Can Body Mass Index Values and/or Player Position be Viable Predictors for Exertional Heat Illness in American Football Players?

Background: Exertional heat illnesses (EHIs) affect thousands of high school athletes each year. Although there are clear risk patterns for fatal EHIs based on player characteristics, there is less information on these associations for nonfatal EHIs.

Hypothesis: Prediction of nonfatal EHI risk in American high school football participants can be determined using commonly available data on body mass index (BMI) values and/or player position.

Study design: Epidemiological study.

Level of evidence: Level 3.

Methods: Participants from 22 high schools in the state of Georgia in the United States were used for this study. Player demographics including height, weight, BMI, and player position were considered. EHI occurrences from 2012 to 2014 were recorded and analyzed to determine EHI risk. These data were collected as part of normal practice/competition activities, and the researchers did not interact with the subjects of the study. Therefore, approval from the Institution's Internal Review Board was not required for this investigation.

Results: There were 309 EHIs over 163,118 athlete-exposures. The linemen group had over 2.5 to 3 times greater risk of sustaining heat syncope/heat exhaustion (HS/HE) than the backs (relative risk [RR], 2.63; 95% CI, 1.59-4.33) and Specialists (RR, 3.16; 95% CI, 1.52-6.56) groups. Linemen were at lower risk for exercise-associated muscle cramps (EAMCs) compared with backs (RR, 0.63; 95% CI, 0.53-0.76). No differences were found in relative risk among BMI categories.

Conclusion: Our results indicate that field position is a bigger differentiator in EHI risk than BMI.

Clinical relevance: Sports medicine and coaching staff should be educated that American football participants at the linemen position are at greater risk for HS/HE than those at other positions. This supports the use of position-specific training activities to mitigate EHI risk.