a b s t r a c t

Objective: Alaska’s 1049-mile Iditarod Trail Sled Dog Race is the world’s longest sled dog race and the flagship event in the sport of sled dog racing. Race conditions are typically harsh. Physicians are not officially enlisted to care for human competitors. Instead, medical needs are met through an informal system of volunteers, local health care providers, and a fleet of bush planes. The goals of this study were to identify the types of human injury and illness experienced and the methods by which these conditions are treated.

Methods: Competitors in the 2010 Iditarod were surveyed at the halfway point and at the finish of the race. Survey elements included specific types and frequencies of injuries and illnesses, and the sources and types of treatments.

Results: Seventy-one teams entered the race, 62 participated in the halfway point survey, and 55 completed the finish line survey. Ninety-nine injuries were reported by 42 (68%) of the survey respondents. Frostbite was the most common injury, occurring in 20 (31%) of the respondents. Musculoskeletal pain was also commonly reported. Two mushers sustained Closed head injuries, with 1 requiring evacuation. Twenty-three mushers (37%) reported an acute nontraumatic condition, most frequently an upper respiratory infection (9 respon- dents). In most instances, medical conditions were self-managed. Race veterinarians and support staff, as well as local village clinicians, administered the majority of care, typically wound care or oral antibiotic administration. Conclusions: Most injuries and illnesses sustained by mushers in the Iditarod are minor and self-treatable. Life- threatening conditions are rare, and the need for an organized medical care system seems low.

(C) 2014

Introduction

The Iditarod Trail Sled Dog Race is an extreme, cold weather endurance contest. This annual event typically draws a field of between 70 and 95 teams consisting of a human “musher” and 16 sled dogs. Teams race around the clock, stopping for brief rest breaks and meals every 6 to 10 hours plus 1 longer, 24-hour break at 1 of the 21 check- points along the trail. Each checkpoint is staffed with race officials as well as a team of veterinarians. No assistance is provided to these teams during the competition, unless an unexpected and potentially serious event develops. Teams may spend 2 weeks on the trail before finishing. Veterinary research has been conducted on the canine athletes that compete in this race, but considerably less research has been published on the human competitors despite this event offering an excellent opportunity to study the effects of extreme climates on endurance athletes. Published studies on human competitors in this annual event have primarily focused on the functional traits of mushers, especially the stressful effects of Sleep deprivation, physical

? The authors have no commercial associations or sources of support that might pose a conflict of interest. This study did not receive external funding. All authors have made substantive contributions to the study, and all authors endorse the data and conclusions. Reprints are not available from the authors.

* Corresponding author. Tel.: +1 207 662 1452; fax: +1 207 662 7025.

E-mail address: [email protected] (G.L. Higgins).

exertion, and cold exposure on behavior, metabolism, body mass, and hormonal physiology [1-5]. Although anecdotal reports suggest that physical injuries and illness do indeed occur during the Iditarod race, we could identify no systematic published data specifically ad- dressing this issue. Our investigation is meant to serve this purpose and identify the sources of treatment used.

The primary objective of this study was to contemporaneously survey the mushers competing in the 2010 Iditarod Trail Sled Dog Race, both at the midpoint and at the completion of the event, to determine the frequency, nature, and severity of the injuries and illnesses sustained. In addition, we were interested in identifying the sources of medical care used by the competitors when needed. Finally, we were interested in examining in detail any emergent medical evacuations or search-and-rescue operations activated during this race, with focus on the equipment and personnel involved and the specific circumstances surrounding these operations.

Methods

To determine the scope and frequency of injury and illness en- countered by Iditarod mushers, competitors were asked to voluntarily respond to a survey. Identical surveys were administered during the race at the halfway point as well as after the race at the finish line in Nome. This was done to improve data accuracy given the length of

http://dx.doi.org/10.1016/j.ajem.2014.02.018

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the event. The survey was administered by 2 emergency physicians who are both veteran Iditarod competitors. Institutional review board exemption was awarded by the Maine Medical Center Research Insti- tute, Portland, ME.

The survey asked mushers to identify any injuries or medical illnesses that were experienced during the race and to describe these conditions. Injuries were categorized as either orthopedic or non- orthopedic traumatic. Respondents were then asked to describe whether each condition was acute or related to a preexisting con- dition and to rate the impact each condition had on their ability to compete in the race. This rating was done on a 1-5 scale, with 1 representing no impact and 5 representing a condition that led to the musher withdrawing from the race. Lastly, respondents were asked to identify any and all sources of treatment used for each condition, including self-administerED treatments.

Data were categorized by race bib number, and conditions re- ported at the halfway point survey were not counted a second time at the finish survey. Data were entered into a Microsoft Excel (Microsoft Corp, Redmond, WA) spreadsheet program for organization and analysis. Summated data are presented as numbers and percentages.

Results

Seventy-one competitors entered the race, and 55 (77%) reached the finish line. Overall, at least 1 survey (halfway point or finish line) was completed by 62 (87%) of the 71 competitors. Of the 55 finishers, 45 (82%) completed both halfway and finish line surveys. An ad- ditional 4 finishers completed the survey at the finish line only, yielding an overall response rate of 49 (89%) of 55 finishers. All survey respondents, whether they finished the race or not, are included in the data provided. In addition, each injury was counted separately, even if a musher sustained 2 or more injuries in a single accident or, in the case of frostbite, if 2 different locations on the body were involved.

Overall, 99 injuries were reported by 42 (68%) of the survey respondents (Table 1). The most injuries reported by a single com- petitor were 5. When grouped together, orthopedic conditions com- prised the most common acute injury type, accounting for 30 (30%) of

99 injuries. Frostbite was also a common injury, representing 20 (20%) of the reported injuries. Sixteen (80%) of 20 frostbite injuries were to the hands and feet. Other acute nonorthopedic traumatic injuries comprised 18 (18%) of the reported injuries. Most were minor and did not have a significant or race-ending impact on the musher. However, 2 mushers sustained closed head injuries, with 1 also sustaining metacarpal fractures and requiring evacuation. This incident is discussed in further detail below.

Twenty-three mushers (37%) reported a total of 28 illnesses (Table 2). Twenty-one (75%) of the illnesses were acute. Upper res- piratory infection was most common and was reported by 9 (15%) of 62 respondents. Six respondents (10%) reported chronic illness, with asthma and Insulin-dependent diabetes each being reported by 2 mushers. Notably, these mushers all rated these chronic diseases as having only minor impact on their ability to compete in the race.

Overall, the impact of injury or illness on the mushers’ ability to compete in the race was deemed to be minor (Figs. 1 and 2). However, the injuries that were reported as having a significant impact on mushers’ ability to compete were knee sprains [2], frostbite [2], upper extremity contusion [1], thumb pain [1], finger splits [1], and muscle cramps [1]. The 2 illnesses reported as having a severe impact were both upper Respiratory infections. A single musher sustained 2 injuries that were each classified as race ending.

For both injuries and illnesses, the majority of care and treatment was self-administered. Other sources of care included race veterinar- ians (6 instances of care), physicians (5 instances), fellow competitors (4 instances), other race personnel (2 instances), village health aides (1 instance), and dentists (1 instance of care after the race finish). The veterinarians assisted in the treatment of 4 injuries and 2 illnesses.

Table 1

Injuries sustained by the competitors of the 2010 Iditarod (n = 62 respondents)

Acute orthopedic injuries 30 (30%)

Acute neck/back pain 8

Sore hands/feet 7

Acute knee injury 6

muscle strain/tear 5

Ankle sprain 2

Acute shoulder pain 1

Hand fracture 1

Frostbite 20 (20%)

Frostbite, hands 9

Frostbite, feet 7

Frostbite, face/nose 4

Acute traumatic injuries 18 (18%)

Contusion/abrasion, upper extremity 6

Hand laceration 3

Contusion/abrasion, lower extremity 2

closed head injury 2

Minor abrasions, not to extremity 2

Nasal fracture 1

Chipped teeth 1

Hot water burn 1

Diplopia (after head injury) 1

Acute or chronic back/neck/extremity pain 14 (14%)

Other acute exposure, related injuries 13 (13%)

Numbness, fingers/toes 6

Finger splits 6

Frozen corneas 1

Miscellaneous injuries 4 (4%)

Muscle cramps 2

Groin pain 1

Skin chafing 1

Total 99

Treatments provided by the veterinarians included antibiotics and wound closure with sutures.

A single medical evacuation was required. This musher sustained a significant closed head injury and a fractured hand. He was initially found and treated by a fellow competitor who happened to be a medical student. Other competitors were able to notify race officials at the nearest checkpoint. A privately owned ski plane capable of landing in the tight mountainous terrain was in the area. The pilot ferried the injured musher to the nearest checkpoint, where he was transferred to one of the Iditarod’s ski planes and flown directly to Anchorage. Fortunately, evaluation at the receiving hospital revealed no signif- icant intracranial injuries.

Discussion

Alaska’s 1049-mile Iditarod Trail Sled Dog Race is the world’s longest sled dog race and the flagship event in the sport of sled dog racing. The course originates near Anchorage, crosses the Alaska

Table 2

Illnesses sustained by the competitors of the 2010 Iditarod (n = 62 respondents)

Acute illness 21 (75%)

Respiratory infection 9

Extreme fatigue 3

Nausea/Vomiting 3

Diarrhea 2

Dehydration 2

Dental pain/infection 1

Syncope 1

Chronic illness 6 (21%)

Asthma/Reactive airways disease 2

Insulin-dependent diabetes 2

Hematologic malignancy 1

Chronic muscle cramping disorder 1

Miscellaneous illness 1 (4%)

Lower extremity edema 1

Total 28

Fig. 1. Number of reported injuries by severity.

Mountain Range, traverses the desolate interior of the state, and then follows the Yukon River before crossing a smaller mountain range and following the Bering Sea coast to Nome (Fig. 3). Conditions are variable but can be severe, with temperatures reaching lows of -51?C and wind speeds recorded in excess of 128 km/h along the trail (personal experience and knowledge of the first author J.W.G., who has competed in this event).

Our survey data suggest that most mushers incur some type of acute injury while competing in the Iditarod. These injuries can be assigned to 3 general categories: orthopedic, exposure-related, and nonorthopedic trauma. Studies of traumatic conditions in other wilderness activities have been published, and these reports suggest that sprains, strains, and soft tissue injuries are the most common injuries [6,7]. Consistent with this, nearly half (48%) of the injuries reported in our survey were orthopedic or nonorthopedic trauma in nature. Notably absent from the list of injuries reported in the survey were bite wounds, despite the presence of more than 1000 dogs during the event.

Based on the reported impact these injuries had on participants’ ability to compete, it appears that most injuries were minor. Only 4 respondents rated orthopedic injuries or nonorthopedic trauma as having a severe impact on their performance. In part, this may be explained by the high level of both experience and physical fitness of the mushers, although this study did not examine the effect of these variables. Interestingly, very few mushers wear any kind of dedicated protective equipment such as helmets or padding. Although not part of our survey, one musher in the 2010 Iditarod wore hockey pads over his shoulders and upper body during the first part of the race when the trail crosses the Alaska Mountain Range. Otherwise, most mushers simply wear highly insulated clothing in- cluding face masks and goggles depending on conditions. This pro-

Fig. 2. Number of reported illnesses by severity.

bably provides some degree of protection from trauma by virtue of the layers of soft insulation.

Despite the advanced cold weather clothing, exposure-related injuries were also very common in our study population, comprising 1 of every 3 reported injuries. Not surprisingly, most of these injuries were to the hands and feet. Similar to mountaineering and polar exploration, the Iditarod and other ultralong-distance sled dog races require participants to spend extended periods of time in subfreez- ing conditions. Adding to the challenge is sleep deprivation and the degree of physical exertion required of the single human member of each team. All dog care and feeding, as well as equipment main- tenance, are the sole responsibility of the musher. Consequently, hands and feet appear especially vulnerable. Presumably, painful splits in fingertips and paresthesias of fingers and toes are also related to cold weather exposure based on the anecdotal reports of the mushers.

Maintaining adequate hydration is an important aspect of any athletic endeavor, and this is a major challenge for Iditarod mushers given the difficulties in preventing water and electrolyte solutions from freezing while on the trail. There are numerous adverse con- sequences of dehydration, including an increased risk of exposure- related injury and muscle cramping. However, only a single participant reported muscle cramping as an injury.

Despite sleep deprivation, physiologic stress, cold weather, lack of running water, and suboptimal sanitation along the trail and the fact that mushers often prepare their own food near the raw meats and fats being fed to the dogs, illness was significantly less prevalent than injury in our survey. Only 21 acute illnesses were reported. Predictably, respiratory and gastrointestinal infections comprised 67% of acute illness. Interestingly, only 3 participants reported ex- treme fatigue and 2 participants reported dehydration as illnesses. Overall, the impact of acute illness on respondents’ ability to compete in the race seemed mostly minor.

Most injuries and illnesses were self-treated. Given the minor impact most conditions had on the mushers, this is not surprising. However, the lack of a formal medical system to care for mushers along the race trail also probably accounted for this observation. In addition, although not a part of the mandatory equipment required by Iditarod rules, most mushers carry some sort of first-aid kit that often includes bandages, tape, ACE wraps, and basic over-the-counter medications (personal experience and knowledge of the first author J.W.G., who has competed in this event).

The Iditarod has a large veterinary staff, but no dedicated physi- cians. Some race volunteers and officials have varying degrees of medical training ranging from emergency medical technicians to emergency physicians with wilderness medicine experience. How- ever, they are not dedicated medical personnel, are often not licensed to practice in Alaska, and are usually serving other roles. They provide medical care on a coincidental basis as “Good Samaratins.” The only licensed and trained medical providers along the race trail are the health care workers in the Alaska Native villages the race passes through. The larger villages often have a physician assistant or nurse practitioner, but smaller villages usually only have a village health aide with training equivalent to an intermediate emergency medical technician.

In contrast, each of the Iditarod’s 21 checkpoints has a team of up to 6 veterinarians who are available around the clock while teams are passing through. They are well equipped to manage a large variety of emergency veterinary medical conditions. Supplies include intravenous fluids, antibiotics, anesthetics, and wound care equip- ment. Most of these supplies are actually labeled for human use. Given the paucity of medical providers relative to veterinarians, it is not surprising that the veterinarians provide as much musher care as physicians and village health aides combined. Based on our survey data, it appears that most of the care provided by veterinarians included administering antibiotics for respiratory and soft tissue

Fig. 3. Route of the Iditarod Trail Sled Dog Race.

infections and performing wound care. These would likely be covered under Alaska’s Good Samaritan law [8].

As illustrated by the single case of a medical evacuation that was required during the 2010 Iditarod, situations when mushers sustain more significant and potentially life-threatening injuries or illness are much less common. There is no way to predict when or where such events might occur, but when they do, the race relies on its very well organized logistics system. At the center of this is the race’s network of ski planes and snowmobiles, which is linked by satellite telephones and pagers to each checkpoint and to the race headquarters. Checkpoints are staffed with local residents and veteran mushers who monitor the arrival and departure of teams and preemptively initiate searches if a team is overdue. However, in most cases, including the incident we describe, initial assistance is provided by other mushers or some of the few spectators who are along the trail (personal experience and knowledge of the first author J.W.G., who has competed in this event). As illustrated by the emergency evacuation we report, there is excellent cooperation between these resources, allowing quick transport of a severely injured musher to definitive medical care. In other years, this system has served other mushers with various severe illnesses, hypother-

mia, and carbon monoxide poisoning [9]. That there have been no human fatalities in the race’s 41-year history speaks to the effec- tiveness of the existing system of care.

Limitations

Our study has several limitations that deserve consideration. This was an observational study based on results of a survey and, con- sequently, is at risk for recall bias on the part of the respondents. The fatigue and stress experienced by the mushers could well have in- creased the chances of forgotten or poorly reported illness or injury. Although we attempted to mitigate this by surveying mushers twice during the race, the likelihood of bias remains.

We did not attempt to standardize definitions or objectively verify illness or injury. Mushers have varying degrees of race experience and physical fitness. This likely influences their perception of the severity of injuries or illnesses occurring during the event. The reports of fatigue and dehydration are probably representative of this.

We only examined a single running of the race. Although a smaller sample size is an obvious result of this limitation, the much larger and possibly less apparent problem with only sampling a single

year is that the weather and trail conditions are highly variable. During the 2010 Iditarod, the weather was very cold, reaching -46?C at the halfway point while surveys were being conducted. How- ever, the snow conditions were generally very good and wind storms were infrequent. In other years, temperatures rarely drop below - 20?C, wind conditions can be challenging, or snow conditions are poor, making the terrain difficult to navigate. Such variations in the weather patterns likely will impact the prevalence of various types of injury and illness.

Conclusion

Our investigation adds to the collective understanding of the frequency and types of injuries and illnesses that can be predicted to occur during extreme, cold weather endurance events. This type of information will potentially allow participants to better prepare for, and possibly prevent, injury and illness during the competition. Race organizers and medical providers can use these observations to more effectively implement the type of medical supplies, services, and rescue resources that will be required to minimize risk.

Despite predictably harsh conditions, most injuries and illnesses sustained by mushers in the Iditarod are minor and self-treatable. Life-

threatening conditions are rare, and the need for a more organized medical care system seems low. Observations resulting from this survey may be applicable to other outdoor extreme endurance sporting events.

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