AJPM paper addresses exertional heat illness and death among high school athletes

Zachary Kerr

Kerr is a graduate research assistant in UNC Gillings School of Global Public Health’s Department of Epidemiology. His paper, “Epidemiology of Exertional Heat Illness Among U.S. High School Athletes,” were published online Oct. 23 in the November issue of the American Journal of Preventive Medicine [PDF].

Stephen Marshall, PhD, professor of epidemiology at UNC’s public health school and director of the UNC Injury Prevention Research Center, is a co-author. Marshall also is an adjunct professor in the UNC Department of Exercise and Sport Science.

The authors note that an estimated 9,000 high school athletes are treated for exertional heat illnesses (EHI) every year. Most of those occur in August, at the beginning of the fall sports season, when athletes are not yet acclimated to physical exertion in the heat.

They determined that the incidence rate of nonfatal EHI for high school sports is 1.2 per 100,000 athlete exposures (defined as one athlete participating in one athletic practice or competition). They also found that the rate of nonfatal EHI in football was more than eleven times the rate in all other sports combined.

The authors note that the rate of athlete deaths is increasing.

“Between 1995 and 2010, a total of 35 football players died from exertional heat stroke (EHS), an average of two annually,” they write. “In summer 2011, six high school football players died due to high temperatures and lack of rehydration. In the five-year block from 2005 to 2009, more EHS deaths occurred in organized sports than in any other five-year period over the past 35 years.”

A key new finding from this study is that EHI events took place across the U.S. and in all geographical areas, not just in hot or humid areas. While it is true that most EHI events occurred in football, the authors found that athletes in all sports are at risk. Athletes experienced EHI events in 14 additional sports, including field hockey, lacrosse, volleyball, wrestling, baseball, soccer, swimming and diving, and track and field.

Another new finding was that although all high schools in the study had certified athletic trainers who serve as frontline sports medicine professionals, one-third of all EHI events occurred when the school’s athletic trainer was not present. Typically, this was because multiple teams practice and compete after school, and there is only one athletic trainer, Kerr said.

Nationwide, only 42 percent of high schools have access to certified athletic trainers. Improving access to certified athletic trainers should be a national priority, Kerr said. In addition, many athletes and coaches lack knowledge to identify and treat EHI. It is therefore imperative, the authors write, that high school athletes, coaches, administrators and parents are trained to identify and respond to exertional heat illnesses. “Implementing effective preventive measures depends on increasing awareness of exertional heat illness and relevant preventive and therapeutic countermeasures,” they said.

To better track and care for EHI, the study offers strategies to improve surveillance and information gathering, including:

• Note types of health-care professional (if any) onsite at time of onset;
• Document the setting (e.g., club, high school, middle school) and characteristics (athletic trainer staff size, number of student-athletes);
• Ensure athletic staff are properly trained in utilizing prevention strategies to reduce incidence and severity of EHI, such as monitoring temperature and humidity;
• Track whether proper treatment of EHI (i.e., rapid cooling) occurred;
• Include nationally representative samples of athletes from multiple sports; and
• Increase education regarding EHI and how to prevent it.

Other co-authors include Douglas J. Casa, PhD, from the University of Connecticut’s Korey Stringer Institute and R. Dawn Comstock, PhD, of the Center for Injury Research and Policy at Nationwide Children’s Hospital’s Research Institute.

The study was funded by the Society for Public Health Education Student 2012 Fellowship in Injury/Violence Prevention and Control.