Wilderness event medicine (WEM) can be defined as medical support for competitive events outside the usual scope of traditional emergency medical services (EMS). A more specific definition of WEM proposed in the medical literature is “a healthcare response at any discrete event with more than 200 persons located more than one hour from hospital treatment.”1 This definition is helpful in that, by including “healthcare response” in the out-of-hospital environment as a definitional characteristic of WEM, it emphasizes that WEM is at least in some ways a subgroup of wilderness EMS (WEMS). However, this definition does not take into account limited resources or specific skills and logistics (such as prolonged extrication times or difficulty in transport) that may be required in a more remote or austere setting. In 2015, Hawkins et al.² proposed a definition of WEMS that is also helpful in defining WEM:

Although some authors define WEMS [Wilderness Emergency Medical Services] as any situation that involves a minimum 1 to 2 hour transport time, this definition does not encompass every WEMS experience. There may be situations that require specialized medical care prior to extrication or transport even if the area is near a roadside, such as a patient injured on the hill at a ski resort or a hiker in a large urban nature preserve. Due to the specialized skills required to manage these patients, the inability to get supplies to the patient easily, or a complex extrication without the aid of an ambulance, these situations must also be considered wilderness. It is important to understand that WEMS is substantially more complex than the application of traditional medical training in a wilderness environment, and the indiscriminate application of traditional care and standards often proves to be dangerous to patients and/or providers in a wilderness setting.²

Specialized WEM skills that may be required to manage patients depend upon the race disciplines and venue, such as swiftwater rescue for river-based events, avalanche or snow rescue for alpine mountain events, or high angle rescue for climbing events. (Technical rescue interfaces such as these are all covered in more detail in Section 3 of this book.)

For the purposes of this textbook, we will define WEM as any wilderness or obstacle event that exceeds the usual capacity of traditional EMS either in distance or time to hospital, or in the skills and equipment required for expedient extrication.³ This definition encompasses the broad range of WEM coverage, which includes, but is not limited to, obstacle racing, adventure racing, mountain bike racing, trail running, and ultra-endurance events, as well as other events that occur beyond the typical scope of practice and subject matter expertise of urban, suburban, and even rural EMS.

Competitions such as ultra-running or adventure racing may be held in remote locations where well trained and highly skilled participants must be self-supported and navigate unmarked remote terrain for extended periods or long distances. These races have inherent risks related to location and environmental hazards, and may require very specialized WEMS skills such as search and rescue (SAR) skill sets or extrication and transport skill sets beyond standard medical training.

Obstacle course racing has attained great popularity and is an event type that may be located in less remote areas than other WEM events.⁴ Races such as the Spartan Race, Tough Mudder, and Warrior Dash had an estimated 1.5 million participants in 2014.⁵ These races typically are held on a predefined course wherein participants navigate multiple obstacles and challenges, such as crawling through mud pits, running through flames, risking electric shock, or leaping from a height into cold water.

Obstacle races tend to draw more novice athletes as compared to traditional adventure races, and the large number of participants has led to an associated increase in local emergency department (ED) and traditional EMS use. In a report from a single Tough Mudder event, the local ED reported treating 38 participants related to this single two-day event alone.⁶ ED volume alone may not reflect the
increased burden on the local emergency services infrastructure. This same series reported that “the burden on [traditional] EMS during this event was unanticipated. Reportedly, more than 100 advanced life support responses were activated, with many patients receiving initial treatment and then refusing transport.”⁶

The variability of disciplines, settings, number of participants, and distance or time from hospital for each event prevent development of standardized protocols for all WEM situations. However, procedural guidelines and principles can be developed, and are described below.

1. While an attraction for athletes to participate in obstacle and adventure races may be the challenge of the unknown, information provided to competitors prior to each event should include details such as specific disciplines, challenges that require special skills, the distance and/or expected duration of the event, and required gear for participant safety.

2. Nutrition and hydration sources should be made known, whether supplied by the event at established stations or required self-supported nutrition with racers being responsible for finding and detoxifying water (in which case maps indicating water sources should be provided).

3. With challenges that require a specific skill, such as those involving ropes/climbing, event organizers should be responsible for assessing the ability of participants to safely participate, as well as the quality and safety of their gear. All mandatory gear should be inspected.

4. Organizers of each event should be responsible for informing all staff, volunteers, and competitors of available emergent and non-emergent WEM procedures and other event support resources.

To prepare for providing appropriate medical care, WEM practitioners should know the most common injuries and illness that occur in the given environment of the race being covered. However, data found in the current medical literature regarding these conditions are extremely limited.

Information from endurance events with similar race disciplines (running, cycling, etc) held in urban settings can be used to predict WEM conditions.^{7,8,9,10,11,12,13} Musculoskeletal injuries, skin injuries, and dehydration are the most commonly encountered conditions treated in urban running events,^14,15 as well as in urban triathlon and cycling events, with orthopedic injuries and dehydration being the leading causes for competitor withdrawals and ambulance transfers.^16,17,18,19

The most commonly reported conditions in remote endurance events are similar to those in urban events of similar disciplines, yet also can vary greatly based on the characteristics and conditions of the race location. Temperature extremes or altitude may play a role in certain settings.^1,15,20,21 The most commonly encountered conditions in endurance events include blisters,^{9,10,11,12,22,23,24} nausea and vomiting,²⁵ respiratory illness,^22,24 orthopedic injuries,^12,23,26 and dehydration/heat illness.¹¹ Most conditions are not life-threatening, and fatalities are rare. For example, the estimated mortality rate in adventure racing is 1 per 100,000 racer-days.¹ Reported adventure racing fatalities are few: one due to drowning,^27,28 one due to hypothermia, and two due to head injuries.¹

Obstacle races are typically less remote. However, unique injuries and illness are encountered at these races. The popular press have reported injuries and fatalities due to heatstroke, spinal cord injury, and drowning.^29,30,31,32 There is very little scientific literature addressing medical conditions that occur in obstacle races. Greenberg et al.⁶ published a case series showing that obstacle racing participants experienced a high incidence of skin, soft tissue, and musculoskeletal injuries, as well as some unusual reported conditions of altered mental status, stroke, cardiac demand ischemia, near syncope, rhabdomyolysis, and myocarditis from electrical shock.³³ Electrical shock morbidity may be unusually common relative to other WEMS operational environments due to the use of electric shock challenges by at least one major race company (Tough Mudder). The Tough Mudder organization promises (“as our way of saying congratulations”) the delivery of 10,000 volts of electricity to racers via the Electroshock Therapy obstacle.³⁴ In a case series of five obstacle course patients published in Annals of Emergency Medicine in 2013, 80% of the injuries seen were associated with electrical obstacles.⁶

Travel to austere race sites carries all the inherent risk of travel to remote locations, and can result in systemic illness, such as traveler’s diarrhea or malaria. All competitors should have up-to-date immunizations appropriate for remote or foreign travel. There have been rare infectious diseases contracted at both adventure and obstacle races including Campylobacter infection,³⁵ leptospirosis,^{1,36,37,38,39} myiasis,^1,40 and rickettsia.^1,41

Preparation for individual considerations unique to each competitor, volunteer, and staff member should be attained by gathering information via medical questionnaires at the time of registration, well before the event itself begins.