Long-term follow-up after exertional heat illness during recruit training

Purpose: To evaluate long-term susceptibility to subsequent serious exertional heat illness (EHI) in military recruits who suffered exertional heat illness during basic training. Methods: We identified Marine Corps members who completed at least 6 months of military service and suffered EHI treated as outpatients (N = 872) or inpatients (N = 50) during basic training in 1979-1991 at the Parris Island Marine Corps Recruit Depot, SC (EHI cases). We compared them to 1391 similar members (noncases) who did not experience EHI during basic training. These subjects were followed from 6 months after accession into the military through the subsequent 4 yr. Follow-up was through military personnel records to determine retention and military hospital databases to determine subsequent hospitalizations during military service. Results: Military retention rates were slightly lower for those who suffered EHI during basic training, compared with those who did not (24% vs 30% at 4 yr. respectively). Outpatient EHI cases also had about 40% higher subsequent hospitalization rates in military hospitals than noncases during their continued military service, although these differences declined over time and diagnoses showed little relationship to EHI. EHI cases had higher rates of subsequent hospitalization for EH1, but the number was too small (five hospitalizations) to provide stable comparisons. Conclusion: Hospitalization for EHI is uncommon during subsequent military service after an initial episode during basic training, and occurrence of EHI during basic training has only a small impact on subsequent military retention and hospitalization.