Ultramarathon Race Research Articles

Submaximal force–velocity relationships during mountain ultramarathon: Data from the field

ABSTRACT This study presents a novel method for evaluating the submaximal velocity-force (V(F)) relationship in mountain ultramarathon races using crowdsourced data from Strava.com. The dataset includes positional data from 408 participants of the 171-km UTMB® 2023 race (9,850-m D+). The race was divided into 100-m segments. The mean net propulsive force and velocity were computed for each segment to describe the submaximal V(F) relationship as a rational function of three parameters. F1: propulsive force at 1 m · s−1; V0: theoretical maximum velocity on flat terrain; C: curvature parameter (the lower C, the more linear the V(F) relationship). The V(F) profile parameters were found to be F1 = 1.80 ± 0.33 N · kg−1, V0 = 2.36 ± 0.42 m · s−1, and C = 0.66 ± 1.81, with good independence between the parameters within a group of homogeneous performance. The best athletes had the highest F1, V0, and C values. V(F) parameters were affected by fatigue during the race, with decreases of 20.9%, 32.0%, and 59.8% between the first and second parts of the race respectively. These findings suggest that the V(F) relationship is an interesting original approach for studying performance and fatigability during mountain ultra-endurance races.

Road and trail running from 5 km to an ultra-marathon – trends in Switzerland from 1999 to 2019

PurposeThis study aimed to verify participation and performance in all road and trail-based races in Switzerland over two decades (1999–2019).MethodsThis is a secondary data-based study. We used 1,149,182 race records (788,818 from men and 360,364 from women) from 407,944 unique finishers of the 5 km, 10 km, half-marathon, marathon, and ultra-marathon races in Switzerland, between 1999 and 2019. Data included the athletes’ genders, ages, race distances, and types of races (road or trail). The mento- women ratio was calculated and box plots were used to present differences according to gender, age groups, and race distances in both terrains. Differences between the groups were calculated.ResultsThe men-to-women ratio has generally decreased in all race distances over the years. Runners competing in roadbased races were faster than those in a trail run in all distances. Men had faster finish times than women independent of age, except those competing in 10 km trail races. In road-based races, the men-to-women ratio was higher among older marathoners, while for trail runs, a higher men-to-women ratio was shown for older half-marathoners and participants in 10 km races. For 5 km, 10 km, half-marathon, and ultra-marathon races, a decrease in running speed differences was shown until the age of 50 years.ConclusionsIn Switzerland, most of the runners competed in road-based races, but the interest in trail running has increased. The men-to-women ratio declined over time, which could show an increase in the interest of women to participate in endurance activities.

Cortisol and insulin behaviors during an ultramarathon event: are they real markers of extreme exertion?

The current work aimed to describe and compare the cortisol and insulin concentrations behavior and rate of perceived exertion (RPE) during a 115 km ultramarathon race. Nine ultrarunners (eight males) were evaluated six times (0, 37, 60, 76, 89 and 115 km). At each moment, saliva samples (for cortisol and insulin assessment) and RPE (CR10 scale) were collected. Statistical analysis included correlation, one-way repeated measure ANOVA, and Statistical Parametric Mapping to define discrete and continues changes and compare cortisol, insulin and RPE profiles. Our main findings revealed an early peak in cortisol and RPE, accompanied by a decline in insulin responses (402±49 min of the race, P<0.05). Cortisol and insulin only showed magnitude differences with inverse behaviors until ~6% (7 km) of the ultramarathon duration. Cortisol and RPE presented similar behaviors, rising from the beginning of the race and remaining elevated throughout the race (η2=0.91 and η2=1.0, P<0.001). Insulin levels decreased when the race started, remaining below 60% of baseline values from the midpoint to the end of the race (P=0.04). The study showed an imbalance in the catabolic/anabolic hormone profile during an ultramarathon race, with a prominence in catabolic state. It should be considered in the ultramarathon races preparation and participation due to its possible detrimental effect on the athlete's health.

Sex, training variables, history of chronic disease, and chronic injury are risk factors associated with a history of exercise-associated muscle cramping in 10,973 ultramarathon race entrants: a safer XXXVIII study.

The prevalence of a history of exercise-associated muscle cramping (hEAMC) among ultramarathon runners is high. While the Comrades is one of the most popular mass community-based participation ultramarathons (90 km) globally, research on the epidemiology, clinical characteristics, and risk factors of entrants' lifetime hEAMC are scarce. This research aimed to describe the epidemiology, clinical characteristics, and risk factors of hEAMC among Comrades Marathon entrants. This was a retrospective, cross-sectional study in which 10973 race entrants of the 2022 Comrades Marathon participated. Entrants completed a prerace medical screening questionnaire that included questions related to the lifetime prevalence (%; 95% CI), severity, treatment and risk factors (demographics, training/racing variables, chronic disease/allergies, injury) for EAMC. One thousand five hundred eighty-two entrants reported hEAMC in their lifetime (14.4%; 95% CI: 13.77-15.09). There was a significantly (P<0.01) higher prevalence of male (16.10%; 95% CI:15.34-16.90) than female (8.31%; 95% CI: 7.27-9.50) entrants with hEAMC (PR=1.94; 95% CI:1.68-2.23). The prevalence of hEAMC was highest in entrants with a: 1) 1 disease increase in composite disease score (PR=1.31; 95% CI:1.25-1.39); 2) history of collapse (PR=1.87; 95% CI 1.47-2.38); 3) past chronic musculoskeletal (MSK) injury (PR=1.71; 95% CI 1.50-1.94); and 4) MSK injury in the previous 12 months (PR=2.38;95% CI: 2.05-2.77). Training-related risk factors included an increase of 10 km weekly running distance (PR=0.97; 95% CI:0.95-0.99) and a training pace increase of 1min/ km (slower) (PR=1.07; 95% CI:1.03-1.12). Future research should investigate the causal relationship between risk factors identified and hEAMC in ultramarathon runners. Findings from this study could assist in effective anticipation and adequate planning for treating EAMC encounters during community-based mass participation events.

Risk factors associated with medical encounters in ultramarathon race starters – Data from 103,131 race starters over 90 km: SAFER XLI

ObjectivesTo identify the risk factors associated with all medical encounters (MEs) and serious/life-threatening MEs (SLMEs) during the Comrades Marathon. DesignProspective cohort study, with cross-sectional analyses. MethodsDuring the 2014–2019 Comrades Marathon, all MEs (including SLMEs) were recorded in 103,131 starters. For both all MEs and SLMEs, the following risk factors were explored: sex, age, route (“up” vs. “down” race), previous Comrades experience (yes/no), wet-blub globe temperature (WBGT) and race pace. Incidence (per 1000 starters; 95%CI), and the incidence ratio (IR; 95%CI) are presented. ResultsFor all MEs, being female was a significant risk factor (females vs. males IR = 1.47, p < 0.0001), and age was only marginally significant (p = 0.0167). Therefore factors for all MEs were adjusted for sex. Other factors significantly associated with all MEs were: higher WBGT (highest WBGT compared to lowest, IR = 1.33, p = 0.0003), race pace (highest risk for those who finish either among the first quarter [IR = 1.49] or last quarter [IR = 1.46] compared to middle pace; p < 0.0001) and the route (“down” vs. “up”: IR = 1.11; p = 0.0181). Factors associated with higher risk for SLMEs were: females (IR = 1.9; p = 0.0003), “down” vs. “up” route (IR = 1.37; p = 0.0306) and race pace (slower and faster runners vs. mid (6.4–7.1 min/km) race pace category (IR > 2.1, p < 0.0001)). ConclusionsIntrinsic (female, faster and slower race pace) and extrinsic (higher WBGT and the “down” route) are novel risk factors associated with all MEs at this event. These can be considered by the race organizers and the medical team to develop and implement prevention strategies.

Nutritional strategies for single and multi-stage ultra-marathon training and racing: from theory to practice

Nutritional strategies for single and multi-stage ultra-marathon training and racing: from theory to practice

Exploring the scope and applications of anti-doping measures in ultramarathon: an analysis of the positions of ultramarathon race organizers.

With ultramarathon attracting burgeoning interest, evidence has emerged about doping behaviors. However, currently, research into the anti-doping policy landscape and the adoption of testing and athlete surveillance is limited, including the applicability of rubric from the World Anti-Doping Agency (WADA) and National Anti-Doping Organizations (NADOs). Consequently, it remains unclear if anti-doping provisions have been developed and enforced in ultramarathon, which is a timely consideration given growth in the sport. This study gathered perspectives on anti-doping and testing procedures from ultramarathon race organizers (UMROs). To that end, a sample of n = 35 prominent competitions was compiled using web materials and community engagement, encompassing elite and amateur entrants, diverse course designs, and prize money opportunities. Data-gathering was conducted across two phases between November and December 2023, with an initial review of UMRO web resources. Subsequently, UMROs were contacted via email to validate or ascertain their anti-doping and testing policies. Insights from UMRO respondents were reviewed and coded. UMROs who did not reply were excluded from the analysis. Based on this methodology, the positions of n = 17 UMROs were captured, covering 159 ultramarathon races and approximately 96,500 annual participants. Of these, n = 8 UMROs did not have a self-developed policy and their rubric was pursuant to external authorities like WADA and NADOs. n = 4 had created a specific proprietary policy, which often incorporated WADO or NADO materials. The remaining n = 5 UMROs reported no anti-doping controls were in place at the time of the study. There was also notable heterogeneity in testing and surveillance, ranging from rigorous procedures to an absence of protocols. Interestingly, none of the included UMROs explicitly reported that they had enacted anti-doping measures against athletes. Various determinants could inform these regulatory inconsistencies across UMROs, such as financial constraints, infrastructural and logistical barriers, cultural factors, and the lack of a unifying international federation in ultramarathon. Given the disparate approaches identified in our results, greater cooperation and education may be necessary to enhance understanding about the implications of doping and advance cohesive frameworks. This should involve collaborations with WADA and NADOs to promote best-practices and evidence-based exchanges within the community.

Blood Pressure and Central Arterial Stiffness before and after a 161-km Ultra-Endurance Race

BACKGROUND: Competing in ultra-endurance running events (&gt;42.2 km) is a tremendous physiological stressor. Training for and competing in these events may be detrimental to cardiovascular (CV) health. However, previous findings on acute changes in key CV health measures like blood pressure (BP) and central arterial stiffness after a race remain equivocal. Therefore, we aimed to characterize the acute CV response to an ultra-endurance race. We hypothesized that BP would decrease while central arterial stiffness would increase following the race. Methods: We measured supine BP with an automated brachial cuff and carotid-to-femoral pulse wave velocity (cfPWV - index of central arterial stiffness) with applanation tonometry (SphygmoCor XCEL, AtCor Medical) among 41 finishers (9F/32M; Age: 44 ± 10 years; BMI: 22.7 ± 1.8 kg/m2) of the 2023 161-km Western States Endurance Run (WSER). Measures were taken 1–3 days before (pre) and ≤1 hour after race completion (post). We present data as mean ± SD after confirming normality using Shapiro-Wilk tests (α ≥ 0.05). We assessed differences between pre- and post- systolic BP (SBP), mean BP (MBP), diastolic BP (DBP), cfPWV, and cfPWV normalized to MBP using paired, two-tailed t-tests (α &lt; 0.05). The magnitude of the difference between time points was represented as Cohen’s d ( d) effect sizes. Results: After the race, there was a significant decrease in SBP (129 ± 9 vs. 122 ± 10 mmHg, P &lt; 0.001, d = 0.78), MBP (94 ± 7 vs. 89 ± 10 mmHg, P &lt; 0.001, d = 0.58), and DBP (77 ± 7 vs. 74 ± 8, P = 0.02, d = 0.38) but no change in cfPWV (6.4 ± 1.0 vs. 6.2 ± 0.8 m/s, P = 0.10, d = 0.26) or cfPWV normalized to MBP (0.07 ± 0.01 vs. 0.07 ± 0.01 (m/s)/mmHg, P = 0.83, d = 0.00). CONCLUSION: We found that systolic, mean, and diastolic pressure were all lower after the 161-km WSER, but cfPWV did not change. These findings suggest that running a 161-km ultra-marathon race acutely lowers BP but does not affect central arterial stiffness. Further research is needed to understand the effect of chronic ultra-endurance training and competition on cardiovascular health. FUNDING INFORMATION: Western States Endurance Run Medical Research Program (GJG), National Institutes of Health K01HL160772 (JCW), American Heart Association 23CDA1037938 (JCW). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Training Regimen of an Elite Ultramarathon Runner: A Case Study of What Led Up to the 24-Hour World-Record Run.

Ultramarathon running has gained popularity over several decades. Although there has been considerable research on training for other running events, from the 100-m to the marathon at 26.2 miles (42.2km), there is little evidence on best practices for ultramarathons, where distances potentially exceed 100 miles (160.9km). In this case study, we examine the training regimen of an elite ultramarathon runner who broke 8 world records in 2021 and 2022, including the 24-hour run in which he ran 319.6km in September 2022. Training data from December 28, 2020, to September 17, 2022, were collected from the Strava application database (recorded on Coros watch) and analyzed using Microsoft Excel and Tableau. Our subject completed 5 training blocks, with volume per training block averaging 172.1 to 263km/wk. Peak running volume per training block occurred on average 3.2weeks out from races and reached a maximum of 378km/wk. Recovery was emphasized the week following a race, with less running (19km/wk) and more cross-training. Interval-type workouts (1- to 10-km repeats) were completed throughout training blocks. The average pace during the 24-hour world-record run was 4 minutes and 30seconds per kilometer (4:30/km), closely matching the overall average training pace. These findings suggest that training for ultramarathon races should include high-volume running at varied paces and intensity with cross-training to avoid injuries. We hope that this evidence helps athletes understand how to prepare for these ultraendurance events.

Are pre‐race serum blood biomarkers associated with the 24‐h ultramarathon race performance?

AbstractThe 24‐h ultramarathon (UM) race is one of the most demanding competitive sports in terms of muscular and physiological exertion. In this context, predictors of UM athletes' physical performance are in high demand; however, data on the predictive capabilities of hematological variables are still sparse. In the present paper, we retrospectively took into consideration the pre‐race blood biomarker levels (including basic blood count, leukocyte subpopulations, markers of inflammation and organ function, metabolic profile, and electrolytes) of 50 UM athletes (M = 33, F = 17) who completed a 24‐h competition in order to identify a combination of analytes capable of predicting the athletic performance in terms of distance covered during the 24‐h run. The multiple regression analysis produced a model that explained a significant portion of the variance in the dependent variable, with an adjusted R‐squared value of 0.783 (F(13, 36) = 14.58, p &lt; 0.001). A greater race distance was correlated with higher pre‐race values of hematocrit, lactate dehydrogenase (LDH), total cholesterol, HDL/LDL ratio, and triglycerides and lower levels of monocytes, eosinophils, alanine aminotransferase (ALT), gamma‐glutamyl transferase (GGT), total proteins, and sodium. This study represents the first of its kind conducted on 24‐h UM athletes that investigated the association between blood markers and endurance performance. Our model, given its promising predictive power, would serve as a starting point that will require refinement and integration with other traditional performance prediction measures, in order to support athletes and coaches in better managing the training loads during the race‐approaching phases.

Prevalence of Drug Use in Ultraendurance Athletes.

In competitive sport, classic methods of measuring drug prevalence, such as doping controls or questionnaires, are challenging. Here we describe a novel urine sampling method to measure drug use in athletes. We hypothesize that the prevalence of drug use in ultramarathon runners is measured more accurately with our sampling method than randomized-response questionnaires. Urine samples and associated demographic data were collected from male participants using blind, automated urinals at the start of ultramarathon races. Various nonprohibited and prohibited substances were subsequently screened. Concomitantly, 2931 male and female runners participating in the same ultramarathons completed an anonymized, randomized-response questionnaire regarding drug use. Among 412 individual urine samples, 205 (49.8%) contained at least one substance, and 16.3% of the samples contained one or more prohibited substances. Substances detected in urine included nonsteroid anti-inflammatory drugs (NSAID) (22.1%), acetaminophen (15.5%), opioids (6.6%), diuretics (4.9%), hypnotics (4.4%), glucocorticoids (2.7%), beta-2 agonists (2.2%), cannabinoids (1.9%), and stimulants (1.2%). None of the samples contained erythropoietin-receptor agonists or suspicious testosterone. Drug use was not associated with the participants' characteristics or ranking. Respondents to the questionnaire reported using acetaminophen (13.6%) and NSAID (12.9%); however, no prohibited substances were declared. There was a high prevalence of drug use among male ultramarathon runners, in particular, NSAID and painkillers; however, performance-enhancing drugs were marginally used. Blind urine sampling highlighted prohibited drug use not declared in questionnaires, and it is useful to assess the prevalence of drug use and/or doping in competitive athletes.

The severity and dynamics of changes in the serum concentration of biochemical markers of muscle tissue damage in an experienced ultramarathon runner after overcoming a distance of 165 km against the background of continuing physical activity

Purpose: to determine the severity and dynamics of changes in the concentration of biochemical markers of muscle tissue damage in the blood serum of an experienced ultramarathon runner after overcoming a distance of 165 kilometers.Materials and methods: measurement of serum concentrations of markers of muscle tissue damage (aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatine kinase (CK), creatine kinase MB (CK-MB), myoglobin) in serum before and 16 and 144 hours after ultramarathon in an experienced runner (age 36, height 186 cm, weight 76 kg, body mass index 21.96).Results: 16 hours after the end of the race, extremely high levels of AST, ALT, CK, CK-MB and myoglobin were observed, the combination of which indicates severe rhabdomyolysis. After 144 hours, a decrease in the level of all markers of muscle tissue damage, including myoglobin, was noted, however, they continued to remain significantly higher than the reference values. At the same time, the athlete did not have any significant pathological symptoms, and he continued to train in the recovery mode.Conclusion: ultramarathon races lead to significant muscle damage, which can lead to rhabdomyolysis. Its severity may not correlate with any significant clinical manifestations.

Increase of high sensitivity cardiac troponin I and NT-proBNP in competitive athletes after a 50-km ultramarathon race: physiological adaptation or myocardial injury?

Increase of high sensitivity cardiac troponin I and NT-proBNP in competitive athletes after a 50-km ultramarathon race: physiological adaptation or myocardial injury?

Sleep in marathon and ultramarathon runners: a brief narrative review.

Sleep is considered a fundamental biological function in humans necessary for recovery from daily physical activities. Considering the increasing popularity of long-distance running and participation in races such as marathons and ultramarathons, the aim of the present study was to review the relationship of such strenuous physical activities with sleep. A search of Scopus was performed on 24/6/2023 using the syntax [ABS (sleep) AND ABS (marathon)] to identify relevant papers, the references of which were hand-searched to find additional sources. Optimal sleep has been shown to affect injury prevention and susceptibility to infection positively. In turn, participation in a marathon race may influence nocturnal autonomic modulation and disturb homeostasis. Ultramarathon races may have such a long duration that results in sleep deprivation even for several days, where sleep duration is quite below the physiological range. It seems that for ultramarathons of short duration, continuous running and sleep deprivation are beneficial for performance. In contrast, for races longer than 200 miles, it is necessary to develop sleep strategies to sustain performance. In summary, the longer the distance of a running race, the greater the importance of an optimal sleep for race performance as well as the impact of a race on sleep.

Blood biochemical changes after dramatic increase in running training volume: exploratory study in 3 elite soldiers.

Background: Ultra-Endurance running training is a powerful stressor for all biological systems and depends mainly on its volume and intensity. Although the high physical demands, soldiers are an unstudied group and information on exercise indicators are essential. Objective: This study aimed to observe the changes in serum biochemical indicators in previously endurance trained elite soldiers after a 17-week training program with a dramatic increase in running volume. Methods: Three subjects (#1: 26 years, 169,5cm; #2: 27 years, 167,9cm; #3: 27 years, 180,7cm) running daily between 10-12 km/day, increased their running volume to prepare the participation in a 100-km ultramarathon race. For 17 weeks the training program included 10-12 sessions per week, corresponding to 200-260 km. Average daily running volume was 35.8±6.2 km. Blood samples were taken for analysis of urea, creatinine, glucose, cholesterol and triglycerides, AST, ALT, CK, aldolase, Na, chloride, P, Ca, K, Fe, Mg and cortisol. Results: Despite a marked drop in iron and a rise in phosphorus, the overall mineral status remained within laboratory reference values. ALT, AST, Aldolase showed slight changes while a marked increase was found in CK. Creatinine decreased and urea maintained the high starting values. Changes of glucose, cholesterol and triglycerides had no clinical significance. After the 17-week the cortisol increased to outside of the reference values in two participants. Conclusion: This study shows that a dramatic increase in running training volume experienced by previous trained runners is mainly reflected in basal blood chemistry through the reduction of iron and creatinine and increase of cortisol.

Racing Experiences of Recreational Distance Runners following Omnivorous, Vegetarian, and Vegan Diets (Part B)-Results from the NURMI Study (Step 2).

The potential running or endurance performance difference based on following different general types of diets, such as omnivorous, vegetarian, or vegan, remains questionable. Several underlying modifiable factors of long-distance running performance, especially runner training behaviors and experience, diminish the clarity of results when analyzing dietary subgroups. Based on the cross-sectional design (survey), the NURMI Study Step 2 aimed to investigate a plethora of training behaviors among recreational long-distance running athletes and the relationship of general diet types with best time race performance. The statistical analysis was based on Chi-squared and Wilcoxon tests. The final sample (n = 245) included fit recreational long-distance runners following an omnivorous diet (n = 109), a vegetarian diet (n = 45), or a vegan diet (n = 91). Significant differences were found between the dietary subgroups in body mass index (p = 0.001), sex (p = 0.004), marital status (p = 0.029), and running-related motivations for well-being (p < 0.05) but not in age (p = 0.054). No significant difference was found for best time half-marathon, marathon, and/or ultra-marathon race performance based on diet type (p > 0.05). Whether the vegan diet is associated with enhanced endurance performance remains unclear. Although, the present results are suggestive that 100% plant-based (vegan) nutrition is compatible with distance running performance at the least.

Risk factors associated with gradual onset running-related injuries in 5770 ultramarathon race entrants - SAFER XXXII.

There is limited evidence available on contributing factors for gradual onset running-related injuries (GORRIs) in ultramarathon runners. The aim was to determine if selected risk factors were associated with a history of GORRIs in 90-km ultramarathon race entrants. Descriptive cross-sectional study. GORRI and medical data using an online pre-race medical screening tool was collected from 5770 consenting race entrants from the 2018 90-km Comrades Marathon. Selected risk factors associated with 12-months history of GORRIs (age, sex, training, chronic diseases and allergies) were analyzed using a multiple model (Poisson regression). Prevalence and prevalence ratios (PR, 95% CIs) are reported. The overall 12-month prevalence of GORRIs was 11.6% (95% CI: 10.8-12.5) and this was higher in females versus males (PR=1.6; 1.4-1.9) (P<0.0001). Novel independent risk factors associated with a history of GORRIs were: history of chronic disease (PR=1.3; P=0.0063); history of allergies (PR=1.7 increased risk for every disease; P<0.0001); fewer training sessions/week (PR=0.8 decreased risk for every two additional training sessions per week; P=0.0005); and increased number of years as a recreational runner (PR=1.1 increased risk per 5 years of running; P=0.0158). There is a complex interaction between the internal and external risk factors associated with GORRIs in 90-km distance runners. These data can inform injury prevention programs targeted at subgroups of ultradistance runners.

Comparison of the differences in iron and anemia-related markers by ultramarathon distance.

Iron and anemia-related markers in long-distance runners have mostly been investigated following single distance marathons, with contradictory findings. This study compared iron and anemia-related markers according to marathon distance. Iron and anemia-related markers were analyzed from blood samples of healthy, adult male (aged ≥40-60 years) long-distance runners before and after ultramarathon races of 100 km (N.=14), 308 km (N.=14), and 622 km (N.=10). Fe, total iron-binding capacity (TIBC), unsaturated iron-binding capacity (UIBC), transferrin saturation, ferritin, high-sensitivity C-reactive protein (hs-CRP), white blood cell (WBC), red blood cell (RBC), hemoglobin (Hb), and hematocrit (Hct) levels were analyzed. On completion of all races, the iron levels and transferrin saturation decreased (P<0.05), while the ferritin and hs-CRP levels and WBC counts significantly increased (P<0.05). The Hb concentrations increased after the 100-km race (P<0.05), although the Hb levels and Hct decreased after the 308- and 622-km races (P<0.05). The highest-to-lowest levels of unsaturated iron-binding capacity were found following the 100-km, 622-km, and 308-km races, whereas those of the RBC count were found following the 622-km, 100-km, and 308-km races. Ferritin levels were significantly higher following the 308-km race than after the 100-km race (P<0.05); hs-CRP levels in the 308- and 622-km races were higher than those in the 100-km race. Ferritin levels increased due to inflammation following distance races, and runners experienced transient iron deficiency without anemia. However, the differences in iron and anemia-related markers according to the ultramarathon distance remain unclear.

Running for Your Life: Metabolic Effects of a 160.9/230 km Non-Stop Ultramarathon Race on Body Composition, Inflammation, Heart Function, and Nutritional Parameters.

Moderate endurance exercise leads to an improvement in cardiovascular performance, stress resilience, and blood function. However, the influence of chronic endurance exercise over several hours or days is still largely unclear. We examined the influence of a non-stop 160.9/230 km ultramarathon on body composition, stress/cardiac response, and nutrition parameters. Blood samples were drawn before (pre) and after the race (post) and analyzed for ghrelin, insulin, irisin, glucagon, cortisol, kynurenine, neopterin, and total antioxidant capacity. Additional measurements included heart function by echocardiography, nutrition questionnaires, and body impedance analyses. Of the 28 included ultra-runners (7f/21m), 16 participants dropped out during the race. The remaining 12 finishers (2f/10m) showed depletion of antioxidative capacities and increased inflammation/stress (neopterin/cortisol), while energy metabolism (insulin/glucagon/ghrelin) remained unchanged despite a high negative energy balance. Free fat mass, protein, and mineral content decreased and echocardiography revealed a lower stroke volume, left end diastolic volume, and ejection fraction post race. Optimizing nutrition (high-density protein-rich diet) during the race may attenuate the observed catabolic and inflammatory effects induced by ultramarathon running. As a rapidly growing discipline, new strategies for health prevention and extensive monitoring are needed to optimize the athletes' performance.

Sex-specific Physiological Responses To Ultramarathon

PURPOSE. Despite a growing body of literature on the physiological response to ultra-marathon, there is a paucity of data in female athletes. This study assessed the female physiological response to ultra-marathon and compared perturbations to a group of race- and performance-matched males. METHODS. Data were examined from a cohort of 53 individuals who contested an ultra-marathon trail race at the Ultra Trail du Mont-Blanc (UTMB®) in 2018/19. Before and within 2-h of the finish, subjects underwent physiological assessments including: Blood sampling (creatine kinase, CK-MB; cardiac troponin I, cTnI; brain natriuretic peptide, BNP, creatinine, Cr); pulmonary function testing (spirometric indices, exhaled NO, diffusing capacities, mouth pressures); and transthoracic ultrasound (lung comet tails, cardiac function). Data from eight female finishers (age = 36.6 ± 6.9 y; finish time = 30:57 ± 11:36 hh:mm) were compared to a group of eight time-matched males (age = 40.3 ± 8.3 y; finish time = 30:46 ± 10:32 hh:mm). RESULTS. Females exhibited significant post-race hematological changes in BNP (25.8 ± 14.6 vs. 140.9 ± 102.7 pg/mL; p = 0.017) and CK-MB (3.3 ± 2.4 vs. 74.6 ± 49.6 IU/L; p = 0.005), whereas males exhibited significant post-race hematological changes in BNP (26.6 ± 17.5 vs. 96.4 ± 51.9 pg/mL; p = 0.007), CK-MB (7.2 ± 3.9 vs. 108.8 ± 37.4 IU/L; p < 0.001), cTnI (0.01 ± 0.01 vs. 0.05 ± 0.05 ng/mL; p = 0.033), and Cr (1.06 ± 0.19 vs. 1.23 ± 0.24 mg/dL; p = 0.014). Post-race peak expiratory flows decreased in both groups; however, only males exhibited reductions in lung diffusing capacities (DLCO = 34.4 ± 5.7 vs. 29.2 ± 6.9 mL/min/mmHg, p = 0.002; DLNO = 179.1 ± 26.2 vs. 152.8 ± 33.4 mL/min/mmHg, p = 0.001) and pulmonary capillary blood volume (77.4 ± 16.7 vs. 57.3 ± 16.1 mL; p < 0.001). Males, but not females, exhibited a significant post-race increase in the number of lung comet tails (2.4 ± 2.2 vs. 8.3 ± 2.7; p = 0.001). CONCLUSION. Participation in an ultra-marathon negatively affects numerous aspects of physiological function but evokes more extensive perturbations in males compared to females with similar race performances.