Clinical Impact of Speed Variability to Identify Ultramarathon Runners at Risk for Acute Kidney Injury

Exertional Rhabdomyolysis in Athletes: Systematic Review and Current Perspectives

OBJECTIVE

Exertional rhabdomyolysis results from a breakdown of skeletal muscle cells after intense exercise in otherwise healthy patients, causing increased levels of creatine kinase (CK) or myoglobin, as well as urine dipstick positive for blood, and may result in kidney insufficiency. The aim of this study was to outline the current perspectives of exertional rhabdomyolysis in athletes and subsequent treatment based on the current literature.

DATA SOURCES

We searched the MEDLINE/PubMed and Google databases for ([exercise] OR [exertional]) AND rhabdomyolysis following the PRISMA guidelines. All abstracts were reviewed by 2 independent examiners. Inclusion criteria consisted of original articles presenting studies on exertional rhabdomyolysis or exercise-induced rhabdomyolysis with 7 or more cases. All case reports, case series, or editorials were excluded.

MAIN RESULTS

A total of 1541-abstracts were screened, leaving 25 studies for final inclusion and analysing 772patients. Especially, young male patients were affected at a mean age of 28.7 years (range 15.8-46.6 years). Most of the athletes performed running, including marathons in 54.3% of cases (n = 419/772), followed by weightlifting in 14.8% (n = 114/772). At the time of presentation, the mean creatine kinase was 31 481 IU/L (range 164-106,488 IU/L). Seventeen studies reported the highest level of CK, which was 38 552 IU/L (range 450-88,496 IU/L). For treatment, hydration was the most common method of choice reported by 8 studies.

CONCLUSIONS

Exertional rhabdomyolysis seems to be underestimated, and it is essential to screen patients who present with muscle soreness/cramps and/or dark urine after heavy endurance events to avoid any further complications.

LEVEL OF EVIDENCE

II; systematic review.

Ultra-Endurance Participation and Acute Kidney Injury: A Narrative Review

Increasingly popular, ultra-endurance participation exposes athletes to extremely high levels of functional and structural damage. Ultra-endurance athletes commonly develop acute kidney injury (AKI) and other pathologies harmful to kidney health. There is strong evidence that non-steroidal anti-inflammatory drugs, common amongst ultra-athletes, is linked to increased risk and severity of AKI and potentially ischaemic renal injury, i.e., acute tubular necrosis. Ultra-endurance participation also increases the risk of exertional rhabdomyolysis, exercise-associated hyponatremia, and gastrointestinal symptoms, interlinked pathologies all with potential to increase the risk of AKI. Hydration and fuelling both also play a role with the development of multiple pathologies and ultimately AKI, highlighting the need for individualised nutritional and hydration plans to promote athlete health. Faster athletes, supplementing nitrates, and being female also increase the risk of developing AKI in this setting. Serum creatinine criteria do not provide the best indicator for AKI for ultra-athletes therefore further investigations are needed to assess the practicality and accuracy of new renal biomarkers such as neutrophil gelatinase-associated lipocalin (NGAL). The potential of recurring episodes of AKI provide need for further research to assess the longitudinal renal health impact of ultra-participation to provide appropriate advice to athletes, coaches, medical staff, and event organisers.

Could Repeated Cardio-Renal Injury Trigger Late Cardiovascular Sequelae in Extreme Endurance Athletes?

Regular exercise confers multifaceted and well-established health benefits. Yet, transient and asymptomatic increases in markers of cardio-renal injury are commonly observed in ultra-endurance athletes during and after competition. This has raised concerns that chronic recurring insults could cause long-term cardiac and/or renal damage. Indeed, extreme endurance exercise (EEE) over decades has sometimes been linked with untoward cardiac effects, but a causal relation with acute injury markers has not yet been established. Here, we summarize the current knowledge on markers of cardiac and/or renal injury in EEE athletes, outline the possible interplay between cardiac and kidney damage, and explore the roles of various factors in the development of potential exercise-related cardiac damage, including underlying diseases, medication, sex, training, competition, regeneration, mitochondrial dysfunction, oxidative stress, and inflammation. In conclusion, despite the undisputed health benefits of regular exercise, we speculate, based on the intimate link between heart and kidney diseases, that in rare cases excessive endurance sport may induce adverse cardio-renal interactions that under specific, hitherto undefined conditions could result in persistent cardiac damage. We highlight future research priorities and provide decision support for athletes and clinical consultants who are seeking safe strategies for participation in EEE training and competition.

Acute Kidney Injury and Hyponatremia in Ultra-Trail Racing: A Systematic Review

Background and objectives: Ultra-trail races can cause episodes of acute kidney injury (AKI) and exercise-associated hyponatremia (EAH) in healthy subjects without previous renal pathology. This systematic review aims to review the incidence of these two syndromes together and separately taking into account the length and elevation of the ultra-trail race examined. Materials and Methods: A systematic review was conducted through electronic search in four electronic databases (PubMed, EBSCO, Web of Science and Alcorze). Results: A total of 1127 articles published between January 2006 and December 31, 2021 were included, 28 of which met the inclusion criteria. The studies were categorized according to the length and stages of the race in four categories: medium (42 to 69 km), long (70 to 99 km), extra (>100 km) and multi-stage if they included various stages. A total of 2950 runners (666 females and 2284 males) were extracted from 28 publications. The AKI incidence found was 42.04% (468 cases of 1113), and 195 of 2065 were diagnosed with EAH, accounting for 9.11%. The concurrence of both pathologies together reached 11.84% (27 individuals) from a total of 228 runners with AKI and EAH simultaneously analyzed. Sorted by race category, the AKI+EAH cases were distributed as follows: 18 of 27 in the extra (13.63% and n = 132), 4 in the large (5.79% and n = 69) and 5 in the medium category (18.15% and n = 27). Conclusions: According to these results, extra and medium races showed a similar incidence of AKI+EAH. These findings underline the importance of the duration and intensity of the race and may make them responsible for the etiology of these medical conditions. Due to their variable incidence, EAH and AKI are often underdiagnosed, leading to poorer prognosis, increased condition seriousness and hindered treatment. The results of this review urge participants, coaches and race organizers to take measures to improve the early diagnosis and urgent treatment of possible EAH and AKI cases.

Serum and Urinary Neutrophil Gelatinase-Associated Lipocalin Are Not Associated With Serum Redox Parameters in Amateur Athletes After an Ultramarathon

Objective

To evaluate the relationship between oxidative stress and NGAL levels in blood and urine of amateur athletes after participating in a 100 km ultramarathon.

Methodology

The sample was composed of seven athletes, submitted to anthropometric assessment, cardiopulmonary exercise test, collection of urine and blood, measurement of body weight. The rate of perceived exertion (RPE), competition duration, heart rate (HR), energy expenditure and oxygen consumption (V'O2") were also measured during the event. The energy consumption during the race was verified at its end. The analyses were based on the means (M) and respective standard deviations (SD), with statistical significance set at 5% (p < 0.05). Paired t-test was used for comparison between the periods before and after the competition, and Pearson's correlation coefficient was used to measure the linear correlation between quantitative variables.

Results

Body mass index (BMI) of the sample was 25.75 kg/m2 ± 3.20, body fat percentage 18.54% ± 4.35% and V'O2"max 48.87% ± 4.78. Glucose, cortisol, and neutrophil gelatinase-associated lipocalin (NGAL) (p < 0.01) as well as glutathione peroxidase (GPx) active were higher after the race when compared to basal values. Moreover, lactate, creatinine, microalbuminuria, and glomerular filtration rate (GFR) (p < 0.001) were also higher after the race. After the competition, there was a significant correlation only between serum NGAL and creatinine, which was classified as strong and positive (r: 0.77; p < 0.05). There was a significant reduction (p < 0.05) of body weight after the event (72.40 kg ± 9.78) compared to before it (73.98 kg ± 10.25). In addition, we found an increase of RPE (p < 0.001) after the race. The competition lasted 820.60 min (±117.00), with a 127.85 bpm (±12.02) HR, a 2209.72 kcal ± 951.97 energy consumption, 7837.16 kcal ± 195.71 energy expenditure, and 28.78 ml/kg/min-1 (±4.66) relative V'O2"max.

Conclusion

The lack of correlation between oxidative stress biomarkers and serum and urine NGAL suggests that NGAL is more sensitive to inflammatory processes than to ROS levels.

Renal Function Recovery Strategies Following Marathon in Amateur Runners

Long distance races have a physiological impact on runners. Up to now, studies analyzing these physiological repercussions have been mainly focused on muscle and cardiac damage, as well as on its recovery. Therefore, a limited number of studies have been done to explore acute kidney failure and recovery after performing extreme exercises. Here, we monitored renal function in 76 marathon finishers (14 females) from the day before participating in a marathon until 192 h after crossing the finish line (FL). Renal function was evaluated by measuring serum creatinine (sCr) and the glomerular filtration rate (GFR). We randomly grouped our cohort into three intervention groups to compare three different strategies for marathon recovery: total rest (REST), continuous running at their ventilatory threshold 1 (VT1) intensity (RUN), and elliptical workout at their VT1 intensity (ELLIPTICAL). Interventions in the RUN and ELLIPTICAL groups were performed at 48, 96, and 144 h after marathon running. Seven blood samples (at the day before the marathon, at the FL, and at 24, 48, 96, 144, and 192 h post-marathon) and three urine samples (at the day before the marathon, at the finish line, and at 48 h post-marathon) were collected per participant. Both heart rate monitors and triaxial accelerometers were used to control the intensity effort during both the marathon race and the recovery period. Contrary to our expectations, the use of elliptical machines for marathon recovery delays renal function recovery. Specifically, the ELLIPTICAL group showed a significantly lower ∆GFR compared to both the RUN group (p = 4.5 × 10−4) and the REST group (p = 0.003). Hence, we encourage runners to carry out an active recovery based on light-intensity continuous running from 48 h after finishing the marathon. In addition, full resting seems to be a better strategy than performing elliptical workouts.

Acute Kidney Injury Biomarkers and Hydration Outcomes at the Boston Marathon

The purpose of our field study was to investigate the effects of running the Boston Marathon on acute kidney injury (AKI) biomarkers. We hypothesized that biomarker values would be elevated immediately post-marathon but would resolve in the 24-h post-marathon. Secondarily, we sought to identify sex differences related to renal stress. Participants were 65 runners who completed the Boston Marathon (46 ± 9 years, 65.4 ± 10.8 kg). Urine samples were collected at three different time points (pre-marathon, post-marathon, and 24-h post-marathon). Blood samples were collected post-marathon and 24-h post-marathon. Urine specific gravity (USG) and AKI biomarkers were evaluated. Pre-marathon USG (1.012 ± 0.007) was significantly less than post-marathon (1.018 ± 0.008) and 24-h post-marathon (1.020 ± 0.009; P < 0.001). Male USG (1.024 ± 0.009) was significantly greater 24-h post-marathon than females (1.017 ± 0.008; P = 0.019). Urinary neutrophil gelatinase-associated lipocalin values were significantly greater over time (P < 0.001), and there was a main effect of sex with female urinary creatinine (_UCr) greater than males at all three time points (P = 0.040). Post-marathon_UCr (366.24 ± 295.16 mg/dl) was significantly greater than pre-marathon (206.65 ± 145.28.56 mg/dl; p < 0.001) and 24-h post-marathon was significantly lower than other time-points (93.90 ± 125.07 mg/dl; P < 0.001). Female_UCr values were significantly greater than males 24-h post-marathon (P < 0.001). There was no difference in serum cystatin C (_SCys) values post- or 24-h post-marathon (P = 0.178). Serum creatinine (_SCr) significantly decreased between post-marathon and 24-h post-marathon, (P < 0.001). We can infer that the characteristics unique to the Boston Marathon may have attributed to prolonged elevations in AKI biomarkers. Sex differences were observed during the Boston Marathon warranting further investigation.

Kidney physiology and pathophysiology during heat stress and the modification by exercise, dehydration, heat acclimation and aging

The kidneys' integrative responses to heat stress aid thermoregulation, cardiovascular control, and water and electrolyte regulation. Recent evidence suggests the kidneys are at increased risk of pathological events during heat stress, namely acute kidney injury (AKI), and that this risk is compounded by dehydration and exercise. This heat stress related AKI is believed to contribute to the epidemic of chronic kidney disease (CKD) occurring in occupational settings. It is estimated that AKI and CKD affect upwards of 45 million individuals in the global workforce. Water and electrolyte disturbances and AKI, both of which are representative of kidney-related pathology, are the two leading causes of hospitalizations during heat waves in older adults. Structural and physiological alterations in aging kidneys likely contribute to this increased risk. With this background, this comprehensive narrative review will provide the first aggregation of research into the integrative physiological response of the kidneys to heat stress. While the focus of this review is on the human kidneys, we will utilize both human and animal data to describe these responses to passive and exercise heat stress, and how they are altered with heat acclimation. Additionally, we will discuss recent studies that indicate an increased risk of AKI due to exercise in the heat. Lastly, we will introduce the emerging public health crisis of older adults during extreme heat events and how the aging kidneys may be more susceptible to injury during heat stress.

Exertional rhabdomyolysis and acute kidney injury in endurance sports: A systematic review

The increase of wide-spread participation in endurance events in sports such as open water swimming, cycling, running and triathlons, has given rise to a concern about potential implications for renal function and kidney health. This study aimed to delve into the findings on exertional rhabdomyolysis (ER) and acute kidney injury (AKI) in endurance sports, emphasizing the diagnostic criteria used, physical and environmental contextual conditions in which ER and AKI are reported. Following PRISMA guidelines for systematic reviews and meta-analysis, topic related studies were searched digital sources (from 2009 to 2020). Studies with biomarkers of ER and AKI reported in endurance or ultra-endurance events were included. A total of 43 publications (sample = 813) were extracted, and 345 (43.5%) individuals were diagnosed with ER (creatinine kinase > 5000 UI/L) and 130 (16.39%) with ER + AKI (creatinine ≥ 1.88 mg/dL). Out of the total cases of ER + AKI, 96.92% were in ultra-endurance runners. There were inconsistences between studies in diagnosis criteria for ER and AKI, which represented a difficulty in the interpretation of the data. Increased levels of muscle and kidney injury immediately after endurance events were reported, but after 5.86 days these levels usually returned to baseline. There is a lack of knowledge around the potential of repeated ER and AKI predisposing to long-term chronic kidney disease. More accurate markers for subclinical and functional AKI diagnosis are needed in the analysis of kidney health after endurance events. ER and AKI are serious clinical problems with significant morbidity. Further research may be in order to help define future prevention strategies.

Short-term ubiquinol-10 supplementation alleviates tissue damage in muscle and fatigue caused by strenuous exercise in male distance runners

Background: Coenzyme Q10 (CoQ10) is the electron transporter in oxidative phosphorylation and an endogenous antioxidant. Recent researches have indicated that doses of 200-300 mg/day are needed to recognize effects to prevent oxidative damage in athletes, and the reduced form of CoQ10, ubiquinol-10, is more bioavailable than its oxidized form. Therefore, we hypothesized that higher doses of ubiquinol-10 could elevate plasma CoQ10 levels rapidly and exert physiological benefits in athletes. Therefore, a placebo controlled, double blinded test was carried out to determine the effects of ubiquinol-10 on the extravasate enzymes and fatigue levels of distance runners. Methods: Sixteen male collegiate distance runners were allocated to two groups receiving 300 mg/day of ubiquinol-10 (19.8 ± 1.7 years) or a placebo (20.1 ± 1.6 years) for 12 days during summer training that comprised 25- and 40-km runs on days 7 and 9, respectively. Results: Ubiquinol-10 elevated plasma CoQ10 concentration to 5.62 μg/mL and significantly decreased activities of the serum extravasate enzymes, CK, ALT, LDH (P < 0.01), and AST (P < 0.05) on day 6. Subjective fatigue status was significantly elevated on day 10 (the day after the 45-km run) in the placebo group (P < 0.001), but did not significantly change in the group given ubiquinol-10. Therefore, ubiquinol-10 could mitigate tissue damage and alleviate fatigue status in distance runners during summer training. Conclusions: Ubiquinol-10 (300 mg/day) supplementation elevated plasma CoQ10 concentrations almost to plateau levels, decreased extravasate enzymes within six days, and suppressed the subjective fatigue in male distance runners.

Impact of renin-angiotensin-aldosterone system activation and body weight change on N-terminal pro-B-type natriuretic peptide variation in 100-km ultramarathon runners

BACKGROUND

The change in N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels follows a paradox imposed by strenuous endurance exercise. Previous reports showed significant body weight (BW) loss was common in ultramarathon runners. This study investigated whether the BW change and renin-angiotensin-aldosterone system activation contribute to exercise-induced NT-proBNP release.

METHODS

A total of 26 participants who finished a 100 km ultramarathon in Taiwan were enrolled. For each participant, blood samples and spot urine samples were collected 1 week before the race, as well as immediately and 24 hours after the finish. BW change was recorded to monitor the hydration status.

RESULTS

Prolonged endurance exercise led to a substantial increase in NT-proBNP. Compared with prerace values, NT-proBNP levels significantly increased immediately after the race (24.3 ± 20.2 pg/mL to 402.9 ± 305.9 pg/mL, p < 0.05) and maintained high levels until 24 hours after the race (143.7 ± 126.1 pg/mL, p < 0.05). The fractional excretion of sodium values was below 1% in three different time points. The 100 km ultramarathon resulted in significant BW loss and elevated renin and aldosterone levels. However, only 24 hours after the race, a positive significant relationship was found between NT-proBNP and aldosterone levels (p = 0.007, r = 0.267), but a negative significant relationship between NT-proBNP and BW increased during the recovery phase (p < 0.001, r = 0.372).

CONCLUSION

The mechanism of NT-proBNP release immediately following the race was multifaceted. During the recovery phase, rehydration might lead to the decrease of NT-proBNP. Our observations with regard to aldosterone and NT-proBNP might be in response to help the body maintains hydration state.

Physiological and Pathophysiological Responses to Ultramarathon Running in Non-elite Runners

Ultramarathon running represents a major physical challenge even for elite athletes. Runners wellbeing may be challenged by fluid and electrolyte disturbances, hemolysis and skeletal muscle damage, decline in hepatic function and kidney injury. We hypothesized that these effects may even be exacerbated in non-elite runners. Physiological, hematological and biochemical parameters of ten males (26–45 years, weekly training time 8.5 h), participating in a mountain ultramarathon (67 km; approximately 4,500 m of total ascent), were determined before (PRE), immediately after finishing the ultramarathon (POST), and 24 h after the individual finish (REC). Race times of the 8 finishers (2 drop-outs due to hot ambient temperature) varied between 10.4 and 16.1 h, which almost represents the range of the entire starter field (8.82 h–17.47 h). The following changes in mean values of selected markers for skeletal muscle damage and kidney injury were observed from PRE to POST: creatine kinase (CK) + 1289%, lactate dehydrogenase (LDH) + 87%, serum creatinine (CR) + 72%, blood urea nitrogen (BUN) + 96%, and estimated glomerular filtration rate (eGFR) – 45%. Values of CK + 1447%, LDH + 56%, and BUN + 71% remained elevated at REC. White blood cells were increased (+ 137%) only POST. In conclusion, CK and LDH levels and leucocytosis may be considered to be relatively harmless “side-effects” of prolonged running in this group of male subjects with rather moderate ultramarathon experience and training status. However, acute kidney injury may become clinically relevant in this population under the certain conditions, which should be considered by responsible race managers and medical advisors.

External Workload Indicators of Muscle and Kidney Mechanical Injury in Endurance Trail Running

Muscle and kidney injury in endurance athletes is worrying for health, and its relationship with physical external workload (eWL) needs to be explored. This study aimed to analyze which eWL indexes have more influence on muscle and kidney injury biomarkers. 20 well-trained trail runners (age = 38.95 ± 9.99 years) ran ~35.27 km (thermal-index = 23.2 ± 1.8 °C, cumulative-ascend = 1815 m) wearing inertial measurement units (IMU) in six different spots (malleolus peroneus [MPleft/MPright], vastus lateralis [VLleft/VLright], lumbar [L1-L3], thoracic [T2-T4]) for eWL measuring using a special suit. Muscle and kidney injury serum biomarkers (creatin-kinase [sCK], creatinine (sCr), ureic-nitrogen (sBUN), albumin [sALB]) were assessed pre-, -post0h and post24h. A principal component (PC) analysis was performed in each IMU spot to extract the main variables that could explain eWL variance. After extraction, PC factors were inputted in multiple regression analysis to explain biomarkers delta change percentage (Δ%). sCK, sCr, sBUN, sALB presented large differences (p < 0.05) between measurements (pre < post24h < post0h). PC's explained 77.5-86.5% of total eWL variance. sCK Δ% was predicted in 40 to 47% by L1-L3 and MPleft; sCr Δ% in 27% to 45% by L1-L3 and MPleft; and sBUN Δ% in 38%-40% by MPright and MPleft. These findings could lead to a better comprehension of how eWL (impacts, player load and approximated entropy) could predict acute kidney and muscle injury. These findings support the new hypothesis of mechanical kidney injury during trail running based on L1-L3 external workload data.

The Potential for Renal Injury Elicited by Physical Work in the Heat

An epidemic of chronic kidney disease (CKD) is occurring in laborers who undertake physical work in hot conditions. Rodent data indicate that heat exposure causes kidney injury, and when this injury is regularly repeated it can elicit CKD. Studies in humans demonstrate that a single bout of exercise in the heat increases biomarkers of acute kidney injury (AKI). Elevations in AKI biomarkers in this context likely reflect an increased susceptibility of the kidneys to AKI. Data largely derived from animal models indicate that the mechanism(s) by which exercise in the heat may increase the risk of AKI is multifactorial. For instance, heat-related reductions in renal blood flow may provoke heterogenous intrarenal blood flow. This can promote localized ischemia, hypoxemia and ATP depletion in renal tubular cells, which could be exacerbated by increased sodium reabsorption. Heightened fructokinase pathway activity likely exacerbates ATP depletion occurring secondary to intrarenal fructose production and hyperuricemia. Collectively, these responses can promote inflammation and oxidative stress, thereby increasing the risk of AKI. Equivalent mechanistic evidence in humans is lacking. Such an understanding could inform the development of countermeasures to safeguard the renal health of laborers who regularly engage in physical work in hot environments.

Physiology and Pathophysiology in Ultra-Marathon Running

In this overview, we summarize the findings of the literature with regards to physiology and pathophysiology of ultra-marathon running. The number of ultra-marathon races and the number of official finishers considerably increased in the last decades especially due to the increased number of female and age-group runners. A typical ultra-marathoner is male, married, well-educated, and ~45 years old. Female ultra-marathoners account for ~20% of the total number of finishers. Ultra-marathoners are older and have a larger weekly training volume, but run more slowly during training compared to marathoners. Previous experience (e.g., number of finishes in ultra-marathon races and personal best marathon time) is the most important predictor variable for a successful ultra-marathon performance followed by specific anthropometric (e.g., low body mass index, BMI, and low body fat) and training (e.g., high volume and running speed during training) characteristics. Women are slower than men, but the sex difference in performance decreased in recent years to ~10–20% depending upon the length of the ultra-marathon. The fastest ultra-marathon race times are generally achieved at the age of 35–45 years or older for both women and men, and the age of peak performance increases with increasing race distance or duration. An ultra-marathon leads to an energy deficit resulting in a reduction of both body fat and skeletal muscle mass. An ultra-marathon in combination with other risk factors, such as extreme weather conditions (either heat or cold) or the country where the race is held, can lead to exercise-associated hyponatremia. An ultra-marathon can also lead to changes in biomarkers indicating a pathological process in specific organs or organ systems such as skeletal muscles, heart, liver, kidney, immune and endocrine system. These changes are usually temporary, depending on intensity and duration of the performance, and usually normalize after the race. In longer ultra-marathons, ~50–60% of the participants experience musculoskeletal problems. The most common injuries in ultra-marathoners involve the lower limb, such as the ankle and the knee. An ultra-marathon can lead to an increase in creatine-kinase to values of 100,000–200,000 U/l depending upon the fitness level of the athlete and the length of the race. Furthermore, an ultra-marathon can lead to changes in the heart as shown by changes in cardiac biomarkers, electro- and echocardiography. Ultra-marathoners often suffer from digestive problems and gastrointestinal bleeding after an ultra-marathon is not uncommon. Liver enzymes can also considerably increase during an ultra-marathon. An ultra-marathon often leads to a temporary reduction in renal function. Ultra-marathoners often suffer from upper respiratory infections after an ultra-marathon. Considering the increased number of participants in ultra-marathons, the findings of the present review would have practical applications for a large number of sports scientists and sports medicine practitioners working in this field.

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Zusammenfassung. Wir stellen die wichtigsten Erkenntnisse zu Organschädigungen durch einen Ultramarathon zusammen. Nach einem Ultramarathon können kardiale Biomarker wie CK, CK-MB, kardiales Troponin I (cTnI) und N-terminales pro-Brain Natriuretic Peptide (NT-pro BNP) erhöht sein. Bis 80 % und mehr der Finisher klagen über Verdauungsprobleme, die einer der Hauptgründe sind, einen Ultramarathon nicht zu finishen. Bis zu 90 % der Läufer, die einen Ultramarathon aufgeben, klagen über Übelkeit. Nach einem Ultramarathon steigen die Leberwerte oft an, schwerwiegende Konsequenzen bleiben meist aus. Risikofaktoren für eine Einschränkung der Nierenfunktion sind eine ausgeprägte Muskelschädigung mit Rhabdomyolyse, Dehydratation, Hypotonie, Hyperurikämie, Hyponatriämie, geringe Wettkampferfahrung sowie die Einnahme von NSARs. Ultraläufer leiden nach einem Ultramarathon oft an Infekten der oberen Atemwege.

Acute kidney injury associated with endurance events-is it a cause for concern? A systematic review

INTRODUCTION

A growing body of evidence suggests even small rises in serum creatinine (SCr) are of considerable clinical relevance. Given that participants in endurance events are exposed to potential (repeated) renal insults, a systematic review was undertaken to collate current evidence for acute kidney injury (AKI), complicating such events.

METHODS

A systematic review of studies and case reports meeting inclusion criteria on Medline and EMBASE (inception to October 2015). Included: studies with markers of renal function before and after endurance or ultraendurance events; case reports of severe AKI. Two reviewers assessed risk of bias using the Newcastle-Ottawa scale.

RESULTS

Eleven case report publications (n=27 individuals) of severe AKI, were retrieved, with risk factors including systemic illness or nephrotoxic medications usually identified. From 30 studies of endurance and ultraendurance events, mean rise in SCr was 29 (±12.3) µmol/L after marathon or ultramarathon (17 studies, n=568 participants) events. Where follow-up tests were conducted, SCr returned to baseline within 48 hours. Rises in biomarkers suggest potential parenchymal insult, rather than simply muscle breakdown. However, evidence of long-term deleterious effects is lacking.

CONCLUSIONS

Raised levels of SCr are reported immediately after endurance events. It is not clear whether this is either clinically significant, or if repeated participation predisposes to long-term sequelae. The aetiology of severe exercise-associated AKI is usually multifactorial, with risk factors generally identified in the rare cases reported. On-site biochemistry, urine analysis and biomarkers of AKI may help identify collapsed runners who are at significant short-term risk and allow suitable follow-up.

Correction: Clinical Impact of Speed Variability to Identify Ultramarathon Runners at Risk for Acute Kidney Injury

[This corrects the article DOI: 10.1371/journal.pone.0133146.].