand some basic facts before we jump into conclusions based on emotion or hearsay. Though I am not 'exempted' from this (being an avid marathoner), but as a medical professional, I can and will be as objective as possible in tackling this.

So, let's ask some questions:

What is "sudden cardiac death"? Physicians define this as: "sudden death" in young athletes (women as well as men, ages 35 and younger) as a nontraumatic, nonviolent, unexpected death due to cardiac causes within one hour of the onset of symptoms.

Exactly how common is this? What is the actual incidence? Some studies suggest that the incidence of sudden cardiac death in unscreened men during exercise is 1 in 280,000 per year. As for studies of the risk of death in marathons, it's been estimated that one death would occur in 50,000-88,000 marathon finishers.What does that mean? At first glance, does it mean marathoners are more at risk? Not necessarily. The former is the incidence of mortality in a year whereas the latter is the risk within a population of marathoners. They are different things. But some other studies suggest that the risk in distances between 10km and half-marathon is even lower: ~3.1 deaths per million finishers. Other interesting study states that there is a 56 time greater risk during exercise in sedentary men and only 5 time greater risk during exercise in active men!

In other words, the incidence is very low. Certainly in comparison to the sedentary population, we are approximately 10 times less at risk of sudden cardiac death. But nonetheless, since there is still a risk, we need to see what are these causes so that we can avoid it if at all possible.

But before that we need to understand that not all "enlarged heart" is pathological. I have a personal experience in that. When I was 16 years old, I was a sprint athlete in the 400m event. Due to strenous training, I had the occasional chest pain and that worried my parents who promptly had me examined by a cardiologist. He detected a murmur and referred me onwards to another cardiologist in Mt E (Singapore). The doctor confirmed an enlarged heart on ECHO. But what he did next was probably unnecessary: (More about that another time!) He performed an angiogram on me. (Yes I had an angiogram at 16 years of age!) Conclusion? I have an athlete's heart. So, an enlarged heart may not be pathological at all. But this is a diagnosis by exclusion of other more sinister causes....

There are more than 20 pathological conditions identified as causes of sudden death in athletes. We will just look at a couple that are responsible for most of these deaths that are reported.

Firstly, Hyperpertrophic Cardiomyopathy. Rare in the general population, (0.1% to 0.2% prevalence). But it is the most common cause of sudden cardiac death in young athletes. It is inherited and 60% of individuals with this have an affected first-degree relative. Individuals may present with sudden cardiac death as their first (and therefore last) and only symptom of a hypertrophic heart.

The second leading cause is Coronary Artery Abnormalities. Only about one third of affected individuals are thought to be symptomatic (experiencing angina (chest pain), syncope (fainting), or shortness of breath with exercise) before sudden death. The mechanism of sudden death in all cases here is due arrhythmia (abnormal heart rhythm) triggered by heart tissue ischemia or infarction (or commonly heart attack).

At the end of the day, who are the ones that should see a physician? The following is a recommended guideline.

1. Strong family history of cardiac disease or sudden cardiac death.

2. If you have chest pain or shortness of breath that comes on during training.

3. Pre-morbid factors such as High Cholesterol with high LDL and low HDL, Hypertension (High blood pressure) and Diabetes.

In any case, a person who fulfills any one of the above criteria should be reviewed at least yearly or as frequently as indicated by the physician. Even if you do not have any of those conditions, still, there is no harm in doing an annual check up. In most cases, a physical examination and ECG is all that's required.

So, don't be stubborn and think that: "O, it will never happen to me." "I have never been fitter, why should I need to see a doctor?" Ryan Shay would not have known it either.

If it checks out OK, then at least you have done your part in it. (If God still decides to bring you back to Glory, I am sure He has many alternate ways!) Besides you are not just doing this for yourself, think of your family and loved ones. If you still choose to remain in ignorance or denial, you may not be just endangering yourself but them too.

Lastly, I am a Paediatrician. So, I think I am quite neutral in this matter. I don't have any cardiologist relatives or friends that may "benefit" from this. So, rest assured that this comes from my heart. (and mind)....


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