Blood volume expansion following supramaximal exercise : occurrence and contribution to maximal oxygen uptake

Previously published research using various types of exercise has shown that central hemodynamic factors such as blood volume (BV) and maximal cardiac output (Qmax) are of large importance in the mediation of improvements in VO2max. Whether this is true for adaptations induced by sprint-interval training (SIT) is unclear. Three experimental studies were carried out investigating the occurrence and contribution of hypervolemia to SIT-induced improvements in VO2max. Forty-eight study participants performed the interventions. Significant increases in BV and Qmax were observed after the 6-week training interventions in conjunction with the expected increases in VO2max (Paper Ⅰ and Ⅱ). The hypervolemic response was shown not only to be associated with the increase in VO2max but also to be the primary mediator of it, as demonstrated by the elimination of the exercise-induced increases in VO2max when BV was normalized to pre-intervention levels by phlebotomy. This demonstrates that central adaptations are paramount for the SIT-induced increase in VO2max. In addition, systemic oxygen extraction increased as a consequence of decreased venous oxygen content during maximal exercise (Paper Ⅱ). This suggests that both peripheral and central factors are responsible for the adaptations in VO2max observed with SIT and refutes previous theories proposing that the increase in VO2max was mediated primarily by peripheral adaptations. Metabolic and intravascular perturbation has been proposed as an important stimuli for exercise adaptation. Since SIT is one of the most intense forms of exercise available the immediate effects after SIT are interesting in order to understand how such small amounts of exercise can lead to cardiovascular adaptations usually associated with more prolonged types of exercise. Acute effects of one session of SIT caused pronounced disturbance of the intravascular milieu and perturbations of the muscle metabolism. The variable that correlated best with changes in plasma and muscle volume was glucose-6-phosphate (Paper Ⅲ). Similarly, plasma osmolality and plasma concentration of arginine and citrulline was shown to be the best predictors of improvements in VO2max after a training intervention of 6-weeks (Paper Ⅳ). Overall, the present work demonstrates that brief supramaximal exercise leads to improvements in VO2max and that these improvements are mediated mainly by central adaptations. Peripheral adaptations occur concurrently but cannot alone explain the improvements in VO2max, as previously hypothesized. The data presented show that both central and peripheral adaptations are involved in the improvement of VO2max after an SIT intervention

Acta kinesiologiae Universitatis Tartuensis. 16(Supplement)

http://www.ester.ee/record=b1227224*es

The effect of heat stress, dehydration and exercise on global left ventricular function and mechanics in healthy humans

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.This thesis examined the effect of heat stress, dehydration and exercise on global left ventricular (LV) function and LV twist, untwisting and strain (LV mechanics) in healthy individuals. The primary aim was to identify whether the different haemodynamics induced by heat stress, dehydration and exercise would be associated with alterations in systolic and diastolic LV mechanics as assessed by two-dimensional speckle tracking echocardiography. Study one showed that enhanced systolic and diastolic LV mechanics during progressively increasing heat stress at rest likely compensate in part for a lower venous return, resulting in a maintained stroke volume (SV). In contrast, heat stress during knee-extensor exercise did not significantly increase LV twist, suggesting that exercise attenuates the increase in LV mechanics seen during passive heat stress. Study two revealed that dehydration enhances systolic LV mechanics whilst diastolic mechanics remain unaltered at rest, despite pronounced reductions in preload. The maintenance of systolic and diastolic LV mechanics with dehydration during knee-extensor exercise further suggests that the large decline in SV with dehydration and hyperthermia is caused by peripheral cardiovascular factors and not impaired LV mechanics. During both, heat stress and dehydration, enhanced systolic mechanics were achieved solely by increases in basal rotation. In contrast, the third study demonstrated that when individuals are normothermic and euhydrated, systolic and diastolic basal and apical mechanics increase significantly during incremental exercise to approximately 50% peak power. The subsequent plateau suggests that LV mechanics reach their peak at sub-maximal exercise intensities. Together, the present findings emphasise the importance of acute adjustments in both, basal and apical LV mechanics, during periods of increased cardiovascular demand

Exercise & cardiopulmonary physiology in rheumatoid arthritis

A thesis submitted in partial fulfilment of the requirements of the University of Wolverhampton for the degree of Doctor of Philosophy.Background: Rheumatoid arthritis (RA) individuals are at greater morbidity and mortality risk from developing cardiac and pulmonary disorders than the general population, primarily due to a sedentary lifestyle. Aims: This project aimed to (1) obtain information on the rheumatic and musculoskeletal disease (RMD) patents’ achieved/preferred exercise principles and awareness, (2) investigate the need to implement and safety, as depicted when a verification phase is added at the cardiopulmonary exercise tolerance test (CPET) in RA, to confirm the attainment of maximal effort, (3) evaluate potential differences between RA individuals and non-RA controls regarding the cardiopulmonary physiology and its association with the cardiorespiratory fitness (CRF) level and (4) assess possible cardiopulmonary changes following a supervised three-month aerobic high-intensity interval training (HIIT) regimen and examine its adherence in RA. Methods: A total of 298 individuals were recruited. A newly developed questionnaire in RMDs explored qualitative data about exercise. CRF was evaluated through a combined CPET with verification phase protocol. CPET was analysed for its sensitivity, specificity, positive and negative likelihood ratios (LH+/LH-), and diagnostic odds ratio (DOR). The verifications’ phase safety was examined through CPET's absolute and relative contraindications during monitoring and patient’s acceptability. Cardiopulmonary physiology was investigated via both echocardiography and complete pulmonary function tests (PFTs). To estimate the disease activity score (DAS28) ‐ C‐reactive protein (CRP) was used in people living with RA. Results: Study 1: The most preferred exercise routine characterised by a frequency of “2-3 times per week”, moderate intensity, lasting “about an hour’’, with swimming being the best- suggested modality. In Study 2, a combined CPET with a verification phase protocol presented superior diagnostic accuracy and was free from safety issues for both people with RA and non-RA controls. In Study 3, in the absence of any overt cardiac and/or pulmonary disease, RA individuals presented with an eccentric cardiac remodelling and lung hyperinflation pattern compared to non-RA controls; CRF was associated (p<0.05) with left ventricular (LV) compliance and pulmonary function indices in both groups. Study 4: The HIIT programme revealed significant (p<0.05) improvements in pulmonary function, CRF, and reduced DAS28, while individuals adhered overall moderately to this regime. Conclusions: This Thesis concluded that: (1) exercise recommendations are not individualised according to the individuals’ needs and preferences in RMDs, (2) the combined CPET with a verification phase is a safe and necessary methodology to ensure a diagnostically accurate assessment of maximal effort for both people living with RA and non- RA controls, (3) people living with RA may present a parallel eccentric cardiac remodelling with a hyperinflation pattern in the subclinical phase, while CRF levels associate with cardiopulmonary function indices in both groups, and (4) a moderately adhered three-month aerobic HIIT exercise regimen can significantly improve pulmonary function, CRF, and RA's disease state.University of Wolverhampton

Acta kinesiologiae Universitatis Tartuensis. 10

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Aerospace medicine and biology: A continuing bibliography with indexes, supplement 218, April 1981

This bibliography lists 161 reports, articles, and other documents introduced into the NASA scientific and technical information system in March 1981

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

Are ACE I/D and ACTN3 R577X polymorphisms associated with muscle function of young and older men, and frequent fallers?

Angiotensin Converting Enzyme (ACE) IID, and a actinin 3 (AC1N3) R577X polymorphisms have been linked to the strength and power performance of elite athletes and suggested to influence skeletal muscle function in the general popUlation. This research investigated the association of these two candidate gene polymorphisms with the muscle function of young and older men, and the distribution of these genotypes in frequent fallers compared to controls. Muscle function measurements of young and older men included isometric strength, absolute and relative isokinetic strength at high velocity (ratio of torque at 2400 ·s"; torque at 30°·s") and the time course of an evoked twitch. Additionally body composition was measured by skinfold thickness (young men) and DXA scanning (old men) to estimate fat-free mass, an index of muscularity, and fat mass. ACE and AC1N3 genotypes were determined from whole blood samples using polymerase chain reaction, and serum ACE activity using spectrophotometry. The gemtypes of frequent fallers referred to a Falls Clinic were compared to a control group of healthy men. ACE genotype was not associated with any measure of muscle function, including the time course of an evoked twitch or absolute and relative high velocity torque, or body composition in these populations (ANOVA, 0.1

The effect of heat stress, dehydration and exercise on global left ventricular function and mechanics in healthy humans

This thesis examined the effect of heat stress, dehydration and exercise on global left ventricular (LV) function and LV twist, untwisting and strain (LV mechanics) in healthy individuals. The primary aim was to identify whether the different haemodynamics induced by heat stress, dehydration and exercise would be associated with alterations in systolic and diastolic LV mechanics as assessed by two-dimensional speckle tracking echocardiography. Study one showed that enhanced systolic and diastolic LV mechanics during progressively increasing heat stress at rest likely compensate in part for a lower venous return, resulting in a maintained stroke volume (SV). In contrast, heat stress during knee-extensor exercise did not significantly increase LV twist, suggesting that exercise attenuates the increase in LV mechanics seen during passive heat stress. Study two revealed that dehydration enhances systolic LV mechanics whilst diastolic mechanics remain unaltered at rest, despite pronounced reductions in preload. The maintenance of systolic and diastolic LV mechanics with dehydration during knee-extensor exercise further suggests that the large decline in SV with dehydration and hyperthermia is caused by peripheral cardiovascular factors and not impaired LV mechanics. During both, heat stress and dehydration, enhanced systolic mechanics were achieved solely by increases in basal rotation. In contrast, the third study demonstrated that when individuals are normothermic and euhydrated, systolic and diastolic basal and apical mechanics increase significantly during incremental exercise to approximately 50% peak power. The subsequent plateau suggests that LV mechanics reach their peak at sub-maximal exercise intensities. Together, the present findings emphasise the importance of acute adjustments in both, basal and apical LV mechanics, during periods of increased cardiovascular demand.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

The effect of heat stress, dehydration and exercise on global left ventricular function and mechanics in healthy humans

This thesis examined the effect of heat stress, dehydration and exercise on global left ventricular (LV) function and LV twist, untwisting and strain (LV mechanics) in healthy individuals. The primary aim was to identify whether the different haemodynamics induced by heat stress, dehydration and exercise would be associated with alterations in systolic and diastolic LV mechanics as assessed by two-dimensional speckle tracking echocardiography. Study one showed that enhanced systolic and diastolic LV mechanics during progressively increasing heat stress at rest likely compensate in part for a lower venous return, resulting in a maintained stroke volume (SV). In contrast, heat stress during knee-extensor exercise did not significantly increase LV twist, suggesting that exercise attenuates the increase in LV mechanics seen during passive heat stress. Study two revealed that dehydration enhances systolic LV mechanics whilst diastolic mechanics remain unaltered at rest, despite pronounced reductions in preload. The maintenance of systolic and diastolic LV mechanics with dehydration during knee-extensor exercise further suggests that the large decline in SV with dehydration and hyperthermia is caused by peripheral cardiovascular factors and not impaired LV mechanics. During both, heat stress and dehydration, enhanced systolic mechanics were achieved solely by increases in basal rotation. In contrast, the third study demonstrated that when individuals are normothermic and euhydrated, systolic and diastolic basal and apical mechanics increase significantly during incremental exercise to approximately 50% peak power. The subsequent plateau suggests that LV mechanics reach their peak at sub-maximal exercise intensities. Together, the present findings emphasise the importance of acute adjustments in both, basal and apical LV mechanics, during periods of increased cardiovascular demand.EThOS - Electronic Theses Online ServiceGBUnited Kingdo