Fatal water intoxication and cardiac arrest in runners during marathons: prevention and treatment based on validated clinical paradigms

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.

[Medical emergencies during running events]

Hintergrund

Die Anzahl an kurz- und langstreckigen Laufveranstaltungen in Deutschland nimmt zu. Laufen als Breitensport wird von einer Vielzahl an Personen unterschiedlicher Altersklassen, Risikogruppen und Professionalisierungsgrade betrieben, woraus ein breites Spektrum medizinischer Notfälle resultiert.

Ziel der Arbeit

Der vorliegende Beitrag erläutert die Inzidenz, Pathophysiologie und Therapie relevanter Notfallbilder bei Laufveranstaltungen. Ziel ist die Optimierung der Arbeitsabläufe des Rettungsdienstpersonals.

Material und Methoden

Es erfolgte eine Literaturrecherche in PubMed.

Ergebnisse

Anstrengungsassoziierte Muskelkrämpfe, gastrointestinale Symptome, Kollaps, Kompartmentsyndrom und Tendinopathien sind häufige Erscheinungsbilder und resultieren meist aus akuter oder chronischer Überanstrengung. Der Kreislaufstillstand bzw. plötzliche Herztod ist ein seltenes Ereignis bei Laufveranstaltungen. Bewusstseinsstörungen und generalisierte Krampfanfälle sind schwerwiegende Komplikationen. Disseminierte intravasale Koagulopathie, belastungsinduzierte Hyponatriämie, Hitzschlag, Rhabdomyolyse und thromboembolische Ereignisse sind mit hoher Morbidität und Mortalität verbunden. Substanzen zur Erhöhung der Schmerzschwelle und leistungssteigernde Substanzen sind unter Läufern stark verbreitet und gehen mit einer hohen Rate an Nebenwirkungen einher.

Diskussion

Unspezifische Symptome wie Erbrechen, Fieber, Kollaps, Muskelschmerzen, Übelkeit, und Schwäche sind die führenden Symptome bei Laufveranstaltungen. Eine sorgfältige Anamnese ist wegweisend für eine zielgerichtete klinische Therapie. Präklinisch steht eine Symptomkontrolle im Mittelpunkt. Das Flüssigkeitsmanagement stellt eine besondere Herausforderung dar.

Life threatening water intoxication

Water intoxication is a fatal disorder associated with disturbance in brain function, known as hypo-osmolar syndrome which resulting from an excessive water intake, with dilutional hypernatremia leads to a potentially fatal outcome. A change in the electrolyte equilibrium such as this sudden drop in serum sodium level and then subsequent mortality. With hyponatremia, the plasma osmolality decreased leading to water movement into the brain according to the osmotic gradient, resulting in hyponatremic encephalopathy and cerebral oedema. Increased water intake such as in Psychogenic polydipsia is followed by urination of high amount of diluted urine (polyuria) which are the main initial symptoms of water intoxication with headache, blurred vision, nausea, tremor, and deterioration in psychosis. Other serious symptoms involve muscle spasms, Early detection of seizures and coma are more serious outcomes, Untreated cases may lead to death, Risk factor for water intoxication are Marathon runners, military population and athletes and due to this endurance events, these behaviors encouraging heavy sweating that result in heat exhaustion and consume large volumes of fluid, then hyponatremia developed as a result of excessive fluid substitution. Child abuse is other pediatric clinical cases reported with water intoxication. Psychogenic polydipsia which is psychiatric disorder with obsessive water drinking leading to a serious self-induced water intoxication (SIWI), water is normally metabolized and excreted by different means and it is mainly by kidneys in urine, evaporation through the skin, by respiratory system through the respired water vapor and little quantity of water was lost from the gastrointestinal tract (GI).The LD50 of water is > 90 ml/kg orally in rats. The current review illustrates the Life threatening effects of water when it is aggressively consumed.

Elite 100-km road ultramarathon runners: characteristics and musculoskeletal injuries

BACKGROUND

Currently known data about ultramarathon medical issues has been collected from all combinations of ultramarathon race types (road, trail, etc.) and the population in those studies consists of mixed elite and recreational athletes. There are few studies concerning injuries related to musculoskeletal system injuries in ultramarathon runners.

METHODS

The study was conducted on total of 77 elite ultramarathoners based on a questionnaire-based survey. We studied the elite male and female athletes who participated in the 30^th IAU 100-km World Championships held in Croatia, in 2018.

RESULTS

Ultramarathon runners have higher percentage of lower-leg injuries and rehabilitation of those injuries tend to last longer as ultramarathon runners show specific training habits with less days off and hold a permanent, full-time job and often with a higher academic degree. Furthermore, also the mean age is higher.

CONCLUSIONS

Ultramarathoners have a higher percentage of lower-leg injuries than runners who do not run distances beyond a marathon. In addition, rehabilitation tends to last longer. This may well be correlated also to their specific training loads with fewer days off and training whilst holding a permanent full-time job. Often, they also hold a higher academic degree with years spent in the education system which might influence their mindsets on the medical issues they encounter. Also, being older may also have a bearing on injury occurrence and rehabilitation time.

Effects of the Amount and Frequency of Fluid Intake on Cognitive Performance and Mood among Young Adults in Baoding, Hebei, China: A Randomized Controlled Trial

Water is a critical nutrient that is important for the maintenance of the physiological function of the human body. This article aimed to investigate the effects of the amount and frequency of fluid intake on cognitive performance and mood. A double-blinded randomized controlled trial was designed and implemented on college students aged 18–23 years in Baoding, China. Participants were randomly assigned into one of three groups: the recommended behavior group (RB group) who drank 200 mL of water every 2 h, the half amount group (HA group) who drank 100 mL of water every 2 h, and the high frequency group (HF group) who drank 110 mL of water every 1 h. The intervention lasted 2 days. Urine osmolality, cognitive performance, and mood of participants in each group were compared using the one-way analysis of variance (ANOVA). A total of 92 participants (46 females, 46 males) completed this study with a completion rate of 95.8%. The urine osmolality of the HA group was higher than that of the RB group and the HF group at two time points (p < 0.05). At time point 1, the scores in the portrait memory test and vigor were statistically different (F = 20.45, p < 0.001; F = 5.46, p = 0.006). It was found that the scores for the portrait memory test in the RB group were lower than those in the HA group and the HF group (p = 0.007; p < 0.001), while the scores of the HF group were higher than those of the HA group (p < 0.001). The scores for vigor in the RB group were significantly higher than those of the HA group (p = 0.006), and they were also significantly higher than those of the HF group (p = 0.004). At time point 2, only the scores for vigor were statistically different (F = 3.80, p = 0.026). It was found that the scores for vigor in the RB group were higher than those in the HA group and HF group (p = 0.018; p = 0.019). Both the amount and frequency of fluid intake may affect urine osmolality and vigor, but these factors have limited impacts on cognitive performance. Rational fluid intake behavior may be beneficial to improve the hydration status and mood of young adults. More research is needed, especially experimental research, to allow causal conclusions to be drawn.

International Society of Sports Nutrition Position Stand: nutritional considerations for single-stage ultra-marathon training and racing

Background

In this Position Statement, the International Society of Sports Nutrition (ISSN) provides an objective and critical review of the literature pertinent to nutritional considerations for training and racing in single-stage ultra-marathon. Recommendations for Training. i) Ultra-marathon runners should aim to meet the caloric demands of training by following an individualized and periodized strategy, comprising a varied, food-first approach; ii) Athletes should plan and implement their nutrition strategy with sufficient time to permit adaptations that enhance fat oxidative capacity; iii) The evidence overwhelmingly supports the inclusion of a moderate-to-high carbohydrate diet (i.e., ~ 60% of energy intake, 5–8 g·kg^− 1·d^− 1) to mitigate the negative effects of chronic, training-induced glycogen depletion; iv) Limiting carbohydrate intake before selected low-intensity sessions, and/or moderating daily carbohydrate intake, may enhance mitochondrial function and fat oxidative capacity. Nevertheless, this approach may compromise performance during high-intensity efforts; v) Protein intakes of ~ 1.6 g·kg^− 1·d^− 1 are necessary to maintain lean mass and support recovery from training, but amounts up to 2.5 g.kg^− 1·d^− 1 may be warranted during demanding training when calorie requirements are greater; Recommendations for Racing. vi) To attenuate caloric deficits, runners should aim to consume 150–400 Kcal·h^− 1 (carbohydrate, 30–50 g·h^− 1; protein, 5–10 g·h^− 1) from a variety of calorie-dense foods. Consideration must be given to food palatability, individual tolerance, and the increased preference for savory foods in longer races; vii) Fluid volumes of 450–750 mL·h^− 1 (~ 150–250 mL every 20 min) are recommended during racing. To minimize the likelihood of hyponatraemia, electrolytes (mainly sodium) may be needed in concentrations greater than that provided by most commercial products (i.e., > 575 mg·L^− 1 sodium). Fluid and electrolyte requirements will be elevated when running in hot and/or humid conditions; viii) Evidence supports progressive gut-training and/or low-FODMAP diets (fermentable oligosaccharide, disaccharide, monosaccharide and polyol) to alleviate symptoms of gastrointestinal distress during racing; ix) The evidence in support of ketogenic diets and/or ketone esters to improve ultra-marathon performance is lacking, with further research warranted; x) Evidence supports the strategic use of caffeine to sustain performance in the latter stages of racing, particularly when sleep deprivation may compromise athlete safety.

[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.

Mortality during marathons: a narrative review of the literature

Background

Millions of community-dwelling individuals run marathons each year. There are infrequent deaths, which are often reported widely, and may create unnecessary alarm about the potential risks. Equally, sensible planning for such eventualities is important when staging an event.

Objective

The aim of the review was to determine the risk of death from running a marathon and the likely location of such deaths in order to inform the public of the likely risks and improve planning for such events.

Design

Narrative review.

Data sources

Primary: PubMed. Secondary: contact was made with the organisers and medical teams of specific marathons and online data sought where necessary.

Eligibility criteria for selecting studies

Studies had to report the number of participants and deaths during, or within 24 hours of completing the marathon. Results relevant to half marathons or ultramarathons or other endurance events, such as triathlons, were not included. Deaths due to terrorist activity were not included.

Results

The risk of death estimated by these studies was approximately 0.67 per 100 000 finishers, that is, 1 death per 149 968 participants. From those studies that reported deaths by sex, the rate of male deaths was 0.98/100 000 (1 per 102 503) vs 0.41/100 000 (1 per 243 879) in females. Deaths tended to occur in the last quarter of the race.

Summary/conclusion

The risk of death from participating in a marathon is small. Men are more at risk than women. Deaths tend to occur later in the race.

Aspirin to Prevent Sudden Cardiac Death in Athletes with High Coronary Artery Calcium Scores

While proficient cardiac resuscitation has improved survival following cardiac arrest during road races in Japan, this accomplishment does not address coronary artery disease as the underlying cause of an increasing frequency of cardiac arrest in middle-aged men during marathons and ironman triathlons in the United States since the year 2000. Based on the high prevalence of subclinical coronary artery disease by cardiac computed tomography in endurance athletes with low conventional cardiac risk-factor profiles, we recommend coronary artery calcium scores as a more reliable and independent predictor of incident cardiac events, including death, as validated among adults aged 30-46 years. Scores of over 100 Agatston units indicate a 10-year cardiac risk of 7.5%, at which additional measures for primary prevention are recommended, including aspirin, as shown conclusively to reduce first myocardial infarctions in same-aged men in a prospective double-blind controlled trial. Targeted screening for subclinical coronary atherosclerosis with coronary artery calcium scores is prudent to guide appropriately dosed aspirin use to mitigate the increasing frequency of sports-related sudden cardiac death due to plaque rupture.

Low serum sodium levels at hospital admission: Outcomes among 2.3 million hospitalized patients

Background

Hyponatremia is the most common electrolyte disorder among hospitalized patients. Controversies still exist over the relationship between hyponatremia and outcomes of hospitalized patients.

Methods

To analyze the association of low serum sodium levels at hospital admission with in-hospital mortality and patient disposition and to compare the distribution of the risk of death associated with hyponatremia across the lifespan of hospitalized patients, we conducted an observational study of 2.3 million patients using data extracted from the Cerner Health Facts database between 2000 and 2014. Logistic regression models were used in the analyses.

Results

At hospital admission 14.4% of hospitalized patients had serum sodium levels [Na] <135 mEq/L. In adjusted multinomial logistic regression analysis, we found that the risk of in-hospital mortality significantly increases for [Na] levels < 135 or ≥143 to ≤145 mEq/L compared to the reference interval of 140 to <143 mEq/L (p<0.001). We observed similar trends for the relationship between [Na] levels and discharge to hospice or to a nursing facility. We demonstrated that younger age groups (18 to <45, 45 to <65) had a higher risk of in-hospital mortality compared to older age groups (65 to <75, ≥75) for [Na] levels <130 mEq/L or 143 to ≤145 mEq/L (p<0.001).

Conclusions

Hyponatremia is common among hospitalized patients and is significantly associated with in-hospital mortality, discharge to hospice or to a nursing facility. The risk of death and other outcomes was more evident for [Na] <135 mEq/L. The mortality associated with low [Na] was significantly higher in younger versus older patients.

Prerace aspirin to protect susceptible runners from cardiac arrest during marathons: is opportunity knocking?

While endurance exercise such as marathon training is cardioprotective, an increasing frequency of race-related cardiac arrests and sudden death has been observed in middle-aged men since the year 2000. An evidence-based strategy for prevention is considered based on identifying atherothrombosis as the underlying cause in this susceptible subgroup. Review of all articles on PubMed related to acute cardiac events during marathons. Male gender and the marathon compared with the half-marathon were identified as significant risk factors for race-related cardiac arrests, which events increased 2.3-fold in the latter half of a 10-year prospective registry beginning in the year 2000. There were 50 cardiac arrests in runners who were 86% male with a mean age of 42 years. The main cause of sudden death was atherosclerotic heart disease in those over the age of 40 including myocardial infarction in 12 of 13 (93%) cases over the age of 45 as assessed retrospectively. Inflammatory biomarkers predicting acute cardiac events and hypercoagulability with in vivo platelet activation were demonstrated in same-aged asymptomatic middle-aged men during marathons. Excess cardiac morbidity and mortality in middle-aged men during marathons is mediated by atherothrombosis which may render non-obstructive coronary atherosclerotic plaques vulnerable to rupture. Prerace low-dose aspirin usage is prudent to protect susceptible runners from a high, if transient, risk for cardiac arrest during races as evidence-based to prevent first myocardial infarctions in same-aged healthy men.