title: Exertional Heat Illness in American Football Players: When Is the Risk Greatest?
abstract: BACKGROUND
  Knowledge about the specific environmental and practice risks to participants in American intercollegiate football during preseason practices is limited. Identifying risks may mitigate occurrences of exertional heat illness (EHI).
  
  
  OBJECTIVE
  To evaluate the associations among preseason practice day, session number, and wet bulb globe temperature (WBGT) and the incidence of EHI.
  
  
  METHODS
  Descriptive epidemiology study.
  
  
  METHODS
  Sixty colleges and universities representing 5 geographic regions of the United States.
  
  
  METHODS
  National Collegiate Athletic Association football players.
  
  
  METHODS
  Data related to preseason practice day, session number, and WBGT. We measured WBGT every 15 minutes during the practice sessions and used the mean WBGT from each session in the analysis. We recorded the incidence of EHIs and calculated the athlete-exposures (AEs).
  
  
  RESULTS
  A total of 553 EHI cases and 365 810 AEs were reported for an overall EHI rate of 1.52/1000 AEs (95% confidence interval [CI] = 1.42, 1.68). Approximately 74% (n = 407) of the reported EHI cases were exertional heat cramps (incidence rate = 1.14/1000 AEs; 95% CI = 1.03, 1.25), and about 26% (n = 146) were a combination of exertional heat syncope and heat exhaustion (incidence rate = 0.40/1000 AEs; 95% CI = 0.35, 0.48). The highest rate of EHI occurred during the first 14 days of the preseason period, and the greatest risk was during the first 7 days. The risk of EHI increased substantially when the WBGT was 82.0°F (27.8°C) or greater.
  
  
  CONCLUSIONS
  We found an increased rate of EHI during the first 14 days of practice, especially during the first 7 days. When the WBGT was greater than 82.0°F (27.8°C), the rate of EHI increased. Sports medicine personnel should take all necessary preventive measures to reduce the EHI risk during the first 14 days of practice and when the environmental conditions are greater than 82.0°F (27.8°C) WBGT.
authors: Department of Kinesiology, University of Georgia, Athens.
authors: Earl R
authors: ER
authors: Cooper
authors: College of Health and Human Services, University of New Hampshire, Durham.
authors: Michael S
authors: MS
authors: Ferrara
authors: Korey Stringer Institute, University of Connecticut, Storrs.
authors: Douglas J
authors: DJ
authors: Casa
authors: Department of Kinesiology, Michigan State University, East Lansing.
authors: John W
authors: JW
authors: Powell
authors: NeuroTrauma Research Laboratory, University of Michigan, Ann Arbor.
authors: Steven P
authors: SP
authors: Broglio
authors: Department of Kinesiology, University of Virginia, Charlottesville.
authors: Jacob E
authors: JE
authors: Resch
authors: Ronald W
authors: RW
authors: Courson
mesh_terms: D005538:Football / Q000293:injuries*; D018882:Heat Stress Disorders / Q000453:epidemiology*; D006358:Hot Temperature; D006801:Humans; D015994:Incidence; D008297:Male; D012307:Risk Factors; D013334:Students; D014481:United States / Q000453:epidemiology
keywords: environmental conditions; heat injuries; weather monitoring; wet bulb globe temperature