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Medical complications and deaths in 21 and 56 km road race runners: a 4-year prospective study in 65 865 runners—SAFER study I
  1. Karen Schwabe1,
  2. Martin Schwellnus1,2,
  3. Wayne Derman1,2,
  4. Sonja Swanevelder3,
  5. Esme Jordaan3,4
  1. 1UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
  2. 2International Olympic Committee (IOC) Research Centre, University of Cape Town, Cape Town, South Africa
  3. 3Biostatistics Unit, Medical Research Council of South Africa, Cape Town, South Africa
  4. 4Department of Statistics and Population Studies, University of the Western Cape, Cape Town, South Africa
  1. Correspondence to Professor Martin P Schwellnus, UCT/MRC Research Unit for Exercise Science and Sports Medicine, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, 3rd Floor, Sports Science Institute of South Africa, Boundary Road, Newlands, Cape Town 7700, South Africa; mschwell{at}


Background Cardiac arrest and sudden death during distance-running events have been reported but other medical complications, including serious life-threatening complications have not been well described.

Objective To document the incidence and nature of medical complications during 21 and 56 km running races.

Design Prospective study.

Setting Two Oceans Marathon races (21 and 56 km races).

Participants 65 865 race starters (39 511—21 km runners, 26 354—56 km runners).

Methods Medical complications (defined as any runner requiring assessment by a doctor at the race medical facility or a local hospital on race day) were recorded in each of the 4 years of the study period. Complications were further subdivided into serious (potentially life-threatening) complications and deaths and were also analysed by system and final diagnosis.

Results In the 4 years, 545 medical complications were recorded, resulting in an overall incidence (per 1000 race starters) of 8.27. The incidence of serious (potentially life-threatening) medical complications was 0.56 (37 serious complications). Two deaths occurred in 21 km runners (incidence of 0.05). The most common specific medical complications were exercise-associated collapse (postural hypotension), dermatological conditions, musculoskeletal injuries and serious exercise-associated muscle cramping.

Conclusions The incidence of medical complications was higher in 56 km runners but sudden cardiac deaths only occurred in 21 km runners. Serious medical complications were as common in 21 km as in 56 km runners. Risk factors for medical complications need to be determined in 21 and 56 km runners to plan strategies to reduce the risk of adverse medical events in endurance runners.

  • Running
  • Epidemiology
  • Cardiovascular
  • Dehydration
  • Muscle Cramping

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