Exertional heat illness: employment outcomes following military heat tolerance assessment

Background The UK Institute of Naval Medicine operates a Heat Illness Clinic (HIC) to assess service personnel for heat tolerance following Exertional Heat Illness (EHI). Aims This study aims to identify employment outcomes and EHI recurrence rates for those assessed. Methods A retrospective cohort study of patients seen in the HIC in 2019. Heat Tolerance Assessment (HTA) data were collected. Information on employment status and EHI recurrence were gathered from the clinical record. Results Data from 99 personnel were included; 78% were unrestricted at one year and 9% had been, or were likely to be, medically discharged due to EHI susceptibility. The remaining 13% had some level of ongoing limitation. Of the 84 personnel who were initially assessed as heat tolerant, 6 (7%) went on to have another episode of EHI and 3 of these (4%) were medically discharged. Of the 15 personnel who were initially assessed as heat intolerant, none have gone on to have a further EHI episode after 2 years and 6 were medically discharged. Eleven of the 99 personnel (11%) had their initial EHI on arduous selection activities for elite military units, and all these personnel were assessed as heat tolerant. Conclusions Most of those referred to the HIC are assessed and returned to unrestricted duty within 4 months. A minority of personnel have ongoing employment restrictions at 1 year. Arduous selection activities are high risk for EHI, regardless of HTA outcome. Those who are found to be heat tolerant on assessment remain at risk of EHI recurrence.