Exertional heat-related injuries treated in emergency departments in the U.S., 1997-2006.

BACKGROUND Exertional heat-related injuries are a risk to all physically active individuals in warm or hot environments. Unlike classic heat-related injury, exertional heat-related injuries do not require extreme ambient temperatures to cause injury. Still, exertional heat-related injuries, including heat cramps, heat syncope, heat exhaustion, heat stress, and heat stroke, can result in injuries causing a range of outcomes from minimal discomfort to death. PURPOSE The purpose of this paper was to describe the epidemiology of exertional heat-related injuries treated in U.S. emergency departments. METHODS A retrospective analysis was conducted using data from the National Electronic Injury Surveillance System of the U.S. Consumer Product Safety Commission for all ages from 1997 through 2006. Data provided by the National Electronic Injury Surveillance System were used to calculate national estimates of exertional heat-related injuries. Trends of exertional heat-related injuries over time were analyzed using linear regression. RESULTS Nationally, an estimated 54,983 (95% CI=39995, 69970) patients were treated in U.S. emergency departments for exertional heat-related injuries from 1997 to 2006. The number of exertional heat-related injuries increased significantly from 3192 in 1997 to 7452 in 2006 (p=0.002), representing a 133.5% increase. The overall exertional heat-related injury rate per 100,000 U.S. population more than doubled from 1.2 in 1997 to 2.5 in 2006 (p=0.005). Patients aged ≤19 years accounted for the largest proportion of exertional heat-related injuries (47.6%). The majority of exertional heat-related injuries were associated with performing a sport or exercising (75.5%) and yard work (11.0%). The majority of patients (90.4%) were treated and released from the emergency department. Patients aged ≤19 years sustained a larger proportion of sports and recreation exertional heat-related injuries, whereas patients aged 40-59 years and ≥60 years sustained a larger proportion of exertional heat-related injuries from yard work. CONCLUSIONS This study confirms that although there is a risk of exertional heat-related injury among all physically active individuals, sports pose a specific risk for people of all ages especially among children and adolescents playing football. Many "everyday" activities such as yard work and home maintenance also pose risks of exertional heat-related injury, particularly to those aged ≥40 years. Further research on risk factors of exertional heat-related injuries during home maintenance and yard work as well as appropriate prevention practices is needed.