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Competitive Sports: Section Articles

Common Ultramarathon Injuries and Illnesses

Race Day Management

Khodaee, Morteza MD, MPH1; Ansari, Majid MD2

Author Information
doi: 10.1249/JSR.0b013e318272c34b
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Ultramarathon refers to any foot race longer than the standard 42.195 km marathon. Ultramarathon is gaining popularity among nonelite athletes (48). There are more than fifty 161-km ultramarathon races in North America (16). Although there are similarities between marathons and ultramarathons, the athletic population, common injuries, and illnesses are quite different (16,20,41). Average ultramarathoners are in their 40s and have more running experience compared with average marathoners (16,41). In contrast to marathon runners, ultramarathon participants usually complete longer training programs with better preparation. Ultramarathon runners are usually a group of highly motivated, goal-oriented, and self-coached athletes who like to push their limits. The physical and psychological demands of ultramarathons are enormous. Runners must often navigate long distances over a variety of terrain in temperatures ranging from below freezing point to above 40°C. Because the ultramarathoners must persevere at a physically demanding task for an extended period of time, psychological factors have a profound impact on their performances. Different degrees of alteration in mental status are common during ultramarathons.

Medical coverage of ultramarathons is provided usually by a medical team consisting of race director(s) and multiple volunteers. Our understanding and knowledge of the common injuries and illnesses in ultramarathons is limited. Despite the fact that most injuries encountered by the runners during an ultramarathon race are minor (23), they still can compromise the results of the injured runners. For the majority of runners, reaching the finish line is the ultimate goal. Thus management of race day injuries in order to help runners finish the race while minimizing the risk of further injuries or illnesses can be challenging. In this article, we will review race day management of common injuries and illnesses encountered in ultramarathons.

Musculoskeletal Injuries

Musculoskeletal (MSK) injuries are common during ultramarathons. MSK injuries are most commonly seen as the result of overuse in lower extremities predominantly below the knee (9,25). If a runner persists on completing the race in spite of the pain, cryotherapy (ice) and various taping techniques can be offered as possible alternatives for temporary pain relief (SOR C) (5). Judicial use of acetaminophen also can enable the runners to continue with the race. Due to the potential risk of renal and gastrointestinal (GI) complications, use of oral nonsteroidal anti-inflammatory drugs (NSAIDs) during the race is not recommended.

Patellofemoral Pain Syndrome

Patellofemoral pain syndrome (PFPS) is the most common reported running injury with a higher prevalence among female runners (10,43). While the exact incidence of PFPS among ultramarathon runners is unknown, a few retrospective studies reported an incidence of 7.2% to 24.3% (9,16,33). The prevalence of PFPS during ultramarathon races has been reported from 7.4% to 15.6% (25).Various taping techniques and patellar braces have been suggested for prevention of PFPS during the race (SOR C) (5,19). Although an increase of 5% to 10% in the running pace, with subsequent shorter steps, may decrease the pain in some runners, such changes in cadence may have an undesirable effect on the runners’ performance (3).

Iliotibial Band Friction Syndrome

As the most common cause of lateral knee pain in runners, the iliotibial band (ITB) friction syndrome has an incidence of about 1.6% to 12% (42,43). It has a self-reported 1-year prevalence of 7.3% among participants of two 161-km ultramarathons (16). The ITB is a lateral stabilizer of the knee joint (8,42). There is a proposed impingement zone at 30° of knee flexion. Running uphill, downhill, and at slower paces, which is inherent in ultramarathons, may lead to a higher fraction of time in this zone (SOR C) (42). The pain is elicited usually after a fixed distance, after repetitive flexion and extension of the knee, or by holding the knee in 30° of knee flexion. It is relieved when the knee is held at full extension (8,14,42). As the problem progresses, the onset of symptoms begins earlier during the course of running (8,42). Acetaminophen, cryotherapy, myofascial release techniques, foam roller, and shortening the stride length may be helpful in alleviation of the symptoms during the multistage races (SOR C) (42). Long rest and immobility in aid stations should be discouraged to prevent worsening pain and tightness in ITB.

Medial Tibial Stress Syndrome

Medial tibial stress syndrome (MTSS) is a common running injury observed in about 5% of runners with a higher prevalence among men (43). The prevalence of MTSS ranges from 7.8% to 11.1% during ultramarathon races (25). Most of the existing data on the prevalence of MTSS comes from cross-sectional self-report studies (9,25,43). Differentiating this almost benign condition from more important conditions, such as stress fractures and compartment syndrome, may have a dramatic effect on return to race decisions. Most of the runners adapt to a slower running speed to decrease the pain during the race. The diagnosis of MTSS in the settings of new onset shin pain during the race should be a diagnosis of exclusion. In less severe cases, cryotherapy, stretching, and topical analgesics may be of some value during the race intervals

Stress Fractures

Stress fractures are common among ultramarathoners. A survey study of the participants of two 161-km ultramarathons revealed a self-report of a 9.5% stress fracture rate in the previous year (16). In this study, foot, tibia, and femur were the most common stress fracture sites (4.6%, 3.8%, and 1.1%, respectively) (16). The repetitive stress of running without proper rest may lead to a spectrum of pathologic bone responses from stress reactions (microfracture) to stress fractures (frank cortical disruption). The huge increase in running distance during the race compared with typical training programs puts ultramarathon runners in a much higher risk of developing stress fractures compared with the shorter distance running events. Diagnosis during the race is based on physical examination, which may manifest focal tenderness, swelling, and warmth (27). Even if access to a local clinical facility is available, plain radiography is not an appropriate modality for the diagnosis of stress fracture during or after the race. Cortical reactions may take up to 5 wk to become evident in plain radiographs. High clinical suspicion of stress fracture during a race warrants the termination of the race for the runner. Conservative on-site management includes immobilization, cryotherapy, and acetaminophen. Balanced diet to prevent weight loss, smoking cessation, daily intake of 1,500 to 2,000 mg of calcium and supplemental vitamin D, arch supports (especially if pes planus is present), and optimizing the training routines may prevent stress fractures (SOR C) (27). A 10% reduction in stride length and an increase in the running cadence may decrease the risk of tibial stress fracture by decreasing the tibial strain forces (7,15).

Chronic Exertional Compartment Syndrome

The majority of diagnoses related to leg pain in runners can be attributed to overuse injuries. Following MTSS, chronic exertional compartment syndrome (CECS) is the second most common causes of chronic leg pain in athletes (12). The exact incidence of acute on chronic exertional compartment syndrome among ultramarathoners is unknown, but it seems to be rare (30). Pain usually instantly disappears following cessation of the run and some rest with no permanent sequelae in the compartment. However, in rare cases, if the exertion continues despite the pain, acute compartment syndrome may occur (12). Physical examination during or postrace may reveal a tense or tender involved compartment. Any runners with continued pain in their lower leg despite rest should be transferred to the emergency department to rule out acute on chronic exertional compartment syndrome (30). Other less common symptoms and signs of an acute compartment syndrome like paresthesia, pallor, paralysis, and pulselessness may be present. Delay in diagnosis and treatment may cause significant consequences. Compartment fasciotomy may be warranted if the symptoms do not resolve with conservative management (30,45).

Exercise-Associated Muscle Cramp

Exercise-associated muscle cramp (EAMC) is one of the most common conditions faced by an ultramarathon runner. It is reported to be the most common (56.5%) cause of premature race termination in a 250-km off-road ultramarathon (23). In a survey study, 5% of 161-km ultramarathon runners reported muscle cramp as their main reason to drop out of the race (16). It is characterized by painful involuntary spasms during or immediately after exercise, which occur mainly in gastroc/soleus complex, hamstrings, or quadriceps muscles. Despite the common belief among the athletes and coaches, there is limited evidence to support heat, dehydration, and electrolyte imbalance as the predisposing factors of EAMC (13, 35, 36). Neuromuscular fatigue and increased excitatory activity of neuromuscular units have been proposed as the possible mechanisms (13). In ultramarathon runners, increased relative exercise intensity, previous history of EAMC, and preexisting muscular damage are among the risk factors for EAMC (35,36). The role of hyponatremia remains to be more clarified in future research (13). Acute EAMC can be managed by rest, various massage techniques, and passive stretching of the affected muscles. In cases of identified risk factors for other specific diagnoses, a targeted work-up is warranted. “Salty sweaters” (white, salt steaks on clothing, or skin) often claim that salt or sodium supplements during a race may alleviate cramping.

Sesamoid Stress Injuries

The sesamoid complex is located centrally at the plantar side of the first metatarsal head, lying within the medial and lateral heads of flexor hallucis brevis, while also receiving attachments from abductor and adductor hallucis tendons (2). It normally transfers up to 50% of body weight, but this load can reach >300% during the run (push-off). The repetitive nature of running, and the large magnitude of these forces, can make the sesamoid complex prone to various pathologies (e.g., sesamoiditis, osteochondritis, acute, and stress fractures). Sesamoid disorders account for 1.2% of running injuries (2). Prevalence of sesamoid stress injuries during ultramarathons is unknown. Sesamoiditis is a painful condition of the sesamoid complex due to repetitive stress with no radiographic findings. Crepitus, tenderness, and pain on extension of the first metatarsophalangeal joint are the main clinical findings. Sesamoid stress fracture is the most common pathology of the sesamoid complex, which typically involves the tibial sesamoid (2,21). Runners with clinically suspicious findings should be referred nonurgently to their primary care physicians for further work-ups after the race.

Meniscal Injuries

Five percent of running injuries presenting to a large sports medicine center were identified as meniscal tears (43). With an increase in the average age of ultramarathon runners, the rate of meniscal injuries may be on the rise (10). The prevalence of acute meniscal injuries during ultramarathons is unknown. In one magnetic resonance imaging study on 22 asymptomatic nonprofessional athletes, running a marathon race did not cause major changes to the menisci (34). Whether running an ultramarathon increases the risk of an acute meniscal injury in runners over the age of 40 years is controversial. The decision on dropping out or continuing an ultramarathon race in a runner with a suspected acute meniscal tear depends on the runner’s symptoms and desire to complete the race, but mechanical symptoms such as locking or catching may predispose runners to further injury and warrant disqualification.

Plantar Fasciitis

Plantar fasciitis accounts for about 8% of all running injuries and is more common in male runners (21,43). Self-reported 1-year prevalence of plantar fasciitis was 9.6% among ultramarathoners in one survey study (16). Pain and tenderness over the medial plantar calcaneal tubercle is diagnostic in most cases, although differentiation from a calcaneal stress fracture can be difficult in some cases (6). Cryotherapy, topical analgesic preparations, and acetaminophen may temporarily alleviate the pain. Plantar fascia rupture, presenting sometimes as a sudden increase in pain while running combined with a palpable defect, can end a race.

Lower Extremity and Achilles Tendinopathies

Tendinopathy refers to a wide spectrum of disorders ranging from tendinitis (acute tendon inflammation) to tendinosis (chronic tendon degeneration) to tenosynovitis (tendon sheath inflammation) to partial and complete tendon ruptures (47). Tendinopathies of the lower extremities are relatively common in runners. However the exact prevalence of tendinopathies among ultramarathon runners is unknown. Achilles, patellar, peroneal, anterior, and posterior tibial tendinopathies are most common (39). Rupture or partial rupture presenting as a defect or significant increase in pain may prevent a runner from completing a race.

Achilles tendinopathy

In one study the self-reported 1-year prevalence of Achilles tendinopathy among ultramarathoners was 11.5% (16). Its prevalence during ultramarathons ranges from 2% to 18.5% (25). Noninsertional, or midportion tendinopathy (MPT) is the most common type, occurring in the avascular zone 2–6 cm proximal to the insertion of the tendon into the calcaneus (6,10,47). The patient has a gradual onset of pain which deteriorates after uphill running or sprinting (toe-running).

Patellar tendinopathy and rupture

Taunton et al. (43) reported that 4.8% of patients presenting to a sports medicine clinic had patellar tendinopathy. The exact prevalence of patellar tendinopathy among ultramarathon runners is unknown as most epidemiologic studies have knee pain as their self-reported diagnosis (16,28,33,46). Diagnosis is made usually by history and physical examination (point tenderness). Rupture may occur with a history of tendinopathy and an increase in intensity or environmental and terrain challenges of ultramarathons.

Posterior tibial tendinopathy

Posterior tibial tendon (PTT) stabilizes the medial longitudinal arch. In one retrospective study, 0.55% of patients presenting to a sports medicine clinic had posterior tibial injury (43). PTT dysfunction can stress the ligaments of hindfoot and midfoot, resulting in a painful acquired flatfooted deformity. In severe cases, medial ankle instability may occur due to deltoid ligament injury (39,47). An acute increase in pain or drop in the medial arch warrants discontinuing the race.

Anterior tibial tendinopathy

Anterior tibial tendon (ATT) is the main foot dorsiflexor. ATT dysfunction or rupture is uncommon and results in foot drop and a slapping gait (39). It is more common among long distance runner over the age of 45 years (39). If gait or running form is affected in a way that further injury is a concern, it needs to be discussed with runners who wish to complete events.

Peroneal tendinopathy

Peroneal tendon injuries (tendinopathy, subluxation, and ruptures) are uncommon. Only 0.65% of patients presenting to a sports medicine clinic had peroneal tendinopathy (43). Persistent lateral ankle pain and chronic lateral ankle instability are linked usually to the peroneal tendinopathy. Running on uneven ground and muscle fatigue may lead to peroneal tendon problems in ultrarunners. New snapping symptoms or acute lateral pain posterior to the lateral malleolus may warrant subluxation or longitudinal tendon tear and may require a runner to withdraw from a race.

GI Problems

Ultramarathon runners show various GI symptoms from diarrhea to GI bleeding that can have a negative effect on their performances (44). The causes of GI symptoms in runners may include the mechanical injury during running, inappropriate calorie and fluid consumption, changes in GI motility, visceral vasoconstriction (reducing splanchnic blood flow) medication influences on absorption and secretion, endotoxins (Gram-negative lipopolysaccharides), neuroendocrine alterations, and altered hemodynamics of the GI system (38). GI symptoms are more common in longer ultraendurance events and have been reported in up to 85% of ultramarathoners (16,38,44).

Common upper GI tract problems in ultramarathoners are nausea, vomiting, gastroesophageal reflux disease (GERD), and peptic ulcer disease. In a survey study of 161-km ultramarathoners, the main reason to drop out of the race was nausea or vomiting (23%), which was equally prevalent among finishers and nonfinishers (16). Nausea or vomiting was the second subjective performance-influencing factor among the finishers (16). Oral ondansetron can effectively reduce nausea and vomiting during the ultramarathon race in otherwise stable runners (authors’ experience). GERD is more common among runners. Use of NSAIDs during the race increases the risk of upper GI problems. Individualizing hydration and calorie needs to minimize symptoms during training can decrease symptoms on race day.

Lower GI tract problems (diarrhea, bloating, urge to pass stool, abdominal cramps, and blood in stool) are more common among endurance runners ranging from 37% to 71% (38,49). Predisposing factors include female sex, lower age, history of abdominal surgery, irritable bowel syndrome, lactase deficiency, and dehydration (49). Frank GI bleeding is encountered rarely in runners, although minor bleeding is quite common (38,44). The source of bleeding is the upper GI tract in most cases. A 3-d course of a proton pump inhibitor prior to a race has been reported to decrease the risk of minor GI bleeding in ultramarathon runners (44).

In a recent survey study, more carbohydrate intake during the race correlated with reduced nausea and flatulence and better race performance among ultraendurance athletes (29). American College of Sports Medicine recommends a preexercise meal or snack relatively high in carbohydrate and low in fat and fiber to facilitate gastric emptying and minimize GI distress (31). Proper rehydration with appropriate fluid and electrolytes is essential in the management of GI tract problems. Prerace training using nude weight, urine output and color, and monitoring performance can help athletes estimate fluid and calorie needs.

Environmental Illness

Ultramarathons are held in a variety of geographic locations with some extreme climate changes (e.g., heat, cold, altitude, lightning, and thunder).

Altitude Illness

Altitude illness occurs at the elevation of 2,500 m or above. Risk factors for the development of altitude illness are rapid ascent, living at a low altitude, intense physical exertion, young age, and history of altitude illness.

Acute mountain sickness

It is the most common presentation of altitude illness and is defined by the presence of headache and at least one additional symptom (anorexia, nausea, vomiting, dizziness, fatigue, and difficulty sleeping) within 6 to 12 h of gaining altitude (37). Significant exertion on race day without prior acclimatization increases risk for altitude illness. Physical examination is usually unremarkable. NSAIDs and acetaminophen are effective agents for mild headache, and athletes must be monitored carefully for significant or worsening symptoms that preclude disqualification for safety reasons. Acute mountain sickness (AMS) occurs on a spectrum with high altitude cerebral edema (HACE), so severe headache and any confusion following AMS symptoms should be assumed to be HACE until proven otherwise.

High altitude pulmonary edema

Runners with high altitude pulmonary edema (HAPE) usually complain of shortness of breath at rest, cough, decreased exercise performance, chest pain, tightness, or congestion. Physical examination may reveal low oxygen saturation, crackles or wheezing, central cyanosis, tachypnea, and tachycardia. Supplemental oxygen, relative rest, and descent are accepted measures for treatment of HAPE. Prophylaxis with salmeterol, nifedipine, dexamethasone, or phosphodiesterase-5 inhibitors (e.g., sildenafil) may reduce the incidence of HAPE (SOR B).


HACE is the end stage of AMS defined by altered mental status or ataxia in a person with AMS or HAPE. HACE can progress rapidly to death. Rapid descent and transfer to the hospital are advised (37). Acetazolamide and dexamethasone can be used for prevention and treatment of HACE (SOR B), and oxygen should be used if available.

Acclimatization and prevention of altitude illness

Runners who live in lower altitude should arrive at the higher altitudes at least 2 wk before the race if they wish to achieve proper acclimatization. One evening spent at a lower altitude such as 1,500 m (e.g., Denver) can reduce the incidence of AMS by half. If racers do not have a full 2 wk to acclimate, slowly and properly, showing up as close to race time as possible (e.g., morning of) is recommended. Medical team members should not allow symptomatic runners to ascend to higher altitudes (11). Runners who continue having symptoms during or after the race should descend within 12 h (11). Acclimatization occurs at different rates in each individual (11,37). Slow ascent is an accepted way to prevent AMS and HACE; however this may not be possible during an ultramarathon race but may be accomplished partially the day or two before the race. Acetazolamide, dexamethasone, ibuprofen, phosphodiesterase-5 inhibitors, β agonists, and occasionally verapamil (for HAPE) may be used as prophylaxis (SOR C).

Heat-Related Illness

Heat-related illnesses represent a variety of disorders from mild heat edema to heat stroke. Acclimatization is an important body adaptation with physiologic changes like increase in plasma volume and sweating, which usually takes about 10 to 14 d (37). Ultramarathon runners should acclimatize in the temperatures close to the race environment, which means, for most races, training in extreme heat and cold, but this may be difficult to achieve with sustained exposure for a few weeks before a race. Risk factors for heat-related illnesses include extremes in age (<15 or >65 years); comorbid medical conditions (i.e., respiratory, cardiovascular, and hematologic); medication use (e.g., alcohol, ephedra, diet pills, thyroid agonists, β-blockers, calcium channel blockers, diuretics, and illicit drugs); fitness status; poor acclimatization; long high-intensity physical activity; environmental conditions (temperature, humidity, and sun exposure); and the availability of water, rest, and shade (37). A rectal thermometer is the most accurate way to measure core body temperature.

Heat edema is a mild form of heat illness that happens mainly in nonacclimatized and older runners (37). Presence of any systemic symptoms challenges the diagnosis of heat edema. It is a dependent edema mainly in feet and hands (Fig. 1) due to increased plasma volume. Management of heat edema in ultramarathoners is usually conservative with elevation and relative rest after the race. Edema may interfere with race performance and may cause dropping out of the race. Symptoms usually resolve in 1 to 2 wk (37). Compressions sleeves, frequently used by athletes for perceived performance enhancements, may reduce symptoms during a race.

Figure 1
Figure 1:
Heat edema of the hands during a 161-km ultramarathon.

Sunburn is caused by sun’s ultraviolet radiation especially between 10 a.m. and 4 p.m. Sunburn is a significant risk factor for further heat-related illness. It is more common in people with fair skin. High altitude increases the ultraviolet intensity. Frequent use of a broad spectrum sunscreen (preferably sweat-resistant sunscreen) with SPF of at least 30, strategically running in the shade, and wearing protective clothing and a hat are recommended (37). Reapplication of sunscreen after significant sweating or rain exposure is important to prevent significant burns.

Heat syncope occurs when the athlete stops running. It may occur at the finish line when the runners suddenly stop running at the end of a race. The etiology of orthostatic hypotension is venous pooling and peripheral vasodilation (37). Conservative management with rehydration and leg elevation usually resolves the symptoms.

Heat exhaustion is the most common type of heat-related illness (37). Common symptoms and signs include profuse diaphoresis, fatigue, nausea, vomiting, weakness, malaise, headache, tachycardia, and orthostatic hypotension. Mental status is usually intact. If not treated, heat exhaustion may progress to heat stroke (37). Differential diagnosis is broad and includes high altitude illness, exercise-associated hyponatremia (EAH), and hypoxia. Cooling the runner by removing him from the heat and providing cold electrolyte-containing fluids should begin as soon as possible. Cool water immersion and intravenous (IV) fluid rehydration may be considered in runners with persistent symptoms.

Exertional heat stroke (EHS) is a true medical emergency requiring immediate intervention. EHS is characterized by core body temperature of 40°C (104°F to 105°F) or higher and severe mental status impairment (i.e., irritability, seizures, confusion, psychotic behavior, ataxia, and coma). Treatment should be started even when the diagnosis is suspected, and immediate cooling saves lives. While complying with the advanced cardiovascular life support algorithm, immediate cooling, preferable in an ice bath, should be started. The patient should be transferred to the hospital after initial stabilization.

Cold Injuries

Hypothermia occurs when the core body temperature drops to below 35°C (95°F). Hypothermia can happen at the end of an ultramarathon or when a runner stops on the course for a long time. Inexperienced runners can become exhausted faster when the weather changes unexpectedly (wind, rain, and snow) (37). Evaporation is a significant source of heat loss in high altitudes in the presence of wind chill and wet clothing (37). Ultramarathon courses with the possibility of water immersion (crossing rivers) and nocturnal running in lower temperatures increase the risk of hypothermia. Obtaining core body temperature measurement (rectal) is essential in the diagnosis of hypothermia. The first priority in management of runners with hypothermia is stopping heat loss by removing wet clothes and insulating the body with blankets and garments (passive rewarming). Management of moderate to severe hypothermia usually requires external active rewarming (hot water circulating blankets, hot packs, forced-air warming systems, and heat lamps) (37). Internal active rewarming (e.g., hemodialysis, heated IV fluids, and cardiopulmonary femoral bypass) is available only in the hospital settings for severe cases (37).

Frostnip is a superficial cold-induced vasoconstriction in the skin happening usually at freezing temperatures. Frostnip affects only the superficial layers of the skin, resulting in skin blanching and numb patches mostly in the nose, ears, chin, and cheeks. Skin that crystallizes in the cold or wind experiences frostnip and should be rewarmed immediately. Frostnip resolves rapidly with gentle rewarming without any sequelae (37), but it warns of risk of frostbite, and if conditions are ignored, significant injury may occur.

Frostbite is a freezing injury to the skin and underlying tissues with formation of crystals in extracellular space between cells (37). Frostbite occurs at below freezing temperature. Exposed areas (nose, ears, cheeks, and digits) are affected usually with more than half of the cases occurring in the toes (37). Constrictive and wet clothes increase the risk of frostbite. A numb extremity in cold temperature should signal risk of frostbite and invite rapid rewarming. The best treatment approach is rapid rewarming with warm water (39°C to 42°C). Exercise on a frostbitten or rewarmed extremity increases risk of poor outcome.

Exertional Rhabdomyolysis

Exertional rhabdomyolysis (ER) is the breakdown of skeletal muscle fibers that results in the release of muscle proteins into the circulation. Exercise-related muscle pain, swelling, stiffness, and muscle weakness are the usual symptoms of ER. Muscle damage usually becomes evident by the elevation of creatine kinase (CK). Serum CK level should be at least 5 to 10 times the upper normal limit to confirm the diagnosis of ER, but many athletes may experience high levels of CK without rhabdomyolysis (SOR C) (24). The prevalence of symptomatic ER among ultramarathon runners is unknown, although significant exertion or exercise may increase CK levels without complications. In a recent study of 39 asymptomatic runners of a 246-km continuous race, the mean CK level after completing the race was 43,763 ± 6,764 U·L−1 (40). Men tend to show higher serum CK level than women, and African Americans tend to have higher serum CK level than Caucasians postexercise (24). This could be due to the larger average total muscle mass in men and in the African Americans compared with women and Caucasians, respectively. There is a well-established association between ER and heat injury, but the mechanism is poorly understood (24). ER may result in myoglobinuria (cola-colored urine), which can cause acute kidney injury (AKI). ER is the most common cause of exercise-associated AKI in athletes. Use of NSAIDs during the race and underlying renal problems are risk factors for developing AKI among endurance runners.

Runners with dark urine (gross myoglobinuria) should be evaluated for renal function and serum CK level. The authors recommend that all ultramarathon races have at least one fast laboratory analyzer at the finish line. Most analyzers can measure basic metabolic panel and CK level if needed. Outpatient IV and oral rehydration therapy may be appropriate in cases with normal urinary output, normal renal function, and serum CK level of less than 20,000 U·L−1 (4,24). Close monitoring of urinary output, renal function, and serum CK level is critical, and close follow-up is required. Significant cases of ER should be transferred to the hospital for close monitoring and management (4,24).


EAH can occur during or up to 24 h after a prolonged exertion. It is one of the most important medical problems in endurance events. The prevalence of EAH in marathon runners is about 20% (22). In one study, 14 (30%) runners developed asymptomatic EAH in a 161-km race (18). In another study, five (5%) runners developed asymptomatic EAH in a 100-km race (22). The true prevalence of symptomatic EAH among ultramarathon runners is unknown, but time spent on the course compared with marathons and time to consume large volumes of fluid are concerning. Anecdotally the authors believe that the prevalence of symptomatic EAH in ultramarathons is less than that of marathons, perhaps due to more experience of ultramarathoners managing fluid status properly. Generally symptoms occur after the serum [Na+] levels have fallen below 120 to 125 mmol·L−1 or decreased by at least 7% of the baseline values. Most of the clinical manifestations are related to cerebral and pulmonary edema. They include headaches, nausea, and vomiting in the early phase and disorientation, confusion, coma, seizures, and signs of pulmonary edema later on (32). Weight gain, swollen digits with tight rings or jewelry, and headache, especially with confusion, should be considered to be hyponatremia until proven otherwise. The primary etiologic factor in EAH is fluid consumption in excess of fluid losses in prolonged exertion. Altered fluid requirements and increased production of arginine vasopressin peptide during endurance exercise may further complicate the conditions. The role of excessive sodium losses by sweating in the development of EAH is yet to be determined. NSAIDs also may be a contributing factor thru alterations in renal function (32). This can be of particular importance since it has been reported that 60.5% of finishers and 46.4% of nonfinishers in an ultramarathon race have used NSAIDs (16).

EAH should be treated urgently in the presence of cerebral edema. A bolus of hypertonic saline may be used in cases with neurological symptoms once sodium level is confirmed, preferably in a medical center (32). If serum [Na+] results are not available and there is a high degree of clinical suspicion, administration of all fluids should be restricted until a healthy urine output is established (32) and until sodium level is obtained. Athletes ideally can lose up to 2% of their weight after a long run, often more, and a normal weight may signify abnormal fluid and electrolyte status. In order to prevent EAH, ultramarathoners should drink only when they feel thirsty and should monitor their weight to avoid weight gain during or after exercise (32), aiming for a weight loss of around 2%. The role of salt supplementation during ultramarathon races in preventing EAH is not clear (13,32).

Respiratory Illnesses

The exact prevalence of upper and lower respiratory tract symptoms during and after ultramarathons is unknown. Exercise-induced bronchospasm is probably more common among ultramarathon runners (SOR C) (6). Predisposing factors include exposure to environmental triggers like dust, allergens, cold weather, and high altitude. Runners with lower respiratory symptoms and signs (e.g., shortness of breath and wheezing) should be evaluated for other conditions like pulmonary edema (HAPE and EAH). Each aid station should be supplied with oxygen and albuterol inhalers. Upper respiratory infection may increase the risk for HAPE. The authors recommend disqualifying any runners who require supplemental oxygen or IV fluids during the race.

Dermatologic Problems

Dermatologic problems are quite common among runners, but the exact prevalence in ultramarathon runners is unknown.

Foot Blister (Bulla)

In a survey study of two 161-km races, 40.1% of finishers and 17.3% of nonfinishers reported having blisters (16). Blisters were also the cause of drop out in 5.8% of nonfinishers (16). Blisters are the most common reported injuries in marathons with the incidence of 0.2% to 39% (26). The most common locations include the distal aspects of the toes, the balls of the feet, and the posterior heel (Fig. 2). Risk factors for the formation of blisters include heat, moisture, ill-fitting shoes, and increased running volume (26). Painful blisters can be punctured with a sharp sterile instrument, trying to keep the blister roof. Preventive measures include wearing appropriate footwear, moisture wicking synthetic socks, and dry socks. Applying drying powder or petroleum jelly also may help. Colloid type dressings, such as DuoDERM, may minimize blister pain and help athletes complete long events.

Figure 2
Figure 2:
Posterior heel blisters (bullas) following completion of a 161-km ultramarathon.

Chafing and Abrasion

Chafing is a superficial inflammatory dermatitis as a result of skin rubbing against skin or clothing. It is a painful inflamed oozing lesion. Chafing can occur anywhere on the body, but the thighs, groin, axilla, and nipples (runner’s nipples) are more common locations. Abrasion is a superficial (no deeper than epidermis) damage to the skin often caused by a fall. It is more severe than a chafing; however bleeding, if present, is minimal. Chafing and abrasions can be treated by cleaning with soap and water and drying the areas. Applying a drying powder, petroleum jelly, aquaphor, topical antibiotic, or topical steroids also may alleviate the pain. Wearing dry and well-fitting clothes are important for prevention of chafing (26). Placing tape over the nipples may reduce short-term symptoms during a race by reducing friction.

Corn and Callus

Hyperkeratoses over the bony prominences of the feet and toes occur as a protective mechanism in response to repetitive pressure or friction. Corns are small, conical lesions with a painful central core. In contrast, calluses usually cause minimum pain and lack a central core. Blisters may occur beneath these lesions during races, and appropriate footwear, pairing, hydrocolloid dressing, and moisture-wicking socks are important for prevention.

Subungual hematoma occurs in 2.5% in marathon runners (26). The etiology is repetitive, pushing of the longest toe (first or second) into the toebox, especially during downhill running. Repetitive forces and terrain demands in ultramarathons may increase risk of hematoma. Treatment is usually conservative; however painful hematomas can be drained using a sterile needle.

Exercise-Related Pain

Almost all runners develop pain as a result of participating in an ultramarathon. There are two types of exercise-related pain: 1) general muscle soreness and fatigue and 2) pain due to specific injuries. Participating in an endurance aerobic activity induces an acute (up to 30 min) analgesic effect (17). The exact mechanism of exercise-induced analgesia is unknown. It seems that the fastest ultramarathon runners experience a modest temporary reduction in pressure pain perception following the race (17).

NSAIDs should be used cautiously during intense physical activity like an ultramarathon due to an increased risk of severe complications like renal failure and GI bleeding. This risk is increased with dehydration and other comorbidities such as ER and heat illness. However many runners still use significant amount of NSAIDs during and after the ultramarathons (16). In one 161-km ultramarathon in 2011, 25.7% and 42.2% of runners reported taking NSAIDs during and after the race, respectively (41). The rate of self-reported NSAIDs use during the race was a disturbing 39.7% at the same race in 2008 (1). Postrace NSAID use should be delayed until adequate urine output is established.


Medical coverage of ultramarathon is a challenging task that requires hours of preparation and planning. Course medical directors and volunteer clinicians should be familiar with the common injuries and illnesses unique to their race. We recommend careful documentation of all injuries and illnesses using an injury surveillance system. The ultimate goal is to have a national and an international mortality and morbidity registry. This will improve the safety and health of all ultramarathoner runners.

The authors would like to thank Mr. John Nagle for editing the manuscript.

The authors declare no conflict of interest and do not have any financial disclosures.


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