There has been a good deal of media attention in recent years about cardiac arrests and deaths associated with marathons and half-marathons. Even Edward M. Wojtys, MD, Editor-in-Chief of the journal Sports Health commented on the deaths of three runners competing in the Detroit Free Press Half Marathon in October 2009, all from presumed cardiac events. “How sad! Men trying to stay in shape by running and paying for it with their lives! There are risks associated with most sports, but usually the consequences are much less severe than death,” he wrote in the January/February 2010 issue of the journal.For those of you apprehensive about the risk of cardiac arrests at marathons and half-marathons, there is some news that hopefully will allay some fears. A study published in The New England Journal of Medicine examines cardiac arrests that occurred in marathons and half-marathons across the United States from January 1, 2000, to May 31, 2010. A prospective database of cardiac events occurring during or immediately after these races across the Unites States was developed, and the data was analyzed and published by Jonathan H. Kim, M.D. et al.

There were several interesting findings from this study that I would like to share.

-There were 59 cardiac arrests during this period, and 40 occurred in marathons and 19 in half-marathons. The incidence rate of cardiac arrest in these events was 1 in 184,000 participants. Male marathoners made up the highest risk group. Tweet this statistic.

-42 of the 59 runners who suffered cardiac arrest died (71%). Therefore, the incidence rate of sudden death in these events was 1 in 259,000 participants. Again sudden deaths were more common in males than females and during marathons rather than half-marathons.

-Of the runners who died and where complete medical information could be obtained, hypertrophic cardiomyopathy was the most common underlying cause. HCM is a condition where the heart muscle lining of the ventricle is thickened. It is a very common cause of sudden death in young athletes. It appeared to have a poor prognostic factor in this study, meaning that runners with HCM who suffered cardiac arrest frequently died.

-Coronary artery disease (atherosclerosis) was the most common underlying condition in those who survived.

-The strongest predicting factors for survival of these runners after cardiac arrest was bystander initiation of CPR and an underlying diagnosis other than hypertrophic cardiomyopathy.

-The rates of sudden deaths from marathons and half-marathons in this study compare favorably to other sports and exercise:
College sports – 1 death per 43,770 participants per year
Triathlons – 1 death per 52,630 participants per year
Healthy middle-aged joggers – 1 death per 7620 participants

-The fatality rate of deaths after cardiac arrests during marathons and half-marathons (71%) in this study is significantly lower than has been shown in prior studies of fatality rates with out-of-hospital cardiac arrests.

Points to consider about cardiac arrests at marathons

Now for the roughly 2 million people who compete in marathons and half-marathons each year in the United States, this study should come as relatively good news. While cardiac arrests and deaths can and do occur in these long-distance running events, they are unlikely. They appear to be less common adverse events than would occur with college sports or even casual jogging. But this study does shed light on a few points that might keep runners even safer.

Know cardiopulmonary resuscitation (CPR).

The rate of deaths after cardiac arrest appear to be much lower than those that occur everywhere else, other than at hospitals. This increased survivorship most likely has to do with bystanders immediately nearby starting CPR and medical personnel on site. And the authors did show that runners who underwent CPR quickly were more likely to survive.

Therefore, I think it is imperative for runners and their families, as well as spectators generally, to know how to administer CPR. And race officials might consider working with the medical teams covering the race to have personnel trained in CPR spread out along the course to perform it if needed, rather than having all personnel in a medical tent at the finish line. Whatever decreases the time between the cardiac event and the initiation of CPR would be helpful.

Undergo a physical before running a marathon.

One could make a compelling argument that someone considering training for a marathon or half-marathon should see his or her doctor and undergo a thorough physical and obtain labs and tests if needed. This recommendation seems especially applicable to males. As this study showed, hypertrophic cardiomyopathy is a significant risk factor for sudden death in these races, just like in all sports. And frequently athletes suffer sudden death without ever knowing they have HCM. A good physical exam, plus an electrocardiogram and echocardiogram if deemed necessary by the physician, can detect this condition.

Another interesting point that this study suggests could become a helpful option is the idea to screen marathon and half-marathon participants the day before a race. Whether some sort of easily administered stress test is feasible or financially possible is unknown, but if the race’s medical personnel could identify those at risk for cardiac events before they occur, it might be worthwhile.

Runners with any symptoms at all need to see their doctor.

Anyone with symptoms of chest pain, shortness of breath, lightheadedness, or anything unusual needs to have it checked immediately.