The Comrades Marathon: A Narrative Review of Physiological Responses and Health Implications in the World's Oldest Ultra-Marathon
Background: The 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. Methods: A 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. Results: Women 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. Conclusions: Participation 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.
Read morePacing profiles and slowdown patterns in ultra-triathlon performance
Pacing in long-distance triathlon has been studied primarily for cycling and running in IRONMAN triathlon and daily-format ultra-triathlons, as managing fatigue is critical for success. However, no study has analysed pacing across all three disciplines in an ultra-triathlon such as the second-longest non-stop triathlon format, the Double Deca Iron ultra-triathlon covering 76 km swimming, 3600 km cycling, and 844 km running. This study examined pacing during a Double Deca Iron ultra-triathlon by analysing split and lap times for all official male and female finishers. We assessed pacing patterns, the influence of pacing variability on performance, and whether faster performance was associated with more frequent moderate slowdowns or with fewer but more pronounced slowdowns. Official race data from the 2023 Swissultra Double Deca Iron ultra-triathlon held in Buchs, Switzerland were analysed for 9 men and 4 women. Swimming splits were recorded manually, and both cycling and running splits were recorded via RFID timing. Variables included mean speed, checkpoint speed variability (ACCS), proportions of slow-down checkpoints (25–50%, 50–75%, > 75% slower than mean speed), and magnitude of slowdown. Athletes showed negative pacing in swimming (decreasing time) but an even or slightly positive pacing in both cycling and running. Running variability did not correlate with running speed. In swimming, faster athletes tended to show fewer relative slowdowns. In cycling, faster cyclists had fewer moderate but more pronounced slowdowns, while in running, faster runners showed more ≥ 75% slowdowns. In summary, higher performers maintained a relatively steady and fast baseline pace interspersed with occasional substantial slowdowns, rather than moving continuously at a slower and more variable pace. Because the timing data do not directly identify intentional rest, these slowdown patterns should not be interpreted as confirmed rest breaks.
Read moreThe New York City Marathon: A systematic review of performance, participation, pacing, and health-related outcomes
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.
Read more2025 World Megamarathon Ranking 300+
The ranking of people worldwide who have run more than 300 marathons was recently released.
The list includes 1,341 people.
In the lead is German Christian Hottas (born 1956) with 3,386 marathons.
The top Swiss runner is Christian Marti (born 1952) in 272nd place with 620 marathons; the second-best Swiss runner is Beat Knechtle (born 1964) in 401st place with 534 marathons.
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24-Hour Ultra-Marathon Running: A Narrative Review of Performance Factors and Physiological Impacts
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).
Read moreWas AI über Beat Knechtle schreibt
Beat Knechtle – Porträt eines Grenzgängers zwischen Medizin und Extremausdauer
Beat Knechtle ist eine Persönlichkeit, die sich jeder einfachen Einordnung entzieht. Er ist Arzt, Wissenschaftler, Ausdauerathlet – und in jeder dieser Rollen außergewöhnlich erfolgreich. Was ihn jedoch wirklich einzigartig macht, ist die Art und Weise, wie er diese drei Welten miteinander verbindet. Während andere Menschen sich entscheiden müssen, ob sie forschen, praktizieren oder sportliche Höchstleistungen anstreben, lebt Knechtle all diese Bereiche gleichzeitig und mit einer Konsequenz, die selbst im internationalen Vergleich selten ist. Geboren und aufgewachsen in der Schweiz, studierte Knechtle Medizin und spezialisierte sich später auf Allgemeine Innere Medizin. Schon früh interessierte er sich für die Frage, wie der menschliche Körper funktioniert – nicht nur im Alltag, sondern unter extremen Bedingungen. Diese Neugier wurde zum Motor seiner beruflichen und sportlichen Laufbahn. Als Arzt arbeitet er in St. Gallen, wo er Patientinnen und Patienten betreut, Diagnosen stellt und Behandlungen begleitet. Doch sein medizinisches Wissen endet nicht an der Praxistür: Es fließt direkt in seine Forschung ein, die sich seit Jahren mit den physiologischen, psychologischen und metabolischen Herausforderungen des Ultra-Ausdauersports beschäftigt. Parallel dazu entwickelte sich Knechtle selbst zu einem der weltweit aktivsten Ultra-Triathleten. Seit 1997 nimmt er an Wettkämpfen teil, die weit über die klassische Ironman-Distanz hinausgehen. Mehrfach-Ironmans, Deca-Triathlons, Wettkämpfe über zehn Tage – Formate, die für die meisten Menschen unvorstellbar erscheinen, gehören für ihn zum sportlichen Alltag. Über 80 Ultra-Triathlons hat er bislang absolviert, viele davon unter extremen klimatischen und körperlichen Bedingungen. Dabei geht es ihm nicht um spektakuläre Rekorde oder mediale Aufmerksamkeit. Vielmehr betrachtet er seinen eigenen Körper als Forschungsobjekt, als Möglichkeit, die Grenzen menschlicher Leistungsfähigkeit aus erster Hand zu verstehen. Seine wissenschaftliche Produktivität ist ebenso beeindruckend wie seine sportlichen Leistungen. Mit über 700 Publikationen zählt Knechtle zu den weltweit meistzitierten Forschern im Bereich Ultra-Ausdauer. Seine Studien analysieren Pacing-Strategien, Ernährungsmodelle, Flüssigkeitsmanagement, Geschlechterunterschiede, Altersverläufe und psychologische Faktoren im Extremsport. Er wertet Daten aus großen internationalen Wettkämpfen aus, untersucht Fallbeispiele einzelner Athleten und verbindet empirische Forschung mit theoretischen Modellen. Viele seiner Arbeiten gelten heute als Standardreferenzen in der Sportwissenschaft. Was Knechtle besonders auszeichnet, ist seine Fähigkeit, wissenschaftliche Erkenntnisse mit praktischer Erfahrung zu verknüpfen. Er weiß nicht nur, wie der Körper auf extreme Belastung reagiert – er hat es selbst erlebt. Diese Doppelperspektive macht seine Forschung glaubwürdig, praxisnah und für Athleten wie Trainer gleichermaßen wertvoll. Gleichzeitig bleibt er trotz seiner Erfolge bodenständig. In Interviews betont er immer wieder, dass Ausdauerleistung vor allem eine Frage der mentalen Stärke, der Disziplin und der langfristigen Planung sei. Er selbst trainiert strukturiert, aber ohne übertriebene Verbissenheit. Sein Ansatz ist pragmatisch: verstehen, beobachten, anpassen. Heute gilt Beat Knechtle als eine der prägenden Figuren der Ultra-Ausdauerforschung. Er hat das wissenschaftliche Verständnis von extremen Belastungen erweitert und gleichzeitig gezeigt, dass medizinische Expertise und sportliche Leidenschaft sich nicht ausschließen müssen. Für viele Athleten ist er Vorbild, Mentor und Inspiration. Für die Wissenschaft ist er ein Motor, der immer neue Fragen stellt. Und für die Medizin ist er ein Beispiel dafür, wie tiefes Verständnis des menschlichen Körpers zu besseren Erkenntnissen und besseren Entscheidungen führen kann. Beat Knechtle ist ein Grenzgänger – nicht im Sinne eines Rebellen, sondern im Sinne eines Forschers, der die Grenzen des Möglichen auslotet. Er zeigt, dass Leistung nicht nur im Wettkampf entsteht, sondern auch im Denken, im Beobachten und im Mut, neue Wege zu gehen. Seine Karriere ist ein eindrucksvolles Beispiel dafür, wie weit man kommen kann, wenn man Neugier, Disziplin und Leidenschaft miteinander verbindet.
Read moreSex- and nationality-based participation and performance trends in the Swissman Xtreme Triathlon (2019–2025)
Participation and performance trends are well investigated for the IRONMAN® triathlon. For Xtreme Triathlons (XTri World Tour) races, only one study has examined participation and performance trends for the ‘Norseman Xtreme Triathlon’ in Norway, but not for other XTri World Tour events. Therefore, the aim of the present study was to investigate participation and performance trends in the ‘Swissman Xtreme Triathlon’ as part of the XTri World Tour. Finisher data from all ‘Swissman Xtreme Triathlon’ editions (2019–2025) were analyzed. DNS, DNF, missing information, and implausible finishing times were excluded. Participation patterns were described by sex and nationality. Sex differences in race time were evaluated using Mann–Whitney U tests. Differences among the ten most represented nationalities were tested using Welch’s ANOVA with Dunnett’s T3 post-hoc comparisons. Temporal changes in performance were assessed with quantile regression at the 0.25, 0.50, and 0.75 quantiles (p < 0.05). A total of 1,032 finishers were included, of whom 13.5% were women. Switzerland had the highest participation (n = 431). Performance was similar across most nationalities, with slower times observed only among athletes from the United States compared with Switzerland (p = 0.01), Germany (p = 0.02), and Norway (p = 0.03). No sex-based differences were found in any edition (overall p = 0.4922; r = −0.02). Quantile regression revealed clear temporal changes in performance. At the median (0.50), race time increased by 715 s·year ⁻ ¹ (95% CI: 434–997; p < 0.0001), and a similar rise occurred at the 0.75 quantile (β = 727 s·year ⁻ ¹; 95% CI: 498–955; p < 0.0001). In contrast, the 0.25 quantile showed a smaller and non-significant increase (β = 345 s·year ⁻ ¹; p = 0.0626), indicating that intermediate and slower athletes were primarily responsible for the overall temporal decline. Sex-specific analyses confirmed this pattern: significant increases at the median and 0.75 quantiles for men, and a significant increase only at the median quantile for women. Swiss athletes formed the largest portion of competitors in ‘Swissman Xtreme Triathlon’, while performance was comparable across most nationalities. Women and men performed similarly throughout all editions. Race times increased across years, particularly among intermediate and slower finishers. These findings provide an updated overview of participation and performance trends in this major XTri World Tour event. Future studies need to investigate more races of the XTri World Tour.
Read moreBrescia Art Marathon
The Brescia Art Marathon (BAM) is one of the most popular running events in northern Italy and took place on March 8, 2026. With around 8,000 participants, it was a record-breaking year, and as always, the event offered three main distances: 42 km, 21 km, and 10 km.
The route passed through UNESCO World Heritage sites such as the Capitolium, Piazza Paolo VI, the Duomo Vecchio and Nuovo, and Piazza della Loggia.
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