Author + information
- †University of Iowa, Iowa City, Iowa
- ‡Mercy Hospital, Mason City, Iowa
- §Good Samaritan Hospital, Los Angeles, California
- ‖Cedars-Sinai Heart Institute, Los Angeles, California
- ¶UCLA School of Medicine, University of California-Los Angeles, Los Angeles, California
- ↵∗Reprint requests and correspondence:
Dr. David S. Cannom, Good Samaritan Hospital, 1245 Wilshire Boulevard, #703, Los Angeles, California 90017.
When I (David S. Cannom) began long-distance running 40 years ago, there were very few runners and little information about the cardiac effects of long-distance running. One of the members of our Sunday morning running group, a cardiologist named Dr. Tom Bassler, wrote that “The American Medical Joggers Association has been unable to substantiate a single ischemic heart disease death among marathon finishers of any age” (1). Five years later, the famous runner Jim Fixx died of a myocardial infarction during a training run and the Bassler myth exploded. For the last 25 years, the cardiac literature has sought to define more carefully the cardiac risk of sudden death during running and to develop screening methods to assess risk. A recently published exhaustive review of 10.9 million runners participating in 40 marathons and 19 half marathons identified 59 cardiac arrests, each of which was carefully analyzed as to cause (2). The overall incidence of cardiac arrest was 1 of 184,000 participants (0.54 per 100,000). The authors noted that definite or possible hypertrophic cardiomyopathy was the primary cause of death and myocardial ischemia was found in only 16%. They added that “alternative race-related disorders including hyponatremia and hyperthermia remain important causes but are uncommon causes of cardiac arrest and sudden death” (2).
In this issue of the Journal, Yankelson et al. (3) add an important dimension to the debate about causes of death in long-distance runners. Heat stroke, defined as a core body temperature exceeding 104 to 105°F associated with multiorgan dysfunction, was more of a problem than death from any cardiac cause in their Tel Aviv database. Cerebral dysfunction was an important initial symptom. Patients who develop heat stroke may rapidly develop cardiac arrest, and the diagnosis may be missed if rectal core body temperature is not measured soon after a runner collapses. Without an early, accurate diagnosis, the necessary aggressive treatment may not be delivered.
Yankelson et al. (3) analyzed 137,580 runners participating in a series of endurance races (from 10K races to full marathons) in Tel Aviv between March 2007 and November 2013. Complete information regarding medical events at all of these races over 7 years was available at the authors’ hospital. All medical care for these races was provided at the authors’ hospital in Tel Aviv. Care for runners who collapsed also was provided by first responders from this hospital.
Over the 7-year time span, serious adverse events resulting in hospitalization or death occurred in 21 athletes. Two died as a result of participation in the races for a sport-related mortality of 1 of 69,000. Only 2 hospitalizations were for what are considered cardiac conditions: 1 due to an uncomplicated and nonfatal myocardial infarction and the other for an episode of supraventricular tachycardia treated with adenosine and later ablation. The remaining hospitalizations were for cases of exertional heatstroke, including 12 that were life threatening and 2 that were fatal. The patients who died had heat stroke correctly identified but died of multiorgan failure in 1 case and unsuccessful cardiac resuscitation in the other, with a documented temperature of 105°F. The nonfatal cases required intubation and mechanical ventilation but recovered. The physicians and technicians responsible for medical care at the races were trained to diagnose and care for heat stroke. They had the capability to take a rectal temperature in the field when a runner collapsed. The capability of this simple maneuver increased diagnostic yield and was considered lifesaving by the authors.
The message of the paper is 2-fold. The first is that heat stroke is common in warm climates during long-distance running races, and the second is that heat stroke can be successfully treated if it is suspected in a runner who collapses. The emphasis on training the medical team to look for this problem seems to account for the high number of diagnosed cases and the high recovery rate.
The authors point out that no guidelines exist to direct the timing of races based on weather or to enforce medical measures that might ensure better acclimatization of the runners to heat. Inadvertent scheduling of races on warm days in the Midwest was shown to be disastrous when, in the 2007 Chicago marathon, 300 participants experienced heat-related injury.
One concern about the Tel Aviv data is that they may not represent other races or athletic events around the globe. The temperature in Tel Aviv may be warmer than in other locations. This concern does not distract from the main message of the paper.
Heat stroke in organized sports has increased substantially between 2005 and 2009 in athletics beyond long-distance running. In a self-administered online questionnaire of athletic trainers who care for high school football athletes, 20.3% reported at least 1 exertional heat stroke event. Another report between 2005 and 2009 in 100 schools found a total of 118 heat-related illnesses among high school athletes, with a rate of 1.6 of 100,000 athlete exposures and the highest rate of illness among football players at 4.5 of 100,000 athlete exposures. No deaths were reported, but the incidence is increasing (4).
This paper highlights 2 distinct threats to participants in long-distance races: 1 of which is cardiac and the other is an emerging recognition of heat stroke as a cause of multiorgan failure and subsequent death. The best methodology to screen athletes for cardiac disease has been debated over 30 years since we realized that marathons do not secure cardiac immortality. On the other hand, heat stroke has no predictive clinical profile that a screening examination may uncover and can only be diagnosed at the onset of the episode. Eliminating this potentially catastrophic event can be accomplished by having carefully trained medical personnel looking for this problem during the race and initiating treatment in the field. By emphasizing the importance of recognizing heat stroke when it presents and outlining a plan of care, Yankelson et al. have made a valuable contribution to making long-distance running safer.
↵∗ Editorials published in the Journal of the American College of Cardiology reflect the views of the authors and do not necessarily represent the views of JACC or the American College of Cardiology.
Dr. Olshanksy has served as a speaker for Medtronic; and a consultant for Boston Scientific, Amarin, Boehringer Ingelheim, Daiichi Sankyo, Sanofi-Aventis, and BioControl. Dr. Cannom has reported that he has no relationships relevant to the contents of this paper to disclose.
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