IntroductionThe Comrades Marathon is the world’s oldest and largest ultra-marathon, held annually between Durban and Pietermaritzburg, South Africa, since 1921. As a nationally televised event with substantial participation, it provides a unique natural laboratory for studying the physiological demands of prolonged, high-intensity endurance running. This narrative review synthesizes current evidence on physiological responses, performance trends, and health implications associated with participation in the Comrades Marathon.MethodsA systematic search of EBSCO, PubMed, SciELO, and Web of Science identified studies published up to December 2025. Of 116 records retrieved, 42 publications (field studies and case reports) met eligibility criteria and focused specifically on the Comrades Marathon.ResultsWomen represented 4.2% of finishers, with female participation beginning in 1975. Growth in finishers during the 1970s was driven primarily by men aged 30–59 years. Men were consistently faster than women across all age groups, although the sex performance gap narrowed over time and overall performance improved. Peak performance occurred at ∼29.9 years in men and ∼36.0 years in women. Medical encounters occurred at rates up to 20 per 1000 starters. The most affected organ systems were fluid/electrolyte (8.8%; 8.3–9.4), central nervous system (4.0%; 3.7–4.5), and gastrointestinal (2.9%; 2.6–3.2). Dehydration (7.5%; 7.0–8.1) and exercise-associated muscle cramping (3.2%; 2.9–3.6) were the most common diagnoses. Exercise-associated hyponatremia was uncommon (<2%), whereas hypernatremia was substantially more prevalent. Early race editions reported isolated deaths, likely due to ischemic heart disease. Cardiac biomarker elevations and echocardiographic changes observed post-race were transient. The race induced muscle inflammation without major knee MRI abnormalities. In the 1970s, cases of acute kidney injury and renal failure occasionally required dialysis. Faster, well-trained runners showed higher rates of post-race upper respiratory tract infection than slower, less-trained runners.ConclusionsParticipation in the Comrades Marathon is associated with well-characterized post-race physiological disturbances. Notably, the event demonstrates an unusually high prevalence of acute kidney injury and hypernatremia compared with other ultra-endurance races, underscoring the substantial renal and fluid–electrolyte stress imposed by prolonged, high-intensity running in challenging environmental conditions. These insights can inform individualized hydration strategies, targeted race preparation, and optimized medical support for ultra-endurance athletes.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/view/CRD420251252644, identifier CRD420251252644.

It is well known that the fastest elite marathon runners come from East African countries such as Ethiopia and Kenya. However, to date, there is no information available on the origin of the fastest age group (master) marathoners. This study aimed to determine the countries of origin of the fastest age group marathoners who have participated in the 'New York City Marathon' over the past several decades. Race data from 1,009,839 runners (626,183 male and 383,656 female finishers) who completed the 'New York City Marathon' between 1999 and 2024 were analyzed. Participants were categorized into five-year age groups: <20, 20-24, 25-29, 30-34, 35-39, 40-44, 45-49, 50-54, 55-59, 60-64, 65-69, 70-74, and 75 + years. The data were stratified by sex (male and female) and country of origin. The dataset was organized into five performance-based subgroups: (i) the entire dataset, including all finishers by age group and nationality; (ii) the top 100 finishers per age group; (iii) the top 30 finishers per age group; (iv) the top 10 finishers per age group; and (v) the top individual from each country within each age group. Regression analyses were conducted to explore demographic predictors of marathon performance. Participation generally increased over the study period, with temporary declines during the COVID-19 pandemic; male participation consistently outnumbered female participation, the 40-44 years age group was the most represented for both sexes, and participation was lowest in the youngest (< 20 years) and oldest (75 + years) age groups. Crucially, analyses focusing on the fastest age-group marathoners revealed clear nationality-based performance patterns. In younger adult age groups (20-39 years), the fastest average race times were predominantly achieved by female and male runners from Kenya and Ethiopia. The < 20 years age category showed comparatively stronger performances from European runners, including those from Poland, Switzerland and Italy. In the 50 years and older age groups, the best average times were increasingly recorded by runners from the United States of America, Japan, Germany and Switzerland. This shift highlights a regional transition in peak marathon performance with increasing age, from East African to European, North American, and East Asian dominance.

While the dominance of elite East African marathoners is well-established, little is known about the nationality distribution of the fastest age group marathoners. This study examined how the nationality distribution of the fastest marathon runners varies across age groups and sexes in the 'Berlin Marathon'. We analysed race data from 825,886 finishers (627,962 men and 197,807 women) of the 'Berlin Marathon' from 1999 to 2024. Finishers were grouped by five-year age brackets, sex and nationality. We examined performance across five analytical layers: (1) all runners, (2) top 100, (3) top 30, (4) top 10 and (5) the single fastest runner per country and age group. Linear regression models were applied to both the entire dataset and the subset of the top 100 finishers per age group to assess the predictive value of age and nationality on finish time. Most finishers were from Germany, with the USA becoming the second-most represented country after 2017. In younger age groups (20-39 years), the fastest average times for both sexes were achieved by runners from Kenya and Ethiopia. In middle-aged (40-49 years) and older groups (50 + years), top performances shifted toward runners from Germany, the United States, Japan, and Switzerland. In regression models, age group and nationality explained only 4.1% of the variance in male finish times and 2.9% in females across the full dataset. However, for the top 100 runners, explanatory power rose significantly to 52.8% for men and 48.6% for women. The nationality distribution of the fastest age group marathoners shifts with age in the 'Berlin Marathon': East African nations dominate at younger ages, while Western Europe and East Asian countries lead among older runners. These results emphasize the global expansion of competitive master running and the role of cultural and demographic factors in shaping endurance performance across the lifespan.

BACKGROUND:IRONMAN® 70.3 events represent a rapidly expanding endurance discipline characterized by distinct physiological demands, performance determinants, and race-specific risk profiles. Despite their global popularity, no systematic review has synthesized evidence exclusively focused on this distance. OBJECTIVE:To consolidate current knowledge on performance predictors, physiological responses, training characteristics, nutritional strategies, environmental influences, and medical considerations in IRONMAN® 70.3 triathletes, and to identify gaps requiring further investigation. METHODS:A systematic search of PubMed, Scopus, SciELO, EBSCO and Google Scholar was conducted up to 25th November 2025. Search terms were developed according to PRISMA guidelines and included variations of 'Ironman 70.3', 'half triathlon' and 'middle-distance triathlon'. Eligible studies reporting physiological, anthropometric, nutritional, environmental, medical, or performance-related outcomes specific to IRONMAN® 70.3. Risk of bias was assessed using the Newcastle-Ottawa Scale, the Cochrane RoB tool, and the NIH Quality Assessment Tool, according to study design. RESULTS:A total of 86 studies were included, predominantly observational in design, with sample sizes ranging from 1 to 852,721 participants, mostly trained male triathletes aged 25-39 years. Participation has increased across age groups, with pronounced growth among female and masters triathletes. Peak performance in professional male triathletes is reached at approximately age 28, and in female triathletes at age 32. Across large datasets, cycling appeared to be the strongest predictor of overall race time, accounting for the largest proportion of performance variance. Physiologically, competition was associated with transient reductions in immune function, reversible muscle damage, and shifts in hydration and electrolyte balance, while higher intracellular water and efficient fat oxidation were associated with better outcomes. CONCLUSIONS:Evidence specific to IRONMAN® 70.3 is limited by small sample sizes, heterogeneous designs, male-dominated cohorts, and insufficient sex-specific analyses. Future research should distinguish recreational from elite triathletes, incorporate balanced sex representation, and apply standardized physiological and environmental monitoring to refine targeted recommendations for performance, health, and safety.

Background The Spartathlon is a 246-km ultra-endurance running race, considered as one of the most iconic and physically demanding ultra-marathons in the world. In this narrative review, we aimed to synthesize the available current evidence on the physiological responses, performance trends, and health implications associated with participation in the Spartathlon. Methods A systematic literature search was conducted to identify high-quality scientific studies on the Spartathlon. The databases Cochrane, EMBASE, PubMed, Scopus, and Web of Science were used to retrieve articles published up to December 2025. We found a total of 33 publications in Web of Science, 25 in Embase, 24 in Scopus, 23 in PubMed, and 1 in Cochrane. After removing duplicates and applying the eligibility criteria, a final selection of studies was included for analysis in this narrative review. Results The findings on the cardiac system showed reversible changes in echocardiography and cardiac biomarkers. Running the Spartathlon leads to specific effects on the locomotor system, such as an increase in peak pressure in the forefoot area, an increase in biochemical markers of muscle damage and changes in bone metabolism markers. Notably, the use of oral proton pump inhibitors was associated with a lower incidence of gastrointestinal bleeding. The Spartathlon also showed the highest prevalence of exercise-associated hyponatremia (EAH) of up to 65% as reported in the literature on ultra-marathon running. In addition, running Spartathlon leads to an inflammatory response and an increase in oxidative stress. Conclusions Participation in the Spartathlon leads to several well-documented post-race physiological alterations, particularly affecting the cardiovascular and musculoskeletal systems. Overall, the Spartathlon represents a unique model for studying human physiological resilience and adaptation under extreme conditions.

The 24-hour ultra-marathon is a specific race format with a long tradition and high popularity. To date, no comprehensive review has systematically summarized the scientific literature on 24-hour ultra-marathon running. We performed a comprehensive search in the PubMed and Scopus databases, covering studies published until the end of 2025. The participation of runners and finishers in 24-hours has increased in the past decades. Most participants in 24-hours are age group or master runners older than 35 years. 24-hour ultra-runners typically cover distances exceeding 100 km per event, with an average distance ranging from 150–160 km, while the top performers can achieve over 200 km. Men achieve greater distances than women. The best performance is achieved at 40–50 years. The most important predictive variables in 24-hours are training, nutrition, previous experience, and pacing; anthropometric characteristics seemed of no predictive value. During 24-hours, athletes ingest mainly carbohydrates and experience an energy deficit, but rarely exercise-associated hyponatremia. A 24-hour run leads to decrease in body mass, which can be due to dehydration, a loss of skeletal muscle mass, and/or a loss of fat mass. A 24-hour run has effects on the cardiovascular system (i.e., decrease in blood pressure, changes in cardiac biomarkers, and changes in electrocardiogram and echocardiographic findings), the kidneys (i.e. reversible impairment of kidney function), the digestive system (i.e., gastrointestinal discomfort, reversible increase in liver enzymes), the immune system (i.e., increase in immune markers) and the hematological system (i.e., decrease in red blood cells, increase in white blood cells). All negative effects are resolved within 2–3 days. In summary, 24-hour ultra-marathon runners are master athletes with extensive experience, optimal training preparation, and optimal nutrition to complete a 24-hour run successfully. The adverse effects on the heart, kidneys, immune system, and digestive tract generally resolve within a few days after the event. Future studies need to investigate nutrition after the race to enhance recovery and the impact of training and competing in this specific race format on the locomotor system (i.e. skeleton, muscles, tendons, joints).

The 'New York City Marathon' is one of the world's largest and most influential mass-participation marathons. Although numerous studies have examined performance trends, participation patterns, pacing behavior, environmental influences, and physiological aspects of runners in this event, no review has synthesized the evidence specific to this race. This study aimed to systematically summarize the scientific literature on the 'New York City Marathon'. A systematic search of Scopus, PubMed, Web of Science, Embase, and Cochrane was conducted using terms related to the 'New York City Marathon' to identify studies published up to February 2026. Eligible studies included runners of all ages, sexes, and performance levels, with no restrictions on publication date, topic, or study design. Extracted data included: (1) authors; (2) publication year; (3) study design; (4) sample characteristics; (5) variables assessed; and (6) main findings. Results were synthesized narratively by domain. Seventy-six publications met the inclusion criteria. Participation increased markedly over time, driven primarily by growth among women and age-group runners. While elite and competitive age-group performances improved in recent decades, mean finish times across the entire field increased by ~40 min since the 1970s, reflecting the democratization of marathon running. Ethiopian runners were the youngest and fastest. Peak performance occurred at 29.7 years in women and 34.8 years in men (1-year age intervals), and in the 30-34 and 35-39 age groups, respectively (5-year intervals). Approximately 10 % of runners experienced major injuries during training or the race that prevented starting or finishing. Higher training volumes increased injury risk, with foot, knee, and hip injuries most common, whereas adequate preparation reduced risk. Environmental conditions-particularly temperature-had a stronger influence on race times than course metrics. Performance declined with increasing temperature, especially among slower runners and among men aged 30-64 and women aged 40-64. Runners generally adopted a positive pacing strategy with a final spurt in the last segment (40-42.2 km). The fastest split occurred between 5-10 km and the slowest between 35-40 km, coinciding with the undulating terrain entering Central Park. Older athletes paced more evenly than younger athletes. Men showed a larger decrease in running speed from the fastest to the slowest splits than women (21.1 % vs. 16.7 %). Slower runners exhibited greater early-race deceleration but larger late-race speed increases, whereas faster runners maintained the most even pacing. Participation in the 'New York City Marathon' has grown substantially, driven by increased involvement of women and age-group runners. Although elite performance has improved, overall mean finish times have slowed due to broader participation. Ethiopian runners were the youngest and fastest, with peak performance occurring in the early to mid-30s. Injury prevalence was considerable, particularly with higher training volumes, though adequate preparation mitigated risk. Higher temperatures slowed performance, especially among slower runners. Pacing was predominantly positive, with older athletes pacing more evenly and faster runners showing the smallest performance decline. Future research should explore cardiovascular monitoring technologies-including real-time ECG streaming during the race-and assess the impact of innovations such as carbon-plated "supershoes" on performance and pacing. See also the graphical abstract(Fig. 1).

The ‘Norseman Xtreme Triathlon’, held annually in Norway, is considered one of the world's most challenging triathlons, surpassing the traditional IRONMAN®-distance in terms of difficulty. This narrative review aims to summarize the current scientific evidence to support athletes and coaches in preparation for this event. We conducted a narrative review to summarize the current scientific literature on the ‘Norseman Xtreme Triathlon’. A structured search was conducted in two major databases—PubMed and Scopus—using free-text terms related to ‘Norseman Xtreme Triathlon’. The search included articles published up to the end of November 2025, without language restrictions. After removing duplicates and unrelated articles based on title and abstract screening, 16 relevant publications were included for analysis. Over the years, the number of female and male finishers increased, the men-to-women ratio decreased, and both split and overall race times decreased. Most athletes competing in the 'Norseman Xtreme Triathlon' came from Norway, and Norwegian athletes achieved the most podiums. The race affects different organ systems and biomarkers, with increased values of WBC, CK, NT-proBNP, CRP and AST returning to pre-race levels within hours or days. Due to the cold environment, athletes appeared to be at risk of developing hypothermia and swimming-induced pulmonary edema (SIPE) during swimming and both exercise-induced bronchoconstriction (EIB) and exercise-induced arterial hypoxemia (EIAH) after the race. Particular care is needed in preparing for the cold water and general cold environment during cycling and running. The specific nutritional demands, the aspects of pre-race preparation (e.g. training, experience), post-race recovery trajectories, hormonal profiles, or psychological responses of the ‘Norseman Xtreme Triathlon’ remain underexplored and represent an important area for future research.

Background and purpose Lifelong endurance exercise is generally associated with cardiovascular health benefits. However, recent studies suggest that prolonged high-volume training may contribute to coronary atherosclerosis, even in athletes with low traditional cardiovascular risk. This case report aims to explore the cardiovascular status of a master endurance athlete with an exceptionally high lifetime training volume, in light of recent concerns raised in the literature. Methods We present the case of a 60-year-old recreational male marathon runner with no history of cardiovascular disease, who completed over 500 marathons between the ages of 30 and 60 years, covering ∼127 ​000-km running. In 2024 alone, he completed 60 marathons. Cardiovascular evaluation included clinical risk assessment and coronary computed tomography angiography (CTCA). Results The runner was asymptomatic, had a low ESC-SCORE2 (3.3%), a favorable lipid profile, and normal levels of high-sensitivity C-reactive protein and lipoprotein (a). CTCA revealed no evidence of calcified, mixed, or non-calcified coronary plaques. Conclusions This case highlights that some master athletes may demonstrate resilience to coronary atherosclerosis despite decades of high training volume. In low-risk individuals, prolonged endurance training alone may not necessarily lead to coronary artery disease, emphasizing the need for individualized cardiovascular screening strategies.

The role of sodium supplements and sex in the occurrence of exercise-associated hyponatremia (EAH) remains controversial. This study investigated hydration status in ultrarunners (19 males and 9 females) who completed seven marathons over seven consecutive days. Due to the limited number of female participants, no statistical comparison between sexes was performed. Plasma sodium concentration ([Na+]) and multiple hydration markers were assessed before, during, and after the race. Reported sodium supplement consumption showed no association with plasma [Na+]. An overall decline in plasma [Na+] was observed in females (regression slope = -1.278, p = 0.02) across the event, whereas no significant change was detected in males (slope = -0.325, p = 0.57). Additionally, no significant associations were found between plasma [Na+] and other monitored variables, including sodium supplement intake, pre-race hydration strategy, body mass, total body water, plasma osmolality, hematocrit, hemoglobin, urine specific gravity, urinary [Na+], thirst rating, or fluid intake reported pre-, during, and post-stage. No cases of symptomatic or asymptomatic hyponatremia were identified, suggesting that total fluid and sodium intake were adequate to maintain fluid-electrolyte balance and prevent EAH in both sexes.

Background:Swimming-induced pulmonary oedema (SIPO) has predominantly been reported in swimmers. However, to date, no review has specifically explored the scientific literature concerning the occurrence and characteristics of SIPO in triathletes. Therefore, this review aims to summarize and discuss the current evidence on SIPO in the context of triathlon. Methods:We conducted a narrative review to summarize the current scientific literature on SIPO in triathletes. A structured search of two major databases-PubMed and Scopus-was conducted using free-text terms related to SIPO and triathlon. The search included articles published up to January 2025, with no language restrictions. After removing duplicates and excluding animal or in vitro studies, as well as unrelated articles based on title and abstract screening, a total of 48 relevant publications were included for analysis. Results:The reports on SIPO in triathletes are mainly case reports or case studies on a single athlete or a small number (case series) of triathletes. Most reported cases involved middle-aged women (30-60 years) participating in IRONMAN® 70.3 and IRONMAN® triathlons. The prevalence of SIPO in triathletes is reported to be less than 1.5%. Risk factors for SIPO in triathletes are female sex, age over 50 years, hypertension, fish oil consumption, highly trained individuals, competitive exercise, wet suit compression, longer race distances (i.e. IRONMAN® 70.3 or IRONMAN®) and a cold (water) environment. The symptoms and outcome are similar to those observed in swimmers and other aquatic athletes. Conclusions:In summary, the results regarding the prevalence, symptoms and risk factors of SIPO in triathletes are comparable to those in other aquatic athletes. SIPO occurs only in IRONMAN® 70.3 and IRONMAN® races, but has not been reported in the Olympic distance triathlon or triathlons longer than the IRONMAN® race distance.

Abstract Background Marathon training and running have many beneficial effects on human health and physical fitness; however, they also pose risks. To date, no comprehensive review regarding both the benefits and risks of marathon running on different organ systems has been published. Main Body The aim of this review was to provide a comprehensive review of the benefits and risks of marathon training and racing on different organ systems. A predefined search strategy including keywords (e.g., marathon, cardiovascular system, etc.) and free text search was used. Articles covering running regardless of sex, age, performance level, and event type (e.g., road races, mountain marathons) were considered, whereas articles examining only cycling, triathlon, stress-tests or other sports were excluded. In total, we found 1021 articles in PubMed, Scopus, and Google Scholar, of which 329 studies were included in this review. Overall, marathon training offers several benefits for different organ systems and reduces all-cause mortality. As such, it improves cardiovascular risk factors, leads to favorable cardiac adaptations, enhances lung function, and improves quality of life in chronic kidney disease patients. It also enhances gastrointestinal mobility and reduces the risk of specific tumors such as colorectal cancer and hepatocellular carcinoma. Marathon training enhances bone health and skeletal muscle metabolism. It further positively affects hematopoiesis and cytotoxic abilities of natural killer cells, and may act neuroprotective on a long-term basis. After a marathon, changes in biomarkers suggesting pathological events in certain organ systems such as cardiovascular, renal, gastrointestinal, liver, hematological, immune, musculoskeletal, central nervous, and endocrine systems can often be observed. Mostly, these changes are limited to 1–3 days post-race and usually normalize within a week. Moreover, marathon running poses the risk of serious adverse events such as sudden cardiac death or acute liver failure. Concerning lung function, a decrease after a marathon race was observed. Acute kidney injury, as well as electrolyte imbalances, are relatively common amongst marathon finishers. Many runners complain of gastrointestinal symptoms during or after long-distance running. Many runners suffer from running-related musculoskeletal injuries often impairing performance. A marathon is often accompanied by an acute inflammatory response with transient immunosuppression, making runners susceptible to infections. Also, hormonal alterations such as increased cortisol levels or decreased testosterone levels immediately after a race are observed. Disturbances in sleep patterns are commonly found in marathon runners leading up to or directly after the race. Conclusion All in all, marathon training is generally safe for human health and individual organ systems. Considering the high popularity of marathon running, these findings supply athletes, coaches, sports scientists, and sports medicine practitioners with practical applications. Further large-scale studies examining long-term effects on the cardiovascular, renal, and other system are needed.

In our increasingly tech-saturated world, from mobile apps and health sensors to autonomous cars and factory robots, we expect these devices to seamlessly integrate into our lives, enhancing safety and convenience. However, as these devices proliferate and their autonomy grows, ensuring they provide unobtrusive, yet effective support becomes crucial. The Horizon Europe KST multi-partner project "Distributed Multi-Sensor Systems for Human Safety and Health" (DistriMuSe) intends to support human health and safety by improved sensing of human presence, behaviour, and vital signs in a collaborative or common environment by means of multi-sensor systems, distributed processing and Machine/Deep Learning (ML/DL) techniques. In this paper, we focus on the DistriMuSe's approach on sports performance and health assessment, focusing on monitoring the physical activity of non-professional and hobby athletes, people who like sports and care about their health, elderly healthy people, and subjects affected by neurological disability (e.g., Parkinson's disease). The overall goal is to measure activity and exertion, estimating performance levels and determining maximum effort. We discuss the overall system-of-systems architecture, focusing on the adopted technologies.

Background: Accurately tracking body-composition changes in endurance field settings remains methodologically challenging. This study aimed to evaluate whether changes in subcutaneous adipose tissue (SAT) across a 7-day ultramarathon are better reflected by anthropometric indices than by body mass (BM) alone. Methods: Twenty ultrarunners were assessed using both anthropometric indices and ultrasound measurements of SAT thickness, applying a novel method that distinguishes layers including (DI) versus excluding (DE) embedded fibrous structures. Measurements were obtained before the race and after Stages 4 and 7. Indices included body mass index (BMI), mass index (MII), and waist-to-height ratio (WHtR). Results: Total SAT thickness decreased significantly for both DI (p = 0.001) and DE (p < 0.001). BM, BMI, MII, and WHtR also declined significantly post-race (p < 0.001). SAT reduction was most pronounced at the abdominal and thigh sites. Additionally, ultrarunners with lower DE values exhibited lower fat at the abdomen and distal triceps. BMI was significantly related to DE at the upper and lower abdomen and erector spinae; MII was significantly associated with DE at the upper and lower abdomen; and WHtR correlated with both DE and DI at abdominal and erector spinae sites. BM showed no significant association with any SAT parameter. Conclusions: Ultrasound-derived SAT thickness, in combination with BMI, MII, and WHtR, offers a field-feasible approach to evaluate body-composition change during multistage ultramarathons. In contrast, BM alone does not reliably reflect SAT distribution or loss.

Abstract Background Ultra-endurance events are gaining popularity in multiple exercise disciplines, including cycling. With increasing numbers of ultra-cycling events, aspects influencing participation and performance are of interest to the cycling community. Main body The aim of this narrative review was, therefore, to assess the types of races offered, the characteristics of the cyclists, the fluid and energy balance during the race, the body mass changes after the race, and the parameters that may enhance performance based on existing literature. A literature search was conducted in PubMed, Scopus, and Google Scholar using the search terms ‘ultracycling’, ‘ultra cycling’, ‘ultra-cycling’, ‘ultra-endurance biking’, ‘ultra-bikers’ and ‘prolonged cycling’. The search yielded 948 results, of which 111 were relevant for this review. The studies were classified according to their research focus and the results were summarized. The results demonstrated changes in physiological parameters, immunological and oxidative processes, as well as in fluid and energy balance. While the individual race with the most published studies was the Race Across America, most races were conducted in Europe, and a trend for an increase in European participants in international races was observed. Performance seems to be affected by characteristics such as age and sex but not by anthropometric parameters such as skin fold thickness. The optimum age for the top performance was around 40 years. Most participants in ultra-cycling events were male, but the number of female athletes has been increasing over the past years. Female athletes are understudied due to their later entry and less prominent participation in ultra-cycling races. A post-race energy deficit after ultra-cycling events was observed. Conclusion Future studies need to investigate the causes for the observed optimum race age around 40 years of age as well as the optimum nutritional supply to close the observed energy gap under consideration of the individual race lengths and conditions. Another research gap to be filled by future studies is the development of strategies to tackle inflammatory processes during the race that may persist in the post-race period.

Background: Aerobic fitness level (AFL) is a parameter closely related to a person's overall health. The gold standard of measurement is currently using expensive laboratory equipment. Aims: This study aimed to estimate AFL automatically using data measured with wearables. Methods: AFL was estimated in 2D space. The first dimension is the exertion level, and the second is the body's response to the exertion. Exertion level was determined based on metabolic equivalent calculated for each classified activity using the data of speed and elevation. The activity classification is based on deep neural networks. The body's response estimation is based on heart rate calculated from ECG or PPG. The test set contained 27 subjects. The reference was measured under laboratory conditions using the gold standard method. AFL classification by ACSM guidelines was used. Results: AFL determined by our algorithm were $0.44\pm 0.09,0.50\pm 0.10,0.53\pm 0.09$ , $0.58\pm 0.15$ , and $0.70\pm 0.07$ for the reference classes very poor, poor, fair, good, and excellent, respectively. The correlation between the reference and determined values is 0.76. Conclusion: Our method showed promising results and will be further developed.

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.

The aim of the present study was to examine the physiological and training characteristics in marathon runners with different sport experiences (defined as the number of finishes in marathon races). The anthropometry and physiological characteristics of men recreational endurance runners with three or less finishes in marathon races (novice group, NOV; n = 69, age 43.5 ± 8.0 years) and four or more finishes (experienced group, EXP; n = 66, 45.2 ± 9.4 years) were compared. EXP had faster personal best marathon time (3:44 ± 0:36 vs. 4:20 ± 0:44 h:min, p < 0.001, respectively); lower flexibility (15.9 ± 9.3 vs. 19.3 ± 15.9 cm, p = 0.022), abdominal (20.6 ± 7.9 vs. 23.8 ± 9.0 mm, p = 0.030) and iliac crest skinfold thickness (16.7 ± 6.7 vs. 19.9 ± 7.9 mm, p = 0.013), and body fat assessed by bioimpedance analysis (13.0 ± 4.4 vs. 14.6 ± 4.7%, p = 0.047); more weekly training days (4.6 ± 1.4 vs. 4.1 ± 1.0 days, p = 0.038); and longer weekly running distance (58.8 ± 24.0 vs. 47.2 ± 16.1 km, p = 0.001) than NOV. The findings indicated that long-term marathon training might induce adaptations in endurance performance, body composition, and flexibility.