Whether sickle cell trait (SCT) carriers are at greater risk for exertional death has been a subject of intense debate.1 Large epidemiological studies in warfighters2 and athletes3 clearly show an increased risk for exercise-related sudden death in SCT carriers compared with non-SCT carriers.

The pathogenesis of exertional death in SCT carriers is unknown.4 However, the mechanisms initiating these adverse events could be parallel to the ones involved in the vaso-occlusion crises in sickle cell disease (SCD). Vaso-occlusion in patients with SCD involves haemorheological alterations, inflammation, vascular-adhesion processes and endothelial dysfunction.5 Comparisons of exercise responses between SCT carriers and non-SCT carriers demonstrated slightly decreased red blood cell deformability, increased …