An estimated 300 million people worldwide have sickle cell trait (SCT). Although largely benign, SCT has been associated with exertional rhabdomyolysis and exercise-related sudden death in warfighters/athletes (WA). The National Collegiate Athletic Association's policy to confirm a student athlete's SCT status during their preparticipation medical examination prompted reaction from some organizations regarding the rationale and ethical justification of the policy. On September 26 and 27, 2011, a summit, composed of military and civilian experts in sports medicine and SCT, was convened at the Uniformed Services University in Bethesda, MD. The expert panel was charged with two objectives: 1) to provide specific recommendations to further mitigate the apparent risk with strenuous exercise in WA with SCT and 2) to develop clinical guidelines to identify, treat, and return to duty/play WA suspected to have incurred nonfatal sickle cell collapse. New terminology is introduced, areas of current controversy are explored, consensus recommendations for mitigating risk and managing the WA with SCT are reviewed, and important areas for future research are identified. Further research is needed before conclusions can be drawn regarding the etiology of the increased death rate observed in WA with SCT, and the possibility exists that SCT is a surrogate for as yet another contributing factor for the unexplained deaths.

Although largely benign, sickle cell trait (SCT) has been associated with exertion-related events, to include sudden death. In 2011, a summit on SCT introduced the term exercise collapse associated with SCT (ECAST). A series of ECAST deaths in military personnel in 2019 prompted reevaluation of current efforts and led to a second summit in October 2019 hosted by the Consortium for Health and Military Performance of the Uniformed Services University in Bethesda, MD. The goals were to (1) review current service policies on SCT screening, (2) develop draft procedural instructions for executing current policy on SCT within the Department of Defense, (3) develop draft clinical practice guidelines for management of ECAST, (4) establish a framework for education on SCT and ECAST, and (5) prepare a research agenda to address identified gaps.

Exertional heat stroke (EHS) is a leading cause of preventable morbidity and mortality among both athletes and warfighters. Since current evidence suggests that the history of a prior event is an important risk factor for an EHS event, sports medicine providers can find post-EHS return to play/duty (RTP/D) decisions challenging. Heat tolerance testing is a tool that can help with such decisions by exposing the subject to a given heat load under controlled conditions to assess the presence or absence of heat tolerance. This special communication explores the challenge of the RTP/D after an EHS event and the potential role of heat tolerance testing in making this clinical decision.

Objectives To characterise intrinsic and extrinsic (climatic) risks for mild and severe exertional heat illness (EHI) among first-year army enlistees. Methods We examined 337 786 soldiers who enlisted between 2012 and 2019. Survival models were used to predict incident EHI from intrinsic factors (demographics, healthcare utilisation, chronic conditions, body mass index (BMI), Army Physical Fitness Test (APFT), upper/lower respiratory tract infections (URTI and LRTI), skin and soft-tissue infections (SSTI), extrinsic factors (geographical region, daily mean Universal Thermal Climate Index (UTCI), wet bulb globe temperature (WBGT)) and interactions. Results There were 1390 cases of mild and 359 cases of severe EHI. Females had a higher risk for mild (adjusted OR (aOR) 1.78; 95% CI 1.57 to 2.02) but a lower risk for severe (aOR 0.61; 95% CI 0.38 to 0.87) EHI. Obesity was associated with severe EHI (aOR: 1.76; 95% CI 1.09 to 2.84) but not mild EHI (aOR: 1.03; 95% CI 0.76 to 1.39). URTI was associated with severe (aOR: 2.44; 95% CI 1.12 to 5.30) and mild (aOR 3.72, 95% CI 2.84 to 4.87) EHI, as were LRTI (severe, aOR: 11.40; 95% CI 6.09 to 21.32; mild, aOR 2.06; 95% CI 1.22 to 3.46), but not SSTI. UTCI outperformed WBGT in predicting EHI. Outside the Southern USA, EHI risk was elevated at lower UTCI. Associations varied over climate conditions and generally did not increase with climatic heat stress. Conclusions Respiratory infections were associated with the highest risk for EHI in soldiers. Risk mitigation strategies may include monitoring prevention and recovery from respiratory infections. Female sex and obesity may have different associated risks over climate conditions.

Exertion-related illness (ERI), despite aggressive efforts with both prevention and emergency action planning, continues to be a considerable threat to both athletes and warfighters. Numerous case reports and series have served to elucidate risk factors, which have in turn become the focus of prevention strategies. While this approach has assisted in mitigating athlete risk, recent institutional guidance has identified the need for greater protection of athletes by accountability of training programs and the recognition of periods of distinct athlete vulnerability. These recommendations, in addition to observations from lessons learned from the aforementioned cluster reports of ERI, have a strong call-out for the role of leadership as both a culprit for injury and a potential mechanism for prevention. This commentary introduces a leader-follower framework and explores this model in the evolution of ERI and offers recommendations as to how we move forward toward making progress in prevention.