Heart rate variability in ultra-trail runners

Postprint (published version

Validity of the Polar V800 monitor for measuring heart rate variability in mountain running route conditions

PURPOSE: This study was conducted to test, in mountain running route conditions, the accuracy of the Polar V800 monitor as a suitable device for monitoring the heart rate variability (HRV) of runners. METHOD: Eighteen healthy subjects ran a route that included a range of running slopes such as those encountered in trail and ultra-trail races. The comparative study of a V800 and a Holter SEER 12 ECG Recorder included the analysis of RR time series and short-term HRV analysis. A correction algorithm was designed to obtain the corrected Polar RR intervals. Six 5-min segments related to different running slopes were considered for each subject. RESULTS: The correlation between corrected V800 RR intervals and Holter RR intervals was very high (r = 0.99, p  0.05) and were well correlated (r ≥ 0.96, p < 0.001). CONCLUSION: Narrow limits of agreement, high correlations and small effect size suggest that the Polar V800 is a valid tool for the analysis of heart rate variability in athletes while running high endurance events such as marathon, trail, and ultra-trail races. KEYWORDS: HRV; Open field running conditions; Polar V800 heart rate monitor; Validatio

Training-induced gene expression plasticity in cardiac function and neural regulation for ultra-trail runners

This study aims to assess the gene regulatory response from a group of 16 athletes and to observe the plasticity induced by their training regime on the gene expression response after their participation in an 82km race. Blood samples for differential gene expression (DGE) were collected before and after this effort from two groups of runners with different training regimes: elite and active. Analyses only focused on genes annotated as related to cardiac function (CF) and neural regulation (NR) from the KEGG PATHWAY Database. Thus, 13 pathways were considered accounting for a total of 629 genes. Training regime modulated the response to exercise based on a list of 18 ranked genes with significant DGE for elite runners while remained statistically insignificant for active athletes. UQCR11, COX7C and COX4I1 genes, related to mitochondrial respiratory chain, were down-regulated which may indicate mitochondrial function impairment in cardiac muscle. Increased expression levels were obtained for PIK3R2, PLCG2, IRAK3 genes from the positive signaling cascades of neurotrophins pathway, which may reveal an improved heart rate control thanks to a better cardiac sympathetic innervation.Postprint (author's final draft

Cardiac damage biomarkers and heart rate variability following a 118-km mountain race: relationship with performance and recovery

This study aimed to assess the release of cardiac damage biomarkers jointly with cardiac autonomic modulation after a mountain ultramarathon. Such knowledge and the possible relationship of these markers with race time is of primary interest to establish possible recommendations upon athletes’ recovery and return to training following these competitions. Forty six athletes enrolled in the Penyagolosa Trails CSP115 race (118 km and a total positive elevation of 5439 m) took part in the study. N-terminal pro-brain natriuretic peptide (NT-proBNP) and high-sensitive cardiac troponin T (hs-TNT) concentrations as well as linear and nonlinear heart rate variability (HRV) were evaluated before and after the race. NT-proBNP and hs-TNT significantly increased post-race; fifty percent of the finishers surpassed the Upper Reference Limit (URL) for hs-TNT while 87% exceeded the URL for NT-proBNP. Overall and vagally-mediated HRV were diminished and cardiac autonomic modulation became less complex and more predictable following the race. More pronounced vagal modulation decreases were associated with higher levels of postexertional NT-proBNP. Moreover, rise in hs-TNT and NT-proBNP was greater among faster runners, while pre-race overall and vagally-mediated HRV were correlated with finishing time. Participation in a 118-km ultratrail induces an acute release of cardiac damage biomarkers and a large alteration of cardiac autonomic modulation. Furthermore, faster runners were those who exhibited a greater rise in those cardiac damage biomarkers. In light of these findings, an appropriate recovery period after ultraendurance races appears prudent and particularly important among better performing athletes. At the same time, HRV analysis is shown as a promising tool to assess athletes’ readiness to perform at their maximum level in an ultraendurance race

Central and peripheral fatigue in recreational trail runners: A pilot study

[Abstract]: Background: Understanding fatigue mechanisms is crucial for exercise performance. However, scientific evidence on non-invasive methods for assessing fatigue in trail running competitions is scarce, especially when vertical kilometer trail running races (VK) are considered. The main purpose of this study was to assess the autonomic nervous system (ANS) activity (i.e., central fatigue) and the state of muscle activation (i.e., peripheral fatigue) before and after a VK competition. Methods: A cross-sectional pilot study was performed. After applying inclusion/exclusion criteria, 8 recreational male trail runners (31.63 7.21 yrs, 1.75 m 0.05 m, 70.38 5.41 kg, BMI: 22.88 0.48, running experience: 8.0 3.63 yrs, weekly training volume: 58.75 10.35 km) volunteered to participate and were assessed for both central (i.e., via heart rate variability, HRV) and peripheral (via tensiomyography, TMG) fatigue before and after a VK race. Results: After the VK, resting heart rate, RMSSD (p = 0.01 for both) and SDNN significantly decreased (p = 0.02), while the stress score and the sympathetic-parasympathetic ratio increased (p = 0.01 and p = 0.02, respectively). The TMG analyses suggest that runners already suffered peripheral fatigue before the VK and that 20–30 min are enough for muscular recovery after the race. In summary, our data suggest that participants experienced a pre-competition fatigue status. Further longitudinal studies are necessary to investigate the mechanisms underlying fatigue during trail running races, while training periodization and tapering strategies could play a key role for minimizing pre-competition fatigue status

ACUTE EFFECTS OF LONG DISTANCE RUNNING ON C-REACTIVE PROTEIN AND ARTERIAL STIFFNESS

Abstract Central arterial stiffness, indicated by pulse wave velocity (PWV), is increased during the hour post ultramarathon (ULT), but it\u27s currently unknown if PWV remains elevated 24 hours after ULT or marathon (MAR). PURPOSE: To determine the effects of ULT and MAR on C-reactive protein (CRP), aortic blood pressure (BP), aortic augmentation index (AIx), PWV, and LF:HF ratio. We hypothesized that CRP, AIx, PWV and LF:HF ratio would be elevated 24 hours post-race. Our secondary hypothesis was that changes in PWV would be inversely correlated to the percentage of moderate activity (3-6 METs) during competition. METHODS: Applanation tonometry was used to measure aortic BP, AIx and PWV in 12 endurance athletes (36±2 yr) approximately 18 hours before and 24 hours after an ULT or MAR. Plasma CRP, resting BP, and LF:HF ratio were also measured. Intensity and pacing were quantified via wrist accelerometry. RESULTS: In relation to baseline vs. 24 hour post-race, respectively, CRP was significantly (pCONCLUSION:CRP was increased 24 hours post-race, while at the same time aortic BP was decreased. Reduced AIx may contribute to the acute exercise-induced hypotension in long-distance runners 24 hours post-race. Results from our secondary hypothesis indicated that long-distance runners may have better PWV outcomes by pacing with intermittent moderate intensity (i.e., jogging or walking)

Reducing Muscular Fatigue in Trail Running - Mechanisms and Strategies

The aim of this thesis was to analyse strategies to reduce muscular fatigue in trail running and potentially draw conclusions on the underlying mechanisms. Trail running is a new and upcoming sport that induces a combination of fatigue and muscle damage in the main locomotor muscles. To obtain conclusive evidence on the effect of intervention studies a preliminary descriptive study was undertaken to characterise typical fatigue and damage. Subsequently a model was developed and validated that would allow the investigation of interventions in an applied field setting. A popular current strategy in trail running is the use of compression garments; therefore the effect of these on performance was studied as an intervention. Furthermore, prior heating is anecdotally considered beneficial and recent research has suggested a potential mechanism to link this with reduced muscle damage. Therefore a controlled laboratory study was conducted, examining the effects of passive heating on functional consequences of downhill running in an untrained population. In synopsis, the research conducted for this thesis provides descriptive evidence and a validated terrain model to further investigate fatigue reduction strategies in trail running. Additionally it adds to the current literature in disproving a positive effect of compression garments on performance and demonstrating the functional link between heating and eccentric-induced muscle damage reduction

Physiological Changes during an Ultramarathon in Extreme Cold: The Yukon Arctic Ultra, the Longest and Coldest Ultramarathon

An increasing number of people engage in endurance exercise, however, current literature lacks information regarding changes during ultramarathons of very long distances at very low intensity, i.e., walking instead of running. In addition, adverse conditions, like very cold climate, have not been investigated in such settings. Furthermore, the physiological processes linking functions like energy expenditure, metabolism, stress, and resilience, are still not well understood or lack investigation all together. The Yukon Arctic Ultra (YAU) has been coined to be the longest and the coldest ultramarathon in the world, as it challenges athletes to complete the very long distance of 690 km under the extremely cold climate conditions of North-Canadian subarctic winter. YAU athletes face the challenges of long-term endurance exercise in a very cold climate and under diminished resting conditions. Thusly, the YAU served as a model to investigate physiological changes among healthy athletes during an ultra-long endurance exercise in extremely cold climate. The presented investigation revealed considerable increases in energy expenditure among the athletes, of up to more than four times resting metabolic rate, along with a marked energy deficit, changes in body composition with reductions in fat mass while fat free mass could mostly be retained, possibly to the exercise- and cold-induced release of myokines like irisin and follistatin. Furthermore, analysis of vegetative control expressed through heart rate variability, as well as of mood through psychometric measurements, revealed that the more successful athletes, who would eventually be able to finish the race, showed better adaptation to the race demands, with less depression, anxiety and anger, but greater vigor and higher alertness. They also exhibited a faster restoration of vagal predominance during the race with a better ability to relax and restore, leading to less sleepiness and greater vigilance compared to the non-finishing athletes. Resilience, as the ability to cope with stressful events, appears to be a key element during such a race and neuropeptide Y has been discussed as a mediator in resilience reactions. The analyses revealed that during this race, neuropeptide Y was associated with less confusion and better quality of recovery among the finisher group and that overall neuropeptide Y was increasingly released among the athletes compared to the less challenged control group. Another influence was the factor sex, indicating that the female athletes were not only as successful as the male participants to complete the whole race, but that women completed an overall greater distance, when accounting for all covered distances. Women, with a moving speed of 3.7 km/h, were considerably slower than men at 4.6 km/h, which may have saved energy stores and allowed them to predominantly use fat as a long-term energy source. In addition, it was shown that ultra-long endurance exercise may lead to shedding of endothelial glycocalyx elements and that these elements appear to be differently susceptible to that shedding. Sex, age, and covered distance all appeared to have an influence on the observed changes. The analyses of physiological changes during the Yukon Arctic Ultra have revealed a multitude of endurance- and cold-exposure-related alterations. This ultramarathon has thusly proven to be an outstanding model to study human adaptation capabilities to extreme environments under real-life field conditions that could otherwise not be replicated in a laboratory setting

Endurance races effects in non-elite runners by clinical biomarkers and bioimpedance measurements

Participation in marathons and ultra-endurance races is growing every day, but it is worrisome that these types of races are becoming mass events, where many runners are not sufficiently prepared. For example, in the 2017 Barcelona marathon there were 19.740 runners, whereas in the 2007 marathon there were 7.430_ runners (Zurich Barcelona Marathon). In the age of social media everyone wants to put his/her photo and comment on instagram, facebook, twitter, etc., about the achievement reached, without caríng if his/her healt.h has been compromised. A marathon or longer distance races, require significant exertions and result in impact to our bodies and bring short and long-term consequences for our health. Never befare has running been so fashionable, but to what extent is it done in a healthy manner? The motivation and merit of this thesis líes in the fact of finding the impact of a 42km run on our body and evaluate the risk of muscle and cardiac damage, inflammation and infection, and renal impairment. The results embodied in the different research articles of this thesís, due to the small number of runners are subjective and show a tendency to be validated in other studies with more athletes. More than 80 non-elite runners were studied during 4 years (from 2016 to 2019). The changes evaluated in pre-race conditions {baseline), at the end, and 48h post-race were through blood and saliva biomarkers. Additionally, other variables were assessed before the race, like nutrition balance and sorne specific supplement intake, and it was proved how the body weight, recovery time, and amount of training done can directly affect the runner's performance and health. The highest elevations in biomarkers associated to muscle damage (CK), inflammation (CRP), and cardiovascular health (Hs-TnT, NT-proBNP, ST2) were seen in the runners with the worse performance time and less training hours before-race. Also, the marathon provoked changes in the salivary immunity and increased the risk of developing a respiratory tract infection. In addition, supplementation actions like polysaccharide-based ones, positively affected on the immune response initiated during a 42 km effort. By BIVA methodogly, a correlation can be made with a displacement ofthe vector impedance at 24 h and 48 h post-race on the tolerance ellipses of a European Caucasian reference population with biomarkers of renal damage. Transient values of acute kidney injury (AKI) stage 1, more related to inflammatory factors rather than muscle damage, were found in many marathoners which recovered mostly 48 h post-race. · Regarding diet, a correct mono- and poly-unsaturated fatty acid, potassium, and magnesium intake befare the marathon influenced better performance and better cardiovascular health. But, what are the negative long-term effects of these acute changes in clinical biomarkers and bioimpedance measurements after 42 km? How does it affect an inadequate diet and preparation? This thesis is based on five original publications, three accepted and two under review, separated in three chapters ordered from 2 to 4, starting with cardidVascular biomarkers, immunity, and supplements. In Appendix 1, renal function and bioimpedance vector displacement, and in Appendix 2, diet effects on performance and cardiac health. An introduction in Chapter 1, describes the rationale of the published work and its place within the whole topic of this thesis. As an elite runner for many years and already a veteran, this thesis is my "grain of sand" in the fasciriating world of metabolic responses while running.La participació en maratons i curses d'ultra resistència creix cada dia, però és preocupant que aquest tipus de curses es converteixin en esdeveniments massius, on molts corredors no estan prou preparats. Per exemple, a la marató Barcelona del 2017 hi havía 19.740 corredors, mentre que a la marató del 2007 hi havia 7.430 corredors (Zurich Barcelona Marató). En l'era de les xarxes socials, tots volen posar la seva foto i comentar a lnstagram, Facebook, Twitter, etc., sobre l'assoliment aconseguit, independentment de si la seva salut s'ha vist compromesa. Una marató o cursa de llarga distància, requereix esforços sígnificatius i té un impacte en el nostre cos amb unes conseqüències a curt i llarg termini pera la nostra salut. Mai abans havia¿ estat tan de moda córrer, però fins a quin punt es fa de manera saludable? La motivació i el mèrit d'aquesta tesi rau en el fet de veure !'impacte d'una carrera de 42 km en el nostre cos i avaluar el risc de dany muscular i cardíac, d'inflamació i infecció, i d'insuficiència renal. Els resultats exposats en els diferents articles d'investigació d'aquesta tesi, a causa del petit nombre de corredors, són subjectius i mostren una tendència a ser validats en altres estudis amb més atletes. Es van estudiar més de 80 corredors no elit durant 4 anys (del 2016 al 2019). Els canvis avaluats en les condicions prèvies a la cursa (estat basal), al final i 48 hores després de la cursa, es van realitzar a través de biomarcadors en sang i saliva. A més a més, es van avaluar altres variables abans de la cursa, corn l'equilibri nutricional i una suplementació específica, i es va demostrar com el pes corporal, el temps de recuperació i la quantitat d'entrenament realitzat poden afectar directament el rendiment i la salut del corredor. Les elevacions més altes en els biomarcadors associats amb el dany muscular (CK), la inflamació (CRP) i la salut cardiovascular (Hs-TnT, NT-proBNP, ST2) es van observar en els corredors amb pitjor rendiment en carrera i amb menys hores d'entrenament abans de la cursa. A més, la marató va provocar canvis en la immunitat salival i va augmentar el risc de desenvolupar una infecció del tracte respiratori. Així mateix, les accions de suplementació com les basades en polisacàrids van afectar positivament la resposta immune iniciada durant l'esforç de córrer 42 km. Segons el mètode BIVA, es pot fer una correlació del desplaçament del vector impedància a les 24 h i 48 h després de la carrera sobre les el·lipses de tolerància d'una població de referencia caucàsica europea, amb els biomarcadors de dany renal. Els valors transitoris de la lesió renal aguda (AKI) tipus 1, més relacionats amb factors inflamatoris que amb el dany muscular, es van trobar en molts maratonians que van recuperar a les 48 h després de la cursa. Pel que fa a la dieta, una correcta ingesta d'àcids grassos monoinsaturats i poliinsaturats, potasi i magnesi abans de la marató va influir en un millar rendiment i una millar salut cardiovascular. Però quins són els efectes negatius a llarg termini d'aquests canvis aguts en els bíomarcadors clínics i en les mesures de bioimpedància després de 42 km? Com afecta una dieta i una preparació inadequades? Aquesta tesi es basa en cinc publicacions originals, 3 acceptades i dos en revisió, separades en tres capítols ordenats del 2 al 4, començant amb biomarcadors cardiovasculars, infecció, immunitat i suplementació. En l'Annex 1, la funció renal i el desplaçament del vector de bioimpedància, i l'Annex 2, els efectes de la dieta sobre el rendiment í la salut cardíaca. Una introducció al Capital 1 descriu la justificació del treball publicat i el seu lloc dins el tema general d'aquesta tesi. Com a corredora d'elit durant molts anys i ja veterana, aquesta tesi és el meu "gra de sorra" en el fascinant món de les respostes metabòliques mentre correm.La participación en maratones y carreras de ultra resistencia crece cada día, pero es preocupante que este tipo de carreras se conviertan en eventos masivos, donde muchos corredores no están lo suficientemente preparados. Por ejemplo, en la maratón Barcelona de 2017 había 19.740 corredores, mientras que en la maratón de 2007 había 7.430 corredores (Zurich Barcelona Marathon). En la era de las redes sociales, todos quieren subir su foto y comentar en Instagram, Facebook, Twitter, etc., sobre el logro alcanzado, sin importar si su salud se ha visto comprometida. Una maratón o carrera de larga distancia, requiere esfuerzos significativos y tiene un impacto en nuestro cuerpo con unas consecuencias a corto y largo plazo para nuestra salud. Nunca antes había estado tan de moda correr, pero ¿hasta qué punto se hace de manera saludable? La motivación y el mérito de esta tesis radica en el hecho de ver el impacto de una carrera de 42 km en nuestro cuerpo y evaluar el riesgo de daño muscular, daño cardíaco, inflamación, cambios inmunológicos, infección, e insuficiencia renal. Un total de 234 corredores no elite se estudiaron durante 4 años (del 2016 al 2019). Los artículos presentados en esta tesis se basan en los corredores que participaron en la maratón del 2016. En el artículo “The Dynamics of Cardiovascular Biomarkers in non-Elite Marathon Runners” se analizaron 79 corredores, en el de “Salivary immunity and lower respiratory tract infections in non-elite marathon runners” se analizaron 47 corredores y en el de “Effects of a polysaccharide-based multiingredient supplement on salivary immunity in non-elite marathon runners” se analizaron 41 corredores. Los cambios evaluados en las condiciones previas a la carrera (estado basal), al final y 48 horas después de la carrera, se realizaron a través de biomarcadores de sangre y saliva. Además, se evaluaron otras variables antes de la carrera, como el equilibrio nutricional y una suplementación específica, y se demostró como el peso corporal, el tiempo de recuperación y la cantidad de entrenamiento realizado pueden afectar directamente el rendimiento y la salud del corredor. Las elevaciones más altas en los biomarcadores asociados con el daño muscular (CK), la inflamación (CRP) y la salud cardiovascular (Hs-TnT, NT-proBNP, ST2) se observaron en los corredores con peor rendimiento en carrera y con menos horas de entrenamiento antes de la misma. Además, la maratón provocó cambios en la inmunidad salival y aumentó el riesgo de desarrollar una infección del tracto respiratorio. A su vez, las acciones de suplementación como las basadas en polisacáridos afectaron positivamente la respuesta inmune iniciada durante el esfuerzo de correr 42 km. Según el método BIVA, se puede hacer una correlación del desplazamiento del vector impedancia a las 24 h y 48 h después de la carrera sobre las elipses de tolerancia de una población de referencia caucásica europea, con los biomarcadores de daño renal. Los valores transitorios de la lesión renal aguda (AKI) tipo 1, más relacionados con factores inflamatorios que con el daño muscular, se encontraron en muchos maratonianos que recuperaron a las 48 h después de la carrera. Con respecto a la dieta, una correcta ingesta de ácidos grasos monoinsaturados y poliinsaturados, potasio y magnesio antes de la maratón influyó en un mejor rendimiento y una mejor salud cardiovascular. ¿Pero cuáles son los efectos negativos a largo plazo de estos cambios agudos en los biomarcadores clínicos y las mediciones de bioimpedancia después de 42 km? ¿Cómo afecta una dieta y una preparación inadecuadas? Esta tesis se basa en cinco publicaciones originales, tres aceptadas y dos en revisión, separadas en tres capítulos ordenados del 2 al 4, comenzando con biomarcadores cardiovasculares, infección, inmunidad y suplementación. En el Anexo 2, la función renal y el desplazamiento del vector de bioimpedancia, y en el Anexo 3, los efectos de la dieta sobre el rendimiento y la salud cardíaca. Una introducción en el Capítulo 1 describe la justificación del trabajo publicado y su lugar dentro del tema general de esta tesis. Como corredora de élite durante muchos años y ya veterana, esta tesis es mi "grano de arena" en el fascinante mundo de las respuestas metabólicas que hace nuestro cuerpo mientras corremo

Acute effects of long-distance races on heart rate variability and arterial stiffness: A systematic review and meta-analysis

This study systematically reviewed and quantified the effects of running a long-distance race (LDR) on heart rate variability (HRV) and arterial stiffness (AS). All types of races of a distance equal to or greater than a marathon (=42.2 km) were included. A total of 2, 220 articles were identified, 52 were included in the qualitative analysis, and 48 were meta-analysed. The standardised mean difference pre- and post-race of various time-domain and frequency-domain indices of HRV, mean arterial blood pressure (MAP), systolic blood pressure (SBP), diastolic blood pressure (DBP) and carotid-femoral pulse wave velocity (cfPWV) was calculated. Regarding HRV, there was a significant decrease in most of the variables considered as markers of parasympathetic activity, indicating a shift of autonomic balance towards a reduced vagal tone. Regarding vascular variables, there was a significant drop in blood pressure and reduced AS. In conclusion, running an LDR seems to have a considerable acute effect on the autonomic nervous system, haemodynamics, and vascular properties. The observed effects could be categorised within the expected acute responses to long-lasting, strenuous exercise. © 2021 Informa UK Limited, trading as Taylor & Francis Group