Study of hematological and biochemical parameters in runners completing a standard marathon

Neutrophil depletion attenuates acute renal injury after exhaustive exercise in mice

Prolonged intense exercise induces acute renal injury; however, the precise mechanism remains unclear. We investigated the effects of neutrophil depletion in male C57BL/6J mice. Male C57BL/6J mice were divided into four groups: sedentary with control antibody; sedentary with antineutrophil antibody; exhaustive exercise with control antibody; and exhaustive exercise with antineutrophil antibody. Antineutrophil (1A8) or control antibody was administered i.p. to the mice before they ran on a treadmill. Plasma levels of creatinine and blood urea nitrogen (BUN) were measured. Renal histology was assessed 24 h after exhaustive exercise, and the concentration of kidney injury molecule (KIM)-1 was measured using an enzyme-linked immunosorbent assay. The expression levels of inflammatory cytokines were measured using qRT-PCR. Furthermore, NADPH oxidase activity and the hydrogen peroxide concentration in the kidney were measured. Immediately after exhaustive exercise, plasma BUN was significantly increased, but creatinine was not. The increase in BUN after exercise was suppressed by 1A8 treatment. The pathological changes manifested as congested and swollen glomeruli and nuclear infiltration after exhaustive exercise. These changes were suppressed by treatment with the 1A8 antibodies. The KIM-1 concentration increased after exhaustive exercise but was reduced by the 1A8 antibodies. Treatment with the 1A8 antibody also decreased exhaustive exercise-induced inflammation and reactive oxygen species levels in the kidney. These results suggest that neutrophils contribute to exercise-induced acute renal injury by regulating inflammation and oxidative stress.

What is known about the health effects of non-steroidal anti-inflammatory drug (NSAID) use in marathon and ultraendurance running: a scoping review

This systematic scoping review aimed to understand the extent and scope of evidence on the health risks of non-steroidal anti-inflammatory drug (NSAID) use in marathon and ultraendurance running. NSAIDs are commonly consumed by runners to combat pain and inflammation; however, the health risks of consuming these drugs during marathon and ultrarunning events are currently not fully understood. Four databases (Cochrane Library, PubMed, MEDLINE and SPORTDiscus) were searched to identify articles focusing on running events of 26.2 miles or further, and they must have reported on the health risks of NSAID use. There was no restriction on the study design or the date of publication. Thirty studies were ultimately included: 4 randomised controlled trials, 1 cross-sectional study, 11 retrospective reviews, 4 case reports, 1 non-randomised control trial, and 9 prospective observational studies. The literature showed that potential health concerns of NSAID use could be split into five categories: electrolyte balance and hyponatraemia; acute kidney injury (AKI); gastrointestinal disturbances; oxidative stress, inflammation and muscle damage; other medical concerns. None of these sections had clear statistically significant links with NSAID use in ultraendurance running. However, potential links were shown, especially in AKI and electrolyte balance. This review suggests there is very limited evidence to show that NSAIDs have a negative impact on the health of ultrarunning athletes. Indications from a few non-randomised studies of a possible effect on kidney function need exploring with more high-quality research.

A Conspectus of Euvolemic Hyponatremia, Its Various Etiologies, and Treatment Modalities: A Comprehensive Review of the Literature

Hyponatremia is the most prevalent electrolyte imbalance encountered among hospitalized patients, athletes, the elderly, patients with chronic ailments, postoperative patients, and a few asymptomatic individuals. Clinical manifestations of hyponatremia can be diverse, with characteristic neurological symptoms. Depending on in-depth medical history, physical examination (including volume status assessment), laboratory investigation, and drug history, patients can be classified broadly as undergoing hypervolemic, euvolemic, or hypovolemic hyponatremia. However, patients with hypervolemic hyponatremia often present with distinctive signs such as edema or ascites, and the clinical presentation of hypovolemic and euvolemic hyponatremia poses significant challenges for clinicians. The convolution in clinical manifestations of patients is due to the varied etiologies of euvolemic hyponatremia, such as syndrome of inappropriate antidiuretic hormone secretion (SIADH), adrenocortical insufficiency, hypothyroidism, psychogenic polydipsia, different classes of drugs (chemotherapeutics, antipsychotics, antidepressants), endurance exercise events, and reset osmostat syndrome (ROS). The management of hyponatremia depends on the rate of hyponatremia onset, duration, severity of symptoms, levels of serum sodium, and underlying comorbidities. Over the last decade, the clinical understanding of hyponatremia has been scattered due to the introduction of innovative laboratory markers and new drugs. This article will be a conspectus of all the recent advancements in the field of diagnosis, investigations, management, and associations of hyponatremia, along with traditional clinical practices. Subsequently, a holistic overview has been laid out for the clinicians to better understand and identify knowledge deficiencies on this topic.

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.

Exercise-Associated Hyponatremia in Marathon Runners

Exercise-associated hyponatremia (EAH) was first described as water intoxication by Noakes et al. in 1985 and has become an important topic linked to several pathological conditions. However, despite progressive research, neurological disorders and even deaths due to hyponatremic encephalopathy continue to occur. Therefore, and due to the growing popularity of exercise-associated hyponatremia, this topic is of great importance for marathon runners and all professionals involved in runners' training (e.g., coaches, medical staff, nutritionists, and trainers). The present narrative review sought to evaluate the prevalence of EAH among marathon runners and to identify associated etiological and risk factors. Furthermore, the aim was to derive preventive and therapeutic action plans for marathon runners based on current evidence. The search was conducted on PubMed, Scopus and Google Scholar using a predefined search algorithm by aggregating multiple terms (marathon run; exercise; sport; EAH; electrolyte disorder; fluid balance; dehydration; sodium concentration; hyponatremia). By this criterion, 135 articles were considered for the present study. Our results revealed that a complex interaction of different factors could cause EAH, which can be differentiated into event-related (high temperatures) and person-related (female sex) risk factors. There is variation in the reported prevalence of EAH, and two major studies indicated an incidence ranging from 7 to 15% for symptomatic and asymptomatic EAH. Athletes and coaches must be aware of EAH and its related problems and take appropriate measures for both training and competition. Coaches need to educate their athletes about the early symptoms of EAH to intervene at the earliest possible stage. In addition, individual hydration strategies need to be developed for the daily training routine, ideally in regard to sweat rate and salt losses via sweat. Future studies need to investigate the correlation between the risk factors of EAH and specific subgroups of marathon runners.

Exercise-Induced Hyponatremia: An Assessment of the International Hydration Recommendations Followed During the Gran Trail De Peñalara and Vitoria-Gasteiz Ironman Competitions

Introduction

Hyponatremia often occurs during the practice of endurance sports. We evaluated the impact on hyponatremia of the hydration recommendations of the Third International Exercise-Associated Hyponatremia Consensus Development Conference 2015 (3IE-AHCD) during the 2017 Gran Trail de Peñalara marathon (GTP) and the Vitoria Gasteiz Ironman triathlon (VGI).

Methods

Prospective study of GTP and VGI athletes participating in four information sessions in the months prior to the events, to explain that hydration should only be according to their level of thirst, per the recommendations of the 3IE-AHCD. Consenting event finishers were included in final analysis. Pre- and post-race anthropometric and biochemical parameters were compared.

Results

Thirty-six GTP (33 male) and 94 VGI (88 male) finishers were evaluated. GTP race median fluid intake was 800 ml/h, with 900 ml/h in the VGI race. 83.3% GTPfin and 77.6% VGIfin remained eunatremic (blood sodium 135–145 mmol/L). Only 1/36 GTP and 1/94 VGI participant finished in hyponatremia, both with a sodium level of 134 mmol/L. Fourteen percent of GTP, and 21.2% of VGI participants finished in hypernatremia, with no increase in race completion times. No participating athlete required medical attention, except for musculoskeletal complaints. Pro-BNP and Copeptin levels rose significantly. Changes in copeptin levels did not correlate with changes in plasma osmolality, nor total body water content in impedance analysis.

Conclusions

Recommending that athletes' fluid intake in endurance events be a function of their thirst almost entirely prevented development of hyponatremia, without induction of clinically significant hypernatremia, or a negative repercussion on race completion times.

Involvement of G-CSF, IL-6, and cortisol in transient neutrophilia after marathon races

OBJECTIVES

The aim of this study was to clarify the mechanisms of the transient increase in neutrophils after running standard marathon races by measurement of cytokines involved in the production and survival of neutrophils, and cortisol.

METHODS

Fourteen male runners who participated in the Hokkaido Marathon, which is the sole marathon race held in summer in Japan, and finished the standard marathon were analyzed sequentially from the start until a maximum of 8 days after the finish.

RESULTS

Neutrophilia was observed in all runners just after they reached the goal (mean neutrophils: 13 226/μL). IL-6, G-CSF, and cortisol, but not GM-CSF, increased at the same time. Time-course studies with complete blood counts, biochemical markers, cytokines, and cortisol showed transient increases in neutrophils, monocytes, myoglobin, high-sensitivity C-reactive protein (hsCRP), G-CSF, IL-6, and cortisol. The increase in hsCRP was delayed 6 hours from the first increase in neutrophils. Correlations were observed between the neutrophil count and G-CSF, IL-6, and cortisol (G-CSF; r = .667, IL-6; r = .667, cortisol; r = .623).

CONCLUSION

These results suggest that G-CSF is directly involved, and IL-6 is involved via cortisol in the transient neutrophilia that occurs after marathon races.

Exercise under heat stress: thermoregulation, hydration, performance implications, and mitigation strategies

A rise in body core temperature and loss of body water via sweating are natural consequences of prolonged exercise in the heat. This review provides a comprehensive and integrative overview of how the human body responds to exercise under heat stress and the countermeasures that can be adopted to enhance aerobic performance under such environmental conditions. The fundamental concepts and physiological processes associated with thermoregulation and fluid balance are initially described, followed by a summary of methods to determine thermal strain and hydration status. An outline is provided on how exercise-heat stress disrupts these homeostatic processes, leading to hyperthermia, hypohydration, sodium disturbances, and in some cases exertional heat illness. The impact of heat stress on human performance is also examined, including the underlying physiological mechanisms that mediate the impairment of exercise performance. Similarly, the influence of hydration status on performance in the heat and how systemic and peripheral hemodynamic adjustments contribute to fatigue development is elucidated. This review also discusses strategies to mitigate the effects of hyperthermia and hypohydration on exercise performance in the heat by examining the benefits of heat acclimation, cooling strategies, and hyperhydration. Finally, contemporary controversies are summarized and future research directions are provided.

Association between collapse and serum creatinine and electrolyte concentrations in marathon runners: a 9-year retrospective study

OBJECTIVE

Abnormal biochemical measurements have previously been described in runners following marathons. The incidence of plasma sodium levels outside the normal range has been reported as 31%, and the incidence of raised creatinine at 30%. This study describes the changes seen in electrolytes and creatinine in collapsed (2010-2019 events) and noncollapsed (during the 2019 event) runners during a UK marathon.

METHODS

Point-of-care sodium, potassium, urea and creatinine estimates were obtained from any collapsed runner treated by the medical team during the Brighton Marathons, as part of their clinical care, and laboratory measurements from control subjects.

RESULTS

Results from 224 collapsed runners were available. Serum creatinine was greater than the normal range in 68.9%. About 6% of sodium results were below, and 3% above the normal range, with the lowest 132 mmol/l. Seventeen percent of potassium readings were above the normal range; the maximum result was 8.4 mmol/l, but 97% were below 6.0 mmol/l. In the control group, mean creatinine was significantly raised in both the collapse and control groups, with 55.4% meeting the criteria for acute kidney injury, but had resolved to baseline after 24 h. Sodium concentration but not the potassium was significantly raised after the race compared with baseline, but only 15% were outside the normal range.

CONCLUSION

In this study, incidence of a raised creatinine was higher than previously reported. However, the significance of such a rise remains unclear with a similar rise seen in collapsed and noncollapsed runners, and resolution noted within 24 h. Abnormal sodium concentrations were observed infrequently, and severely abnormal results were not seen, potentially reflecting current advice to drink enough fluid to quench thirst.

Altered GDF15 and FGF21 Levels in Response to Strenuous Exercise: A Study in Marathon Runners

Background

Recreational marathon runners face strong physiological challenges. Assessment of potential biomarkers for the biological responses of runners will help to discriminate individual race responsiveness and their physiological consequences. This study sought to analyze the changes in the plasma levels of GDF15 and FGF21, novel endocrine factors related to metabolic stress, in runners following the strenuous exercise of a marathon race.

Methods

Blood samples were obtained from eighteen male runners (mean ±SD, age: 41.7 ±5.0 years, BMI: 23.6 ± 1.8) 48 h before, immediately after, and 48 h after a marathon race, and from age-matched sedentary individuals. The level of GDF15, FGF21, and 38 additional biochemical and hematological parameters were determined.

Results

The basal levels of GDF15 and FGF21 did not differ between runners before the race and sedentary individuals. Significant increases in the mean levels of GDF15 (4.2-fold) and FGF21 (20-fold) were found in runners immediately after the race. The magnitudes of these increases differed markedly among individuals and did not correlate with each other. The GDF15 and FGF21 levels had returned to the basal level 48 h post-race. The post-race value of GDF15 (but not FGF21) correlated positively with increased total white cell count (r = 0.50, P = 0.01) and neutrophilia (r = 0.10, P = 0.01).

Conclusion

GDF15 and FGF21 are transiently increased in runners following a marathon race. The induction of GDF15 levels is associated with alterations in circulating immune cells levels.

Oral non-steroidal anti-inflammatory drug use in recreational runners participating in Parkrun UK: Prevalence of use and awareness of risk

Objective

Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used in endurance running and by elite athletes. We examined the pattern of use of NSAIDs, the purpose of use and knowledge of the adverse effects of NSAID use in a population of recreational runners at Parkrun UK.

Methods

An online observational non-interventional cross-sectional survey of Parkrun UK participants being over the age of 18, on Parkrun UK’s mailing list, and residing in the UK.

Key Findings

Runners (n = 806) had a high use of NSAIDs in the past 12 months (87.8%). The average age of respondents was 48.39 years. There was a significant association between those taking an oral NSAID in the last twelve months and those with a sporting injury (χ2 = 10.89, df = 1, n = 797, P = 0.001). Ibuprofen was the most commonly used NSAID (81.1%). A third of runners had experienced an adverse drug reaction associated with NSAIDs, usually gastrointestinal. Half of runners used NSAIDs with no advice, and patient information leaflets were the most common source for those that had advice. Ninety-four per cent of runners would like more information on the harms and benefits of NSAIDs.

Conclusions

Some recreational runners have a high use of NSAIDs, which is chronic in nature and a potential health risk. Recreational runners want more information on the harms and benefits of NSAIDs. Race event organizers should provide evidence-based advice on the use of NSAIDs.

Heat Stress Challenges in Marathon vs. Ultra-Endurance Running

Several studies have investigated the effect of hot and humid ambient conditions on running exercise up to the marathon. However, studies on exercise longer than marathon are sparse. Events exceeding 6 h can be defined as ultra-endurance and have variable characteristics (e.g., distance, elevation profile, technical difficulty, altitude, night running) making hazardous the transposition of the current knowledge obtained in marathon to ultra-endurance running. Thus, the aim of this manuscript was to discuss the potential differences between marathon and ultra-endurance running in terms of heat stress challenges. The high running intensity (especially for the fastest runners), the urban context with high albedo effect materials, and the hot self-generated microclimate in mass-participation events (especially for the average to slow runners) are specific risk factors associated with marathon running in hot environments. Uphill running/walking (sometimes with poles), exotic destination with long-haul travel, desert environment and the necessity to sustain thermoregulatory and sweating responses for several days are risk factors more specific to ultra-endurance running. These differences call for specific research on the effect of hot ambient conditions in ultra-endurance disciplines to create appropriate recommendations.

Exercise-Associated Hyponatremia in Endurance and Ultra-Endurance Performance-Aspects of Sex, Race Location, Ambient Temperature, Sports Discipline, and Length of Performance: A Narrative Review

Exercise-associated hyponatremia (EAH) is defined as a plasma sodium concentration of <135 mmol/L during or after endurance and ultra-endurance performance and was first described by Timothy Noakes when observed in ultra-marathoners competing in the Comrades Marathon in South Africa in the mid-1980s. It is well-established that a decrease in plasma sodium concentration <135 mmol/L occurs with excessive fluid intake. Clinically, a mild hyponatremia will lead to no or very unspecific symptoms. A pronounced hyponatremia (<120 mmol/L) will lead to central nervous symptoms due to cerebral edema, and respiratory failure can lead to death when plasma sodium concentration reaches values of <110-115 mmol/L. The objective of this narrative review is to present new findings about the aspects of sex, race location, sports discipline, and length of performance. The prevalence of EAH depends on the duration of an endurance performance (i.e., low in marathon running, high to very high in ultra-marathon running), the sports discipline (i.e., rather rare in cycling, more frequent in running and triathlon, and very frequent in swimming), sex (i.e., increased in women with several reported deaths), the ambient temperature (i.e., very high in hot temperatures) and the country where competition takes place (i.e., very common in the USA, very little in Europe, practically never in Africa, Asia, and Oceania). A possible explanation for the increased prevalence of EAH in women could be the so-called Varon-Ayus syndrome with severe hyponatremia, lung and cerebral edema, which was first observed in marathon runners. Regarding the race location, races in Europe seemed to be held under rather moderate conditions whereas races held in the USA were often performed under thermally stressing conditions (i.e., greater heat or greater cold).

[Exercise-Associated Hyponatremia in Endurance Performance]

Exercise-Associated Hyponatremia in Endurance Performance Abstract. Exercise-associated hyponatremia is defined as a plasma sodium concentration of <135 mmol/l and was first described by Timothy Noakes at the Comrades Marathon in South Africa in the mid-1980s. A decrease in plasma sodium <135 mmol/l occurs with excessive fluid intake. Risk factors include long to very long endurance performance, extreme climatic conditions, female gender and competitions in the USA. Regarding its prevalence by sport, exercise-associated hyponatraemia tends to occur while swimming and running, but rarely when cycling. While mild exercise-associated hyponatremia does not lead to clinical symptoms, severe hyponatremia due to cerebral edema can lead to neurological deficits and even death. The best prevention of exercise-associated hyponatremia is the reduction of fluid intake during exercise.

Winning at all costs: a review of risk-taking behaviour and sporting injury from an occupational safety and health perspective

Professional athletes involved in high-performance sport are at a high injury risk, which may lead to long-term health consequences. Professional athletes often expose themselves to risky behaviours, resulting in a higher acceptance level of occupational risk compared to other occupations. To date, many studies have focused on elite athletes' specific injury prevention techniques. The objective of this narrative review is to (1) summarise elite athletes' attitudes towards important occupational safety and health (OSH) practices, including injury reporting, medicine usage and personal protective equipment (PPE) usage, and (2) explore factors that may influence elite athletes' injury awareness. If injury awareness were given a similar weighting in elite sports as in any other highly physical occupation, the potential benefits to elite athletes and their long-term health could be highly significant. This review identifies that most elite athletes are not aware that sporting injuries are occupational injuries requiring behaviours determined by OSH rules. All the 39 studies identified met the moderate methodological quality criteria according to the Mixed Methods Appraisal Tool (MMAT). The factors impeding athletes' injury awareness from achieving occupational health standards are discussed from three safety management perspectives: organisational, societal and individual. This review contributes to a better understanding of how to build a positive safety culture, one that could reduce elite athletes' injury rate and improve their long-term wellbeing. Further research is required to develop a quantitative measurement instrument to evaluate occupational health awareness in the sport context. Based on the papers reviewed, the study population was categorised as elite, professional, high-performance amateur and student-athletes.

Winning at all costs: a review of risk-taking behaviour and sporting injury from an occupational safety and health perspective

Professional athletes involved in high-performance sport are at a high injury risk, which may lead to long-term health consequences. Professional athletes often expose themselves to risky behaviours, resulting in a higher acceptance level of occupational risk compared to other occupations. To date, many studies have focused on elite athletes' specific injury prevention techniques. The objective of this narrative review is to (1) summarise elite athletes' attitudes towards important occupational safety and health (OSH) practices, including injury reporting, medicine usage and personal protective equipment (PPE) usage, and (2) explore factors that may influence elite athletes' injury awareness. If injury awareness were given a similar weighting in elite sports as in any other highly physical occupation, the potential benefits to elite athletes and their long-term health could be highly significant. This review identifies that most elite athletes are not aware that sporting injuries are occupational injuries requiring behaviours determined by OSH rules. All the 39 studies identified met the moderate methodological quality criteria according to the Mixed Methods Appraisal Tool (MMAT). The factors impeding athletes' injury awareness from achieving occupational health standards are discussed from three safety management perspectives: organisational, societal and individual. This review contributes to a better understanding of how to build a positive safety culture, one that could reduce elite athletes' injury rate and improve their long-term wellbeing. Further research is required to develop a quantitative measurement instrument to evaluate occupational health awareness in the sport context. Based on the papers reviewed, the study population was categorised as elite, professional, high-performance amateur and student-athletes.

Exercise-Associated Hyponatremia During a Self-Paced Marathon Attempt in a 15-Year-Old Male Teenager

Background and objective: The increased participation in endurance sports such as marathon running has attracted scientific interest especially with regard to adult athletes. However, few studies have examined the impact of a marathon race on children and adolescents. Therefore, the aim of the present case study was two-fold: first, to describe pacing during a marathon race, and second, to examine acute responses of blood physiology and biochemistry parameters during the race (i.e., pre- and post-race) as well as five consecutive days after the race. Materials and Methods: Participant was a 15-year-old boy who completed a self-paced marathon attempt for the first time and finished in 5 h 19 m 53 s. Positive pacing (i.e., a running speed that decreased throughout race) with a final end spurt was observed. Results: An increase in fluid intake across race was shown. Exercise-associated hyponatremia (EAH, i.e., plasma sodium concentration <135 mmol/L) was found post-race. C-reactive protein (CRP) did not correlate either with creatine kinase (CK) (r = 0.457, p = 0.302) or with lactate dehydrogenase (LDH) (r = 0.156, p = 0.739); however, leukocytes correlated very largely with LDH (r = 0.889, p = 0.007) but not with CK (r = 0.696, p = 0.082). CK and LDH related almost perfectly with creatinine (r = 0.937, p = 0.002 and r = 0.959, p = 0.001, respectively); also, creatinine clearance correlated very largely with CK (r = −0.782, p = 0.038) but not with LDH (r = −0.733, p = 0.061). Leukocytes, aspartate aminotransferase, LDH, and CK deviated from physiological range post-race, but returned to normal values during the five-day recovery period. Conclusions: In summary, a male teenager at the age of 15 years was able to run a marathon in under 6 h without significant harmful effects on health. He developed mild and asymptomatic EAH and an increase in leucocytes, CRP, CK, and LDH as markers of inflammation and skeletal muscle damage. EAH after the marathon was resolved within one day of recovery.

Amateur endurance athletes’ use of non-steroidal anti-inflammatory drugs: a cross-sectional survey

Objective

To explore amateur endurance athletes’ use and views about non-steroidal anti-inflammatory drugs (NSAIDs).

Methods

An online cross-sectional survey of amateur athletes at four athletic clubs.

Key findings

Of a sample of 129 of amateur athletes, 68% (n = 88) reported using NSAIDs in the previous 12 months (84.4% in triathletes, 70.9% in runners and 52.5% in cyclists). Overall, ibuprofen was the most popular drug (n = 48). There was a lack of knowledge of adverse drug reactions, with only 26% of use advised by a doctor or pharmacist.

Conclusions

There is high usage of NSAIDs in amateur athletes, including before and during events, largely without professional health advice. Informational needs of amateur athletes are not being met.

Exercise-Associated Hyponatremia: A Local Case Report

Most of us know the risk of dehydration during endurance exercise under extreme heat. We report a case that occurred in cool weather and when there was an abundant supply of fluid – the so-called exercise-associated hyponatremia. It is a potentially life-threatening condition and has led to at least seven fatal outcomes reported in the literature.

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.

Exercise-Associated Hyponatremia: 2017 Update

Exercise-associated hyponatremia (EAH) was initially described in the 1980s in endurance athletes, and work done since then has conclusively identified that overdrinking beyond thirst and non-osmotic arginine vasopressin release are the most common etiologic factors. In recent years, EAH has been described in a broader variety of athletic events and also has been linked to the development of rhabdomyolysis. The potential role of volume and sodium depletion in a subset of athletes has also been described. This review focuses on the most recent literature in the field of EAH and summarizes key new findings in the epidemiology, pathophysiology, treatment, and prevention of this condition.

Use of Non-Steroidal Anti-Inflammatory Drugs among Participants in a Mountain Ultramarathon Event

The aim of this study was to evaluate and compare the prevalence of non-steroidal anti-inflammatory drugs (NSAID) consumption immediately before, during and immediately after three mountain ultra-endurance runs that differed in their course distance. This observational study took place at the Ultra Mallorca Serra de Tramuntana (Mallorca, Spain), an ultra-endurance mountain event with runners participating either in a 112-km (Ultra, n = 58), a 67-km (Trail, n = 118) or a 44-km (Marathon, n = 62) run competition. Participants in the study answered, within an hour after finishing the competition, a questionnaire focused mainly on NSAIDs consumption. Among study participants, 48.3% reported taking NSAIDs at least for one of the time-points considered: before, during and/or immediately after the competition, with more positive responses (having taken medication) found for the Ultra (60.3%) than for the Trail (49.2%) and the Marathon (35.5%). Among consumers, the Ultra participants reported the lowest intake before and the highest during the race, while participants in the Marathon reported similar consumption levels before and during the race. In conclusion, a high prevalence of NSAID consumption was found among athletes participating in an ultra-endurance mountain event. Competition duration seemed to determine both the prevalence and the chronological pattern of NSAID consumption.

Substance use and misuse in a mountain ultramarathon: new insight into ultrarunners population?

Endurance and ultra-endurance events have become increasingly popular. The aim of our study was to explore the use of medication among endurance runners participating in the 2014 Infernal Trail des Vosges. Among the 389 runners engaged, 297 (76.3%) completed a specific questionnaire dealing with substance use/misuse. Our results show a 27% (before the race) and 18% (during the race) prevalence of substance use. The two major classes of substances used were non-steroidal anti-inflammatory drugs (NSAIDs; 9.8%) and painkillers (6.7%), principally because of osteo-articular pain (29.6%) or to prevent pain (28.2%). A positive correlation was found between substance consumption before (past month) and during the race (overall medication: p < 0.0001; NSAIDs: p = 0.008). Our results could be explained by the specific characteristics of ultrarunners predominantly motivated by personal achievement and general health (recreational approach). However, education interventions should further be delivered regarding the risks of substance use in ultra-endurance events.

Marathon Race Affects Neutrophil Surface Molecules: Role of Inflammatory Mediators

The fatigue induced by marathon races was observed in terms of inflammatory and immunological outcomes. Neutrophil survival and activation are essential for inflammation resolution and contributes directly to the pathogenesis of many infectious and inflammatory conditions. The aim of this study was to investigate the effect of marathon races on surface molecules related to neutrophil adhesion and extrinsic apoptosis pathway and its association with inflammatory markers. We evaluated 23 trained male runners at the São Paulo International Marathon 2013. The following components were measured: hematological and inflammatory mediators, muscle damage markers, and neutrophil function. The marathon race induced an increased leukocyte and neutrophil counts; creatine kinase (CK), lactate dehydrogenase (LDH), CK-MB, interleukin (IL)-6, IL-10, and IL-8 levels. C-reactive protein (CRP), IL-12, and tumor necrosis factor (TNF)-α plasma concentrations were significantly higher 24 h and 72 h after the marathon race. Hemoglobin and hematocrit levels decreased 72 h after the marathon race. We also observed an increased intercellular adhesion molecule-1 (ICAM-1) expression and decreasedTNF receptor-1 (TNFR1) expression immediately after and 24 h after the marathon race. We observed an increased DNA fragmentation and L-selectin and Fas receptor expressions in the recovery period, indicating a possible slow rolling phase and delayed neutrophil activation and apoptosis. Marathon racing affects neutrophils adhesion and survival in the course of inflammation, supporting the “open-window” post-exercise hypothesis.

Investigating the Cellular and Metabolic Responses of World-Class Canoeists Training: A Sportomics Approach

(1) Background: We have been using the Sportomics approach to evaluate biochemical and hematological changes in response to exercise. The aim of this study was to evaluate the metabolic and hematologic responses of world-class canoeists during a training session; (2) Methods: Blood samples were taken at different points and analyzed for their hematological properties, activities of selected enzymes, hormones, and metabolites; (3) Results: Muscle stress biomarkers were elevated in response to exercise which correlated with modifications in the profile of white blood cells, where a leukocyte rise was observed after the canoe session. These results were accompanied by an increase in other exercise intensity parameters such as lactatemia and ammonemia. Adrenocorticotropic hormone and cortisol increased during the exercise sessions. The acute rise in both erythrocytes and white blood profile were probably due to muscle cell damage, rather than hepatocyte integrity impairment; (4) Conclusion: The cellular and metabolic responses found here, together with effective nutrition support, are crucial to understanding the effects of exercise in order to assist in the creation of new training and recovery planning. Also we show that Sportomics is a primal tool for training management and performance improvement, as well as to the understanding of metabolic response to exercise.

Leukocytosis and Leukemia

Leukocytosis is among the most common findings on peripheral blood smear. A wide range of causes may mediate this finding, and careful clinical and laboratory evaluation assist in differentiating between benign and malignant causes of increased white blood cell counts. In this article, various nonmalignant causes are explored, including infectious, inflammatory, autoimmune, and allergic. In addition, malignant causes of leukocytosis are discussed, including myeloproliferative disorders, acute leukemia, and chronic leukemia, as well as treatment and monitoring for patients with these diseases.

Non-professional marathon running: RAGE axis and ST2 family changes in relation to open-window effect, inflammation and renal function

Conflicting data exist on the relevance of marathon (M) and half marathon (HM) running for health. The number of non-professional athletes finishing M and HM events is steadily growing. In order to investigate molecular changes occurring in amateur athletes, we enrolled 70 non-professional runners finishing a single M (34) or HM (36) event at baseline, the finish line and during recovery, and 30 controls. The measurement of the Receptor for Advanced Glycation Endproducts, Interleukin 1 receptor antagonist, ST2 and cytokeratin 18 was combined with molecules measured during clinical routine. Results were analyzed in the light of blood cell analysis, lactate measurements, correction for changes in plasma volume and body composition assessments. There were intrinsic differences in body mass index, abdominal body fat percentage and training time between M and HM runners. C-reactive protein changes in M and HM runners. While soluble RAGE, AGEs and ST2 increased immediately after the race in HM runners, HMGB1 increased in HM and M after the race and declined to baseline after a recovery period. We give insights into the regulation of various molecules involved in physical stress reactions and their possible implications for the cardiovascular system or renal function.

Incidence and Prevalence of Acute Kidney Injury During Multistage Ultramarathons

OBJECTIVE

Determine prevalence, incidence, and risk factors of acute kidney injury (AKI) during multistage ultramarathons.

DESIGN

Prospective observational cohort study.

SETTING

Jordanian Desert 2012; Atacama Desert, Chile 2012 and 2013; and Gobi Desert 2013 RacingThePlanet 250 km, 6-stage, ultramarathons.

PARTICIPANTS

One hundred twenty-eight participants (384 measurements) from the Jordan (25, 19.5%), Gobi (35, 27.3%), 2012 Atacama (24, 18.8%), and 2013 Atacama (44, 34.4%) races.

INTERVENTIONS

Blood samples and weights were gathered and analyzed immediately after stage 1 (40 km), 3 (120 km), and 5 (225 km).

MAIN OUTCOME MEASURES

Changes in serum creatinine (Cr), cumulative incidence, and prevalence of AKI were calculated for each stage with "risk of injury" defined as 1.5 × baseline Cr and "injury" defined as 2 × Cr.

RESULTS

Cumulative incidence of AKI was 41.4%. Stage 1 had 56 (43.8%) with risk of AKI and 24 (18.8%) with injury; in stage 3, 61 (47.7%) were at risk, 41 (32%) had injury; in stage 5, 62 (48.4%) runners were at risk and 36 (28.1%) had injury. Acute kidney injury was significantly associated with females [odds ratio (OR), 4.64; 95% confidence interval (CI), 2.07-10.37; P < 0.001], lower pack weight (OR, 0.71; 95% CI, 0.56-0.91; P < 0.007), and percentage weight loss (OR, 0.87; 95% CI, 0.78-0.97; P < 0.015). Lowest quintile of finishers was less likely to develop AKI (OR, 0.18; 95% CI, 0.04-0.78; P < 0.022).

CONCLUSIONS

Prevalence of AKI was 63%-78% during multistage ultramarathons. Female sex, lower pack weight, and greater weight loss were associated with renal impairment.

Effect of taking dietary supplement on hematological and biochemical parameters in male bodybuilders an equation model

Background:

The improved physical action following administration of supplements to bodybuilders was supported by changes in laboratory parameters. Despite the fact that these supplements are sometimes associated both advantage and side effects, this study were conducted for the purpose of evaluating the possible effects of some commonly used supplements in bodybuilders on the hematological and biochemical parameters.

Materials and Methods:

In this study, we included 40 male bodybuilders as cases and 40 controls in the age group of 20-40 years. They used different kinds of supplements for 1 year. In general, all the supplements used were classified into two groups: hormonal and non-hormonal. Laboratory tests were requested for evaluation of hematological and biochemical parameters.

Results:

In an equation model, we found that weight (P = 0.024), duration of bodybuilding (P < 0.001), and duration of hormone supplement consumption (P < 0.001) were loaded significantly on the latent variables, demographic and dietary supplement, respectively. The relationship between dietary supplement and biochemical and hematological parameters was significant (P = 0.01) and some of these parameters including creatinine (P = 0.023), blood aspartate aminotransferase (AST) (P < 0.001), alanine aminotransferase (ALT) (P < 0.001), and red blood cell distribution (RDW) (P = 0.046) had a significant role than others. In a multivariate regression model, we found that WBC (P < 0.001), platelets (P < 0.001), blood urea nitrogen (BUN; P < 0.001), creatinine (P < 0.001), AST (P = 0.005), and ALT (P = 0.001) were higher in athletes than in controls.

Conclusions:

It is strongly advised that there should be some concerns about possible supplement-induced changes in the laboratory exams for bodybuilders. The available supplements are unchecked and not approved by the US Food and Drug Administration (FDA). More studies should be designed for a better and precise administration of each supplement in athletes.

Ginger (Zingiber officinale) as an Analgesic and Ergogenic Aid in Sport: A Systemic Review

Ginger is a popular spice used to treat a variety of maladies, including pain. Nonsteroidal anti-inflammatory drugs (NSAIDs) are frequently used by athletes to manage and prevent pain; unfortunately, NSAIDs contribute to substantial adverse effects, including gastrointestinal (GI) dysfunction, exercise-induced bronchoconstriction, hyponatremia, impairment of connective tissue remodeling, endurance competition withdrawal, and cardiovascular disease. Ginger, however, may act as a promoter of GI integrity and as a bronchodilator. Given these potentially positive effects of ginger, a systematic review of randomized trials was performed to assess the evidence for ginger as an analgesic and ergogenic aid for exercise training and sport. Among 7 studies examining ginger as an analgesic, the evidence indicates that roughly 2 g·d(-1) of ginger may modestly reduce muscle pain stemming from eccentric resistance exercise and prolonged running, particularly if taken for a minimum of 5 days. Among 9 studies examining ginger as an ergogenic aid, no discernable effects on body composition, metabolic rate, oxygen consumption, isometric force generation, or perceived exertion were observed. Limited data suggest that ginger may accelerate recovery of maximal strength after eccentric resistance exercise and reduce the inflammatory response to cardiorespiratory exercise. Major limitations to the research include the use of untrained individuals, insufficient reporting on adverse events, and no direct comparisons with NSAID ingestion. While ginger taken over 1-2 weeks may reduce pain from eccentric resistance exercise and prolonged running, more research is needed to evaluate its safety and efficacy as an analgesic for a wide range of athletic endeavors.

Body Weight, Serum Sodium Levels, and Renal Function in an Ultra-Distance Mountain Run

OBJECTIVE

To determine body weight and serum [Na] changes in runners completing an 85-km mountain run, particularly with reference to their "in-race" hydration protocols.

DESIGN

Prospective observational cohort study.

SETTING

Cradle Mountain Run, Tasmania, Australia, February 2011.

PARTICIPANTS

Forty-four runners (86% of starters) prospectively enrolled, with 41 runners (80% of starters) eligible for inclusion in final data set.

MAIN OUTCOME MEASURES

Body weight change, serum sodium concentration change, and hydration plan (according to thirst vs preplanned fluid consumption).

RESULTS

There was 1 case of exercise-associated hyponatremia (EAH) [postrace [Na], 132 mmol/L]. This runner was asymptomatic. There was a strongly significant correlation between the change in serum [Na] and body weight change during the race. There was a significant inverse correlation between serum [Na] and volume of fluid consumed. Change of serum [Na] was not correlated with the proportion of water versus electrolyte drink consumed. Runners drinking to thirst consumed significantly lower average fluid volumes and had higher postrace serum [Na] than those complying with a preplanned hydration protocol (142 mmol/L vs 139 mmol/L). More experienced runners tended to drink to thirst.

CONCLUSIONS

There was a 2% incidence of EAH in this study. Serum [Na] change during an 85-km mountain run was inversely correlated with the volume of fluid consumed. The results provide further evidence that EAH is a dilutional hyponatremia caused by excessive consumption of hypotonic fluids. Drinking to thirst represents a safe hydration strategy for runners in a wilderness environment.

CLINICAL RELEVANCE

Drinking to thirst during endurance running events should be promoted as a safe hydration practice.

Investigation of Sudden Death in Athletes: The Fittest Bodies in the Morgue

Sporting events are generally viewed as regulated activities with fit and healthy participants; therefore, when deaths occur, they draw considerable public interest. Athletic participants can be considered a vulnerable population based on inherent risks within certain sports and the associated physiologic stresses, which may complicate underlying medical conditions. Sudden deaths in young athletes participating in high school and collegiate organized sports occur at an average of four to six deaths per year; however, sudden deaths related to exercise outside of an organized sport setting remain unaccounted for in the overall prevalence of these deaths. A typical forensic pathology practice will see not only these higher-profile deaths occurring during an organized sporting event, but also lower-profile occurrences of individuals dying during more recreational or unstructured exercise. Sport-related deaths can essentially be categorized as those that occur due to dangers inherent in the sport itself, such as forms of heat-related illnesses, blunt force trauma, and water-related deaths, and those that occur due to susceptibilities of a given predisposed participant, including sickle cell trait, hypertrophic cardiomyopathy, and other cardiovascular diseases. This article will address both types of vulnerabilities and provide guidance for appropriate and specific medicolegal death investigation and autopsy procedures in these deaths.

The prevalence of exercise-associated hyponatremia in 24-hour ultra-mountain bikers, 24-hour ultra-runners and multi-stage ultra-mountain bikers in the Czech Republic

BACKGROUND

To assess the prevalence of exercise-associated hyponatremia (EAH) in two 24-hour mountain bike (MTB) (R1,R2), one 24-hour running (R3) and one multi-stage MTB (R4) races held in the Czech Republic in a cluster of four cross-sectional studies.

METHODS

In 27 ultra-mountain bikers (ultra-MTBers), 12 ultra-runners, and 14 multi-stage MTBers, fluid intake, changes (Δ) in body mass, hematocrit, plasma volume, plasma [Na+], plasma [K+], plasma osmolality, urine [Na+], urine [K+], urine specific gravity, urine osmolality, K+/Na+ ratio in urine, transtubular potassium gradient and glomerular filtration rate were measured and calculated. The use of non-steroidal anti-inflammatory drugs and symptoms of EAH were recorded using post-race questionnaires.

RESULTS

Of the 53 finishers, three (5.7%) developed post-race EAH, thereof one (3.7%) ultra-MTBer, one (8.3%) ultra-runner and one (7.1%) multi-stage MTBer. Plasma [Na+] decreased significantly (p < 0.001) only in R4. Urine osmolality (R1, R3, R4 p < 0.001; R2 p < 0.05) and glomerular filtration rate (p < 0.001) increased, and body mass decreased in all races (p < 0.05). Δ body mass was inversely related to the number of kilometers achieved (p < 0.001) in R2 where better ultra-MTBers tended to lose more weight. Δ body mass (p < 0.001) and %Δ body mass (p = 0.05) were positively related to lower post-race plasma [Na+] in R3 that was associated with increased loss in body mass. Fluid intake was positively related to race performance in R1 and R2 (R1: p = 0.04; R2: p = 0.01) where ultra-MTBers in R1 and R2 who drank more finished ahead of those who drank less. Post-race plasma [Na+] was negatively associated with race performance in ultra-MTBers in R2 (p < 0.05), similarly ultra-runners in R3 (p < 0.05) where finishers with more kilometres had lower post-race plasma [Na+].

CONCLUSIONS

The prevalence of EAH in the Czech Republic was no higher compared to existing reports on ultra-endurance athletes in other countries. Lower plasma [Na+] and development of EAH may be attributed to overdrinking, a pituitary secretion of vasopressin, an impaired mobilization of osmotically inactive sodium stores, and/or an inappropriate inactivation of osmotically active sodium.

Acute changes to biomarkers as a consequence of prolonged strenuous running

BACKGROUND

A single bout of strenuous running exercise results in perturbations to numerous biomarkers. An understanding of these is important when analysing samples from individuals who have recently performed such exercise.

METHODS

A literature search was undertaken using the search terms, exercise, marathon and delayed onset of muscle soreness. The search was then refined using the terms for key biomarkers known to be altered by exercise.

RESULTS

The magnitude of changes to biomarkers is proportional to the severity of the running bout. Familiar, moderate intensity running exercise produces brief transient changes in common biomarkers such as lactate, whereas more severe bouts of running exercise, such as marathons and ultra-marathon events can produce changes to biomarkers that are normally associated with pathology of the muscles, liver and heart. Examples being changes to concentrations and/or activity of myoglobin, leucocytes, creatine kinase, bilirubin, cardiac troponins, lactate dehydrogenase, alanine aminotransferase and aspartate aminotransferase. While persisting for longer, these changes are also transient and full recovery occurs within days, without any apparent long-term adverse consequences. Additionally, unfamiliar exercise involving forceful eccentric muscle contractions, such as running downhill, can cause increases in creatine kinase and delayed onset of muscle soreness that peaks 36-72 h after the exercise bout.

CONCLUSIONS

Strenuous running exercise can produce changes to biomarkers that are normally associated with disease and injury, but these do not necessarily reflect chronic pathology.

Urine dipstick analysis for identification of runners susceptible to acute kidney injury following an ultramarathon

This study examined whether urine dipstick testing might be useful to predict the development of acute kidney injury after an ultramarathon. Participants in the 2011 161-km Western States Endurance Run underwent post-race blood and urine dipstick analyses. Of the 310 race finishers, post-race urine dipstick testing was completed on 152 (49%) and post-race blood also was obtained from 150 of those runners. Based on "injury" and "risk" criteria for acute kidney injury of blood creatinine 2.0 and 1.5 times estimated baseline, respectively, 4% met the criteria for injury and an additional 29-30% met the criteria for risk of injury. Those meeting the injury criteria had higher creatine kinase concentrations (P < 0.001) than those not meeting the criteria. Urine dipstick tests that read positive for at least 1+ protein, 3+ blood, and specific gravity ≥ 1.025 predicted those meeting the injury criteria with sensitivity of 1.00 (95% confidence interval [CI] 0.54-1.00), specificity of 0.76 (95% CI 0.69-0.83), positive predictive value of 0.15 (95% CI 0.06-0.30), negative predictive value of 1.00 (95% CI 0.97-1.00), and likelihood ratio for a positive test of 4.2. We conclude that urine dipstick testing was successfully able to identify those individuals meeting injury criteria for acute kidney injury with excellent sensitivity and specificity.

Prevalence of hyponatremia, renal dysfunction, and other electrolyte abnormalities among runners before and after completing a marathon or half marathon

Background:

Prior reports on metabolic derangements observed in distance running frequently have small sample sizes, lack prerace laboratory measures, and report sodium as the sole measure.

Hypothesis:

Metabolic abnormalities—hyponatremia, hypokalemia, renal dysfunction, hemoconcentration—are frequent after completing a full or half marathon. Clinically significant changes occur in these laboratory values after race completion.

Study Design:

Observational, cross-sectional study.

Methods:

Consenting marathon and half marathon racers completed a survey as well as finger stick blood sampling on race day of the National Marathon to Fight Breast Cancer (Jacksonville, Florida, February 2008). Parallel blood measures were obtained before and after race completion (prerace, n = 161; postrace, n = 195).

Results:

The prevalence of prerace and postrace hyponatremia was 8 of 161 (5.0%) and 16 of 195 (8.2%), respectively. Hypokalemia was not present prerace but was present in 1 runner postrace (1 of 195). Renal dysfunction occurred prerace in 14 of 161 (8.7%) and postrace in 83 of 195 (42.6%). Among those with postrace renal dysfunction, 45.8% (38 of 83) were classified as moderate or severe. Hemoconcentration was present in 2 of 161 (1.2%) prerace and 6 of 195 (3.1%) postrace. The mean changes in laboratory values were (postrace minus prerace): sodium, 1.6 mmol/L; potassium, −0.2 mmol/L; blood urea nitrogen, 2.8 mg/dL; creatinine, 0.2 mg/dL; and hemoglobin, 0.3 g/dL for 149 pairs (except blood urea nitrogen, n = 147 pairs). Changes were significant for all comparisons (P < 0.01) except potassium (P = 0.08) and hemoglobin (P = 0.01).

Conclusions:

Metabolic abnormalities are common among endurance racers, and they may be present prerace, including hyponatremia. The clinical significance of these findings is unknown.

Clinical relevance:

It is unclear which runners are at risk for developing clinically important metabolic derangements. Participating in prolonged endurance exercise appears to be safe in the majority of racers.

Cardiac troponins in young marathon runners

Cardiac troponin increases are common in adult marathon finishers. However, data on troponin values for young marathon runners are scarce. Forty young runners (20 healthy male and 20 female) 13 to 17 years old participated in this study. Blood samples were taken before, immediately after, and 24 hours after the race for determination of cardiac troponin T (cTnT) and troponin I (cTnI). Thirty-seven runners completed the race with a mean finishing time of 4 hours 53 minutes. No participant developed an adverse medical event during or after the race. In 30 of 37 participants, levels of cTnT and/or cTnI exceeded upper reference limits of 0.01 and 0.1 ng/ml immediately after the race, and in 3 participants these levels were even higher than the reference range for acute myocardial infarction (>0.1 and >0.5 ng/ml for cTnT and cTnI, respectively). Twenty-four hours after the race no participant had troponin levels exceeding the upper reference limits. Average increases of troponin levels did not differ between sexes. In conclusion, this is the first study to show that cardiac troponin levels increase to a similar extent in male and female adolescent marathon runners as observed in adults. Rapid recovery of troponin levels after a race is indicative of a physiologic rather than a pathologic response.

Resposta da frequência cardíaca e da concentração de lactato após cada segmento do triathlon olímpico

INTRODUÇÃO: As respostas fisiológicas de cada uma das modalidades envolvidas no triathlon são diferentes. Cargas de treino poderiam ser melhores prescritas se consideradas as individualidades fisiológicas de cada segmento para cada atleta. OBJETIVO: Observar o comportamento das variáveis fisiológicas, frequência cardíaca (FC) e concentração de lactato sanguíneo, antes e depois de cada segmento do triathlon: natação, ciclismo e corrida. MÉTODOS: Doze atletas do sexo masculino cumpriram uma prova de triathlon com distância olímpica. Coletas de sangue da polpa digital foram feitas antes do início da prova, após a natação, após o ciclismo, após a corrida e, ainda, uma hora após a prova. Cada atleta foi monitorizado com frequencímetro (Polar® S610) durante toda a prova. Análises estatísticas foram realizadas através da correlação de Spearman e teste de Wilcoxon para amostras não paramétricas (p<0,05). RESULTADOS: Nesta pesquisa, a maior intensidade foi registrada, em ambos os parâmetros fisiológicos, durante o ciclismo (86,3% da frequencia cardíaca máxima (FCmáx); 6,98mmol), seguida pela natação (85,2% FCmáx; 5,75mmol) e corrida (83,6% FCmáx; 4,47mmol), respectivamente. CONCLUSÃO: Conclui-se que a prescrição da carga de treino para o triathlon será mais eficiente se baseada nas respostas fisiológicas (FC e o lactato sanguíneo) individuais de cada modalidade.

Metabolic markers in sports medicine

Physical exercise induces adaptations in metabolism considered beneficial for health. Athletic performance is linked to adaptations, training, and correct nutrition in individuals with genetic traits that can facilitate such adaptations. Intense and continuous exercise, training, and competitions, however, can induce changes in the serum concentrations of numerous laboratory parameters. When these modifications, especially elevated laboratory levels, result outside the reference range, further examinations are ordered or participation in training and competition is discontinued or sports practice loses its appeal. In order to correctly interpret commonly used laboratory data, laboratory professionals and sport physicians need to know the behavior of laboratory parameters during and after practice and competition. We reviewed the literature on liver, kidney, muscle, heart, energy, and bone parameters in athletes with a view to increase the knowledge about clinical chemistry applied to sport and to stimulate studies in this field. In liver metabolism, the interpretation of serum aminotransferases concentration in athletes should consider the release of aspartate aminotransferase (AST) from muscle and of alanine aminotransferase (ALT) mainly from the liver, when bilirubin can be elevated because of continuous hemolysis, which is typical of exercise. Muscle metabolism parameters such as creatine kinase (CK) are typically increased after exercise. This parameter can be used to interpret the physiological release of CK from muscle, its altered release due to rhabdomyolysis, or incomplete recovery due to overreaching or trauma. Cardiac markers are released during exercise, and especially endurance training. Increases in these markers should not simply be interpreted as a signal of cardiac damage or wall stress but rather as a sign of regulation of myocardial adaptation. Renal function can be followed in athletes by measuring serum creatinine concentration, but it should be interpreted considering the athlete's body-mass index (BMI) and phase of the competitive season; use of cystatin C could be a reliable alternative to creatinine. Exercise and training induce adaptations in glucose metabolism which improve glucose utilization in athletes and are beneficial for reducing insulin insensitivity in nonathletes. Glucose metabolism differs slightly for different sports disciplines, as revealed in laboratory levels. Sport activities induce a blood lipid profile superior to that of sedentary subjects. There are few reports for a definitive conclusion, however. The differences between athletes and sedentary subjects are mainly due to high-density lipoprotein cholesterol (HDLC) concentrations in physically active individuals, although some differences among sport disciplines exist. The effect of sports on serum and urinary markers for bone metabolism is not univocal; further studies are needed to establish the real and effective influence of sport on bone turnover and especially to establish its beneficial effect.

Do male 100-km ultra-marathoners overdrink?

PURPOSE

Fluid overload is considered a main risk factor for exercise-associated hyponatremia (EAH). The aim of this study was to investigate the incidence of EAH in ultra-runners at the 100 km ultra-run in Biel, Switzerland.

METHODS

Pre- and postrace, body mass, urinary specific gravity, hemoglobin, hematocrit, plasma [Na+], and plasma volume were determined.

RESULTS

Of the 145 finishers, seven runners (4.8%) developed asymptomatic EAH. While running, the athletes consumed a total of (median and interquartile ranges) 6.9 (5.1-8.8) L over the 100 km distance, equal to 0.58 (0.41-0.79) L/h. Fluid intake correlated negatively and significantly with race time (r = -.50, P < .0001). Body mass decreased, plasma [Na+] remained unchanged, hematocrit and hemoglobin decreased, and urinary specific gravity increased. Plasma volume increased by 4.6 (-2.3 to 12.8) %. Change in body mass correlated with both postrace plasma [Na+] and Δ plasma [Na+]. Postrace plasma [Na+] correlated to Δ plasma [Na+]. Fluid intake was associated neither with postrace plasma [Na+] nor with Δ plasma [Na+]. Fluid intake was related to Δ body mass (r = .21, P = .012), but not to postrace body mass. Fluid intake showed no correlation to Δ plasma volume. Change in plasma volume was associated with postrace [Na+].

CONCLUSIONS

Incidences of EAH in 100 km ultra-marathoners were lower compared with reports on marathoners. Body mass decreased, plasma volume increased, and plasma [Na+] was maintained. Since fluid intake was related neither to Δ plasma volume nor to Δ plasma [Na+], we assume that factors other than fluid intake maintained body fluid homeostasis.

Prevalence of exercise-associated hyponatremia in male ultraendurance athletes

OBJECTIVE

The prevalence of exercise-associated hyponatremia (EAH) has mainly been investigated in marathoners and Ironman triathletes. The aim of this study was to investigate the prevalence of EAH in male ultraendurance athletes in other disciplines, such as ultraswimming, ultracycling, and ultramarathon running.

DESIGN

Observational field study.

SETTING

"Marathon Swim" in Lake Zurich, the "Swiss Cycling Marathon," the "Swiss Bike Masters," the "100-km Lauf Biel," and the "Swiss Jura Marathon."

PARTICIPANTS

Fifteen ultraswimmers, 28 ultra-road cyclists, 37 ultra-mountain bikers, 95 ultramarathoners, and 25 mountain ultramarathoners.

MAIN OUTCOME MEASURES

Changes in body mass, plasma sodium, urinary specific gravity, and hematocrit were measured. The athletes recorded their intake of fluids.

RESULTS

Two swimmers (13%), 3 road cyclists (10.7%), no mountain bikers (0%), 5 ultramarathoners (5%), and 2 mountain ultramarathoners (8%) developed EAH. In the mountain bikers (r = -0.41) and the 100-km ultramarathoners (r = -0.52), fluid intake was significantly and negatively related to race time. In the mountain ultramarathoners, fluid consumption increased during the race.

CONCLUSIONS

The prevalence of EAH was no higher in ultraendurance athletes compared with existing reports on marathoners and Ironman triathletes. Of the 200 investigated ultraendurance athletes, 12 finishers (6%) developed EAH.

No exercise-associated hyponatremia found in an observational field study of male ultra-marathoners participating in a 24-hour ultra-run

In a recent study of male ultra-marathoners who participated in a 161-km ultra-run, the prevalence of exercise-associated hyponatremia (EAH) was reported to be 50%, which is a considerably higher percentage than that seen in marathoners. We investigated the prevalence of EAH in male ultra-marathoners competing in a 24-hour run held in Basel, Switzerland. Body weight, hematocrit levels, plasma volume, plasma sodium concentration, urine specific gravity, and fluid intake were recorded in 15 male ultra-marathoners (mean age ± standard deviation [SD], 46.7 [5.8] years; plasma sodium, 71.1 [6.8] kg; height, 1.76 [0.07] m; body weight, 23.1 [1.84] kg/m(2)). Plasma sodium was measured at 135.3 (2.8) mmol/L before the race and remained unchanged at 135.4 (3.6) mmol/L after the race. The competitors consumed a total of 15.1 (5.1) L during the race, equal to 0.62 (0.21) L/hour. Fluid intake correlated to the mean running speed (r = -0.87; P = 0.0001). Body weight decreased significantly (P = 0.0009) by 2.2 kg. Hematocrit remained unchanged, and urine specific gravity increased significantly (P = 0.0005). Plasma volume increased by 4.9% (15.8%). Changes in body weight showed no association with post-race plasma sodium. The normal resting value should be 140 mmol/L so that a decrease of 5 mmol/L is described as EAH. Because the starting plasma sodium in this study was 135 mmol/L, it is not possible to define EAH as a value that is < 135 mmol/L. Instead, the correct definition should be a plasma sodium concentration of 130 mmol/L (ie, 5 mmol/L below the normal resting value). Following this definition, it was determined that no athlete developed EAH in this 24-hour run.

Low prevalence of exercise-associated hyponatremia in male 100 km ultra-marathon runners in Switzerland

We investigated the prevalence of exercise-associated hyponatremia (EAH) in 145 male ultra-marathoners at the '100-km ultra-run' in Biel, Switzerland. Changes in body mass, urinary specific gravity, haemoglobin, haematocrit, plasma [Na(+)], and plasma volume were determined. Seven runners (4.8%) developed asymptomatic EAH. Body mass, haematocrit and haemoglobin decreased, plasma [Na(+)] remained unchanged and plasma volume increased. Δ body mass correlated with both post race plasma [Na(+)] and Δ plasma [Na(+)]. Δ plasma volume was associated with post race plasma [Na(+)]. The athletes consumed 0.65 (0.30) L/h; fluid intake correlated significantly and negatively (r = -0.50, p < 0.0001) to race time. Fluid intake was neither associated with post race plasma [Na(+)] nor with Δ plasma [Na(+)], but was related to Δ body mass. To conclude, the prevalence of EAH was low at ~5% in these male 100 km ultra-marathoners. EAH was asymptomatic and would not have been detected without the measurement of plasma [Na(+)].

A study of serum sodium level among Hong Kong runners

OBJECTIVE

Hyponatremia and the associated life-threatening complications have emerged as an important issue among marathon runners. This study was conducted to estimate the serum sodium level among local marathon runners and to identify the associated risk factors of dysnatremia.

DESIGN

Prospective observational cohort study.

SETTING

Hong Kong Marathon 2008.

PARTICIPANTS

Subjects were approached at their convenience to participate in the study. Only full-marathon runners were recruited. They were to have had an unremarkable medical and drug history.

INTERVENTIONS

Demographic data, training information, previous marathon experience, anticipated drinking strategy, details of fluid consumption throughout the race, weight change, finishing time, and physical complaint.

MAIN OUTCOME MEASURES

Post-race serum sodium level.

RESULTS

Of the 6488 entries to the race, 370 runners (5.7%) were recruited. Among them, 272 (73.5%) completed the race and attended for blood sampling and data collection. One runner (0.4%) had hyponatremia (133 mmol/L) and 35 runners (12.9%) had hypernatremia (>145 mmol/L), whereas 236 runners (86.7%) had normal serum sodium (135-145 mmol/L) after the race. No symptomatic dysnatremia was found. A mean weight reduction of 0.70 kg was found after the race. An average of 1.9 L of fluid was consumed during the race and 2.5 L if the fluid consumed immediately before and after the race was also included. Hypernatremia was seen in runners who were better trained before the race, those who performed better, and those who drank less water after the race.

CONCLUSIONS

This is the largest prospective observational cohort study of dysnatremia conducted on athletes completing a standard marathon in Asia. No case of symptomatic dysnatremia was found.

Calcium supplementation and 4-week exercise on blood parameters of athletes at rest and exhaustion

In the present study, experiments were designed to investigate if supplementation with calcium during 4 weeks had an effect on blood parameters in sedentary male athletes at rest and exhaustion. Thirty healthy subjects of ages ranging from 18 to 22 years were included in the study. The subjects were separated into three groups, as follows: Group 1 consisted sedentary athletes receiving 35 mg/kg/day calcium gluconate. Group 2 included subjects equally supplemented with calcium training 90 min/day for 5 days/week. Group 3 were subject to the same exercise regime but did not receive calcium supplements. Blood parameters were determined in the experimental subjects at rest and after exhaustion. The leukocyte count (WBC) of athletes in groups 2 and 3 were significantly higher at exhaustion (p < 0.05). There were no significant differences in the WBC of the two supplemented groups. The erythrocyte count (RBC) was increased in the supplemented athletes after training (p < 0.05), but hemoglobin, hematocrit, and thrombocyte levels remained unchanged. The mean corpuscular volume increased in the calcium-supplemented group at rest (p < 0.05). These results suggest that calcium supplementation only causes increases in white and red blood cell counts in athletes after exhaustion while other hematological parameters remain unchanged.

Exercise-associated hyponatremia during winter sports

Exercise-associated hyponatremia (EAH) is hyponatremia that occurs <or= 24 hours after prolonged physical activity. It is a potentially serious complication of marathons, triathlons, and ultradistance events, and can occur in hot and cold environments. Clear evidence indicates that EAH is a dilutional hyponatremia caused by excessive fluid consumption and the inappropriate release of arginine vasopressin. Cerebral and pulmonary edema can cause serious signs and symptoms, including altered mental status, respiratory distress, seizures, coma, and death. Rapid diagnosis and urgent treatment with hypertonic saline is necessary to prevent severe complications or death. Prevention is based on educating athletes to avoid excessive drinking before, during, and after exercise.