So it turns out that I’m running a marathon this weekend.
Call it peer pressure, or perhaps some navel-gazing around a “significant birthday” that I have in a few weeks. Either way, my wife convinced me about six months ago to run the Portland Marathon. In full disclosure, this wouldn’t be my first time flirting with shin splints — I have gone the distance three times before, although in three very different settings:
- Age 22: A friend and I dared each other to run the Boston Marathon on a Saturday night. We limped across the finish line the following Monday. Couldn’t walk for a week.
- Age 23: A friend dared me to run the Madrid Marathon while we were backpacking across Europe. I stopped for a glass of red wine at mile 23 (I was in Spain, right?). Couldn’t walk for two weeks.
- Age 29: My girlfriend (see “wife” above) dared me to run a flat marathon along the New Jersey shore. I trained a bit, and we crossed the finish line together. Walked her down the aisle the following year.
Fast forward a decade (or more), and here I am contemplating the race this weekend, as well as my propensity to accept dares to run marathons. Fortunately, I am better trained. But I am also older. I can’t help but wear my cardiologist’s stethoscope now and again and wonder about the toll that this type of adventure takes upon a body – and a heart.
We know that abnormal heart rhythms are more likely in athletes who compete in endurance events. We also know that blood tests demonstrating evidence of microscopic heart damage and elevated markers of inflammation are abnormal in about half of runners following a marathon. And we have all heard about the tragedies of sudden death occurring in seemingly healthy individuals during a race.
But the good news is that these events are uncommon: on the order of 1 in 100,000 runners. And when we look more carefully at the autopsy data, we recognize that though the most common cause of sudden death in athletes under age 35 is hypertrophic cardiomyopathy, the most common cause in older individuals is, by far, coronary artery disease.
So if you’re older than 35 and are contemplating a marathon, a triathlon, or even a gym membership, do you need to see a cardiologist? Should you be screened in some fashion? Should you undergo an exercise treadmill test?
It depends. While a simple office-based exercise treadmill test has excellent prognostic value in people with symptoms such as chest pain or exertional shortness of breath, they are not as accurate in people who feel well. They may be abnormal in only about half of people with significant coronary artery disease, and a 10-minute test is unlikely to replicate the physical toll of a four-hour race. Not to mention the false positives that can lead to more expensive or invasive testing.
The other issue is about how heart attacks happen. The conventional wisdom is that a coronary artery blockage develops slowly over time, and ultimately blocks the vessel entirely, thereby causing a heart attack. But we now know that a heart attacks usually occur differently.
In about 70% of people having a heart attack, a previously milder blockage (less than 50%) suddenly becomes much more significant, usually due to the development of a blood clot at the site of a plaque rupture in the wall of the vessel. This sudden process can explain why people who previously had no symptoms can develop a heart attack. And the scary news is that their stress testing might have normal.
So what’s a weekend warrior to do? Take a look at yourself first. If you have a risk factor for a coronary artery disease – such as high blood pressure, abnormal cholesterol, or diabetes, make sure you are on top of it. Hopefully you aren’t contemplating crossing the finish line jones-ing for a cigarette. And if you do have a family history significant for coronary artery disease or sudden death — especially in younger individuals — you should let your doctor know. If you have any symptoms — like chest pain with exertion, shortness of breath, palpitations, or dizziness with exercise, please see your doctor and get cleared before the starting gun goes off.
Race events like marathons are a great way that we can motivate one another to adopt healthier lifestyles (even if it’s from a dare!). Let’s use these opportunities to reduce our own personal risk so that every race can be finished as safely as it begins.
Off to carb-load!