Energy metabolism, liver and kidney function in adolescent marathon runners

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.

Xanthine Oxidoreductase Activity in Marathon Runners: Potential Implications for Marathon-Induced Acute Kidney Injury

Excess activation of circulating xanthine oxidoreductase (XOR) may contribute to the pathogenesis of widespread remote organ injury, including kidney injury. The purpose of this study was to determine the acute impact of marathon running on plasma XOR activity and to examine whether plasma XOR activity is associated with marathon-induced elevations in biomarkers of acute kidney injury (AKI). Twenty-three young men (aged 20-25 years) who participated in the 38th Tsukuba Marathon were included. Blood and urine samples were collected before, immediately, 2 h (only blood sample), and 24 h after a full marathon run. Plasma XOR activity was evaluated using a highly sensitive assay utilizing a combination of [13C2,15N2] xanthine and liquid chromatography-triple quadrupole mass spectrometry. The levels of several AKI biomarkers, such as serum creatinine and urinary liver-type fatty acid-binding protein (L-FABP) were measured in each participant. Marathon running caused a transient elevation in plasma XOR activity and levels of purine degradation products (hypoxanthine, xanthine, and uric acid) as well as serum creatinine, urinary albumin, and urinary L-FABP levels. Immediately after the marathon, individual relative changes in plasma XOR activity were independently correlated with corresponding changes in serum creatinine and urinary L-FABP levels. In addition, the magnitude of marathon-induced elevation in plasma XOR activity and levels of purine degradation products were higher in individuals who developed AKI. These findings collectively suggest that marathon running substantially influences the purine metabolism pathway including XOR activity. Moreover, activated circulating XOR can be partly associated with elevated biomarkers of AKI after marathon running.

Should Adolescents Run Marathons?: Youth Marathon Training Injury Epidemiology and Risk Factors

OBJECTIVE

Youth participation in distance running has increased, yet little data exist about the injury patterns and safety of such activity. This study seeks to determine the types and rates of injuries seen in an adolescent marathon training program.

DESIGN

Observational prospective cohort study.

SETTING

Community-based adolescent marathon training program.

PARTICIPANTS

The study enrolled 1927 students from 50 high schools (HS) and 34 middle schools (MS) participating in the 2017 to 2018 Students Run Los Angeles marathon training program.

ASSESSMENT OF RISK FACTORS

Weekly injury reports completed by running coaches. Data elements included participant demographics, weekly training distance, injury type, injury acuity, and missed training time.

MAIN OUTCOME MEASURES

Epidemiology of self-reported injury in adolescent runners.

RESULTS

A total of 583 injuries occurred in 18% of runners during the training program. High schools runners were more likely to be injured than MS runners (20.8% vs 14.2%, P < 0.001). Seventy-two percent of injuries were acute with a mean missed training time of 4.8 days (SD 4.8). The most frequent site of injury was the knee (33%). Overall, runners with injuries ran a significantly greater distance per week than uninjured runners (14.6 mi vs 12.0 mi, P < 0.001). Ninety-nine percent of marathon participants completed the race.

CONCLUSIONS

During a 28-week marathon training program, 18% of adolescent participants reported an injury. More injuries occurred in HS students, were acute, and involved the knee. This study represents one of the largest descriptions of injury prevalence in adolescent distance running and highlights a lower injury rate than adults during marathon training.

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.

Physical Exercise Exacerbates Acute Kidney Injury Induced by LPS via Toll-Like Receptor 4

Introduction: Lipopolysaccharide (LPS) is a systemic response-triggering endotoxin, which has the kidney as one of its first targets, thus causing acute injuries to this organ. Physical exercise is capable of promoting physiological alterations and modulating inflammatory responses in the infectious process through multiple parameters, including the toll-like receptor (TLR)-4 pathway, which is the main LPS signaling in sepsis. Additionally, previous studies have shown that physical exercise can be both a protector factor and an aggravating factor for some kidney diseases. This study aims at analyzing whether physical exercise before the induction of LPS endotoxemia can protect kidneys from acute kidney injury.

Methods: C57BL/6J male mice, 12 weeks old, were distributed into four groups: (1) sedentary (control, N = 7); (2) sedentary + LPS (N = 7); (3) trained (N = 7); and (4) trained + LPS (N = 7). In the training groups, the animals exercised 5×/week in a treadmill, 60 min/day, for 4 weeks (60% of max. velocity). Sepsis was induced in the training group by the application of a single dose of LPS (5 mg/kg i.p.). Sedentary animals received LPS on the same day, and the non-LPS groups received a saline solution instead. All animals were euthanized 24 h after the administration of LPS or saline.

Results: The groups receiving LPS presented a significant increase in serum urea (p < 0.0001) and creatinine (p < 0.001) concentration and renal gene expression of inflammatory markers, such as tumor necrosis factor alpha and interleukin-6, as well as TLRs. In addition, LPS promoted a decrease in reduced glutathione. Compared to the sedentary + LPS group, trained + LPS showed overexpression of a gene related to kidney injury (NGAL, p < 0.01) and the protein levels of LPS receptor TLR-4 (p < 0.01). Trained + LPS animals showed an expansion of the tubulointerstitial space in the kidney (p < 0.05) and a decrease in the gene expression of hepatic AOAH (p < 0.01), an enzyme involved in LPS clearance.

Conclusion: In contrast to our hypothesis, training was unable to mitigate the renal inflammatory response caused by LPS. On the contrary, it seems to enhance injury by accentuating endotoxin-induced TLR-4 signaling. This effect could be partly due to the modulation of a hepatic enzyme that detoxifies LPS.

Ten Marathons in Ten Days: Effects on Biochemical Parameters and Redox Balance – Case Report

Production of free radicals and oxidative damage during physical activity is a topic that is intensively studied and paid a lot of attention, first of all in professional sports. Marathon is categorized as extremely demanding sports discipline, as it induces high energy consumption and also requires special mental self-control. We presented cases of two athletes of different age, who have been on dissimilar level of sports readiness, and also had various approach to physical activity and exercise. During 10 days they ran out 10 marathons, partly on a flat terrain, and partly on hilly, which produced different level of effort in conquering the terrain. Also, both athletes had complex supplementation scheme in order to prevent electrolyte imbalance and excessive production of free radicals. Blood samples were taken in the morning and immediately after the end of the marathon. Measured oxidative stress biomarkers changed without a noticeable pattern, but these changes did not vary greatly among themselves. Catalase activity in both marathon runners was higher after marathon almost after every race for 10 days. On the other hand, amount of reduced glutathione was lower after marathon in both athletes in the same manner. Based on the obtained results we can conclude that adequate supplementation could have crucial role in prevention of oxidative damage.

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.

Quick Recovery of Renal Alterations and Inflammatory Activation after a Marathon

Purpose

We evaluated the incidence of acute kidney injury in a cohort of marathon participants.

Methods

We conducted a prospective observational study focused on evaluating the incidence of kidney damage after a marathon, and its evolution in the first 48 h after the marathon in 88 runners who completed the Valencia Marathon.

Results

From the 88 participants, 42 (48.28%) presented with acute kidney injury, mainly grade 1 (95.20%). Microscopic haematuria was observed in 29 runners (33%). Levels of interleukin 6, leukocytes, and neutrophils were markedly increased at the marathon's finish line.

Conclusions

Our results confirmed that there are slight transient changes in glomerular filtration rate and inflammatory activation after a marathon.

Haematological and serum biochemical values in Norwegian sled dogs before and after competing in a 600 km race

Background

Long-distance racing is known to cause alterations in haematological and serum biochemical parameters in sled dogs. Given that finishing status reflects the physical condition in dogs completing a race, such variations will mainly be the result of physiological adaption achieved during endurance exercise. However, changes observed in withdrawn dogs may indicate pathological conditions. The aim of this study was to reveal changes in haematological and serum biochemical values in sled dogs participating in a long-distance race, with emphasis on the withdrawn dogs. Sixty-five sled dogs participated in a clinical prospective cohort study: 46 dogs competed in the 600 km race (25 finishing and 21 withdrawn dogs), and 19 dogs served as controls. Blood sampling was performed early in the training season and after the race.

Results

When compared to control dogs, both withdrawn and finishing dogs showed significant increases in neutrophil count, C-reactive protein, blood urea nitrogen and sodium/potassium ratio. Significant decreases were found in erythrocytes and eosinophil cell count, and in haematocrit, haemoglobin, total protein, albumin, globulin, creatinine, potassium and calcium levels. Finishing dogs presented significant increases in white blood cells, large unstained cells, monocyte count and cortisol level compared to control dogs. In contrast, withdrawn dogs had significant elevations in alanine aminotransferase and alkaline phosphatase activity, as well as parameters associated with muscle metabolism, such as aspartate aminotransferase, creatine kinase and phosphorus concentration.

Conclusions

Competing sled dogs experienced minor changes in blood parameters in general, mainly revealing the same pattern among withdrawals and finishers. This might indicate that numerous changes simply reflect physiological adaption due to endurance exercise. However, the serum concentration of muscle enzymes was significantly increased only in the withdrawals, and were well above reference ranges. This reflects muscle degradation, which could be the main cause of performance failure in some of the withdrawals.

Electronic supplementary material

The online version of this article (10.1186/s13028-019-0453-5) contains supplementary material, which is available to authorized users.

Response of Gut Microbiota to Metabolite Changes Induced by Endurance Exercise

A few animal studies have shown that wheel running could reverse an unhealthy status by shifting the gut microbial composition, but no investigations have studied the effect of endurance running, such as marathon running, on human gut microbial communities. Since many findings have shown that marathon running immediately causes metabolic changes in blood, urine, muscles and lymph that potentially impact the gut microbiota (GM) within several hours. Here, we investigated whether the GM immediately responds to the enteric changes in amateur half-marathon runners. Alterations in the metabolic profile and microbiota were investigated in fecal samples based on an untargeted metabolomics methodology and 16S rDNA sequencing analysis. A total of 40 fecal metabolites were found significantly changed after finishing a half-marathon race. The most significantly different metabolites were organic acids (the major increased metabolites) and nucleic acid components (the major decreased metabolites). The enteric changes induced by running did not affect the α-diversity of the GM, but the abundances of certain microbiota members were shown to be significantly different before and after running. The family Coriobacteriaceae was identified as a potential biomarker that links exercise with health improvement. Functional prediction showed a significantly activated “Cell motility” function of GM within participants after running. Correlation analysis indicated that the observed differential GM in our study might have been the shared outcome of running and diet. This study provided knowledge regarding the health impacts of marathon running from the perspective of GM for the first time. Our data indicated that long-distance endurance running can immediately cause striking metabolic changes in the gut environment. Gut microbes can rapidly respond to the altered fecal metabolites by adjusting certain bacterial taxa. These findings highlighted the health-promoting benefits of exercise from the perspective of GM.