Introdução: O Teste Ergoespirométrico (TEE) tem mudado profundamente a abordagem da avaliação funcional, relacionando aptidão física e parâmetros fisiológicos ao substrato metabólico subjacente, e fornecendo descritores de capacidade de esforço altamente reprodutíveis. A elaboração de uma fórmula para cálculo do incremento de carga em um TEE incremental do tipo rampa por Wasserman e colaboradores representou um grande auxílio na escolha da intensidade mais adequada para otimizar a qualidade do teste e respeitar a recomendação de tempo de duração do teste (10 ± 2 minutos). Em muitos casos, apenas a estimativa do incremento de potência pela fórmula, baseada em características antropométricas e direcionada a indivíduos saudáveis sedentários, acaba subestimando ou superestimando a real capacidade funcional do indivíduo ou paciente. Características marcantes do estado de saúde (boa aptidão física, atleta, treinados), assim como do estado de doença (insuficiência cardíaca crônica, infarto do miocárdio, doença arterial coronária) interferem diretamente no desempenho e homeostase dos sistemas pulmonar, cardiovascular e músculo-esquelético. Objetivo: Os objetivos desse trabalho foram investigar o comportamento das variáveis ventilatórias e suas correlações nas distintas fases de um protocolo de esforço incremental do tipo rampa, em indivíduos saudáveis e coronariopatas, frente a um TEE e, analisar a concordância entre as medidas reais obtidas pelo TEE e os valores previstos pela equação de Wasserman em ambos os grupos. Além disso, caso ocorressem diferenças entre essas medidas, determinar o quanto afetam as diferenças da rampa de potência aplicada. Métodos: Foram recrutados 28 indivíduos do sexo masculino, sendo 16 coronariopatas, idade média 57 ± 8 anos e 12 saudáveis, idade média 47 ± 4 anos. Ambos grupos realizaram um TEE em cicloergômetro, com protocolo do tipo rampa e intensidade calculada segundo a equação de Wasserman. Todos foram incentivados a alcançar o limite máximo de tolerância ao esforço. Resultados e Conclusão: Basicamente, a fórmula de Wasserman não se aplica de forma adequada para prever a capacidade funcional dos voluntários brasileiros estudados, sejam eles saudáveis ou coronariopatas, e assim não prevê precisamente o incremento de potência (rampa) nos TEE incrementais em cicloergômetro. Quando comparamos saudáveis e coronariopatas, a discordância entre as medidas foi muito mais acentuada na amostra coronariopata. Avaliando as variáveis de transporte de oxigênio em repouso e em esforço submáximo e máximo, pudemos observar que o grupo coronariopata apresentou menores valores de FC,VO2 , potência e (FCrepouso: 57 ± 7bpm para GC e 77 ± 14bpm para GS; VO2 repouso: 209,47 ± 34,10ml/min para GC e 259,69 ± 42,25ml/min para GS; FC(LA): 78 ± 15bpm para GC e 103 ± 13 para GS; (LA): 739,75 ± 128,42ml/min para GC e 943,45 ± 191,68ml/min para GS; FC(pico): 117 ± 17bpm para GC e 164 ± 12bpm para GS; VO2 (pico)real: 1327,2 ± 287,15ml/min para GC e 2110 ± 335,83ml/min para GS). Essa redução pôde ser explicada, parcialmente, pelo uso do agente farmacológico bloqueador. A análise de correlação das variáveis obtidas no TEE demonstrou que o efeito cronotrópico negativo é mais pronunciado em intensidades submáximas de esforço. Nessa amostra de coronariopatas não foi encontrada alterações da bomba ventricular esquerda, avaliada pelo pulso de oxigênio (11,48 ± 2,91 para GC e 12,95 ± 2,59 para GS), nem alterações das medidas de / slope (27,33 ± 3,24 para GC e 26,14 ± 2,77 para GS), sugerindo que somente em graus mais avançados de comprometimento da reserva funcional possa ocorrer redução dos valores desse parâmetro. Analisando o VO2 /W, encontramos uma redução dessa relação no grupo coronariopata (7,82 ± 1,3 para GC e 9,41 ± 0,91 para GS, p=0,0005), que justificaria uma menor capacidade de metabolizar e disponibilizar o O2 na periferia, sugerindo, portanto, que o VO2 /W possa representar, no TEE, um marcador alternativo de redução da reserva cardiovascular em pacientes coronariopatas. / Introduction: The Cardiopulmonary exercise test has profoundly changed the approach to functional assessment, linking physical and physiological parameters underlying the metabolic substrate, and providing descriptors highly reproducible exercise capacity. The development of a formula for calculating the load increase in a incremental ramp type cardiopulmonary exercise test by Wasserman and colleagues has a great help in choosing the most appropriate intensity to optimize the quality of the test and comply with the recommendation of the duration of the test (10 ± 2 minutes). In many cases, only the estimate of the increase of power by the formula, based on antropometric characteristics and target to individuals healthy sedentary, just underestimating or overestimating the actual functional capacity of the individual or patient. Salient features of health status (good physical fitness, athlete, trained) as well as the state of disease (chronic heart failure, myocardial infarction, coronary artery disease) direct affect performance and homeostasis of the pulmonary system, cardiovascular and musculoskeletal. Objective: The objectives of this study were to investigate the behavior ventilatory variables and their correlations in the different stages of a incremental exercise protocol type ramp, in health (HG) and coronary artery disease subjects (CG), in a cardiopulmonary exercise test and, examines the correlation between the actual measurements obtained by cardiopulmonary exercise test and the predicted values by the equation of Wasserman in both groups. Moreover, in case of difference between these measurements, determine how the differences affect the power applied ramp. Methods: We recruited 28 males subjects, 16 coronary artery disease patients, average age 57 ± 8 years and 12 healthy, average age 47 ± 4 years. Both groups performed cardiopulmonary exercise test in a cycle ergometer with ramp protocol type and intensity calculated using the equation of Wasserman. All were encouraged to achieve the maximum effort tolerance. Results and conclusion: Basically, the formula of Wasserman does not apply adequately to predict the functional capacity of Brazilian volunteers studied, whether healthy or coronary artery disease, and does not provide precisely the increase in power (ramp) in cardiopulmonary exercise test incremental cycle ergometer. When comparing health and coronary artery disease, the disagreement between the measurements was much more pronounced in the sample with coronary artery disease. Assessing the variables of oxygen transport at rest and at submaximal and maximal effort, we observed that the coronary disease group had lower heart rate, oxygen uptake, power and ventilation (FCrepouso: 57 ± 7bpm to CG e 77 ± 14bpm to HG; VO2repouso: 209,47 ± 34,10ml/min to CG e 259,69 ± 42,25ml/min to HG; FC(LA): 78 ± 15bpm to CG e 103 ± 13bpm to HG; (LA): 739,75 ± 128,42ml/min to CG e 943,45 ± 191,68ml/min to HG; FC(pico): 117 ± 17bpm to CG e 164 ± 12bpm tp HG; VO2(pico)real: 1327,2 ± 287,15ml/min to CG e 2110 ± 335,83ml/min to HG). This reduction could be partially explained by the use of pharmacological agent blocker. Correlation analysis of variables obtained in the cardiopulmonary exercise test showed that the negative chronotropic effect is more pronounced at submaximal intensities of effort. In this sample of coronary artery disease was not found changes in left ventricular pump, as measured by oxygen pulse (11,48 ± 2,91 to CG e 12,95 ± 2,59 to HG) or changes in measures Ve /VCO2 slope (27,33 ± 3,24 to CG e 26,14 ± 2,77 to HG), suggesting that only in advanced stages of impaired functional reserve may occur reducing the values of this parameter. Analyzing the VO2 /W, we found a reduction of this ratio in coronary disease group (7,82 ± 1,3 to CG e 9,41 ± 0,91 to HG, p=0,0005),, which would justify a lower capacity to metabolize and provide O2 in the periphery, thus suggesting that the VO2/W represent, in TEE, an alternative marker reduction of cardiovascular reserve in coronary artery disease patients.

A high percentage of unrecognized myocardial infarctions (UMIs) seen at delayed-enhanced magnetic resonance imaging (DE-MRI) are not detected by ECG. DE-MRI-detected UMIs are independent predictors of cardiovascular events in patients with coronary artery disease. In an elderly population, subjects with DE-MRI-detected UMIs do not have increased Framingham risk score or increased prevalence of artery stenosis in whole-body MR angiography as patients with recognized myocardial infarctions (RMI). Further investigation on the pathogenesis of DE-MRI-detected UMIs focus on the need to decide the management of these subjects. From the Prospective Investigation of the Vasculature in Uppsala Seniors, 248 subjects underwent cardiac MRI at age 70 and from these, 185 underwent a 5-year follow-up MR. DE-MRI-detected UMIs had lower signal intensity than RMIs probably reflecting different composition of their tissues. Subjects with UMI scar had increased levels of NT-proBNP, a predictor of increased risk of cardiovascular events. After 5 years, UMI scars were in their majority seen on the same location and with the same size, and their prevalence increased. Subjects with an UMI did not differ from subjects without a scar in terms of coronary stenosis assessed by computed tomography angiography or signs of ischemia on exercise test. In conclusion, DE-MRI-detected UMI scars are a frequent finding in an elderly population and its prevalence increases with age. The increased levels of NT-proBNP indicate that subjects with an UMI might have an increased rate of future cardiovascular events but the findings that these scars might have a different contrast distribution volume on MRI and that they are not related to CAD are indicators that they probably have a different etiology from RMIs. The prognosis of DE-MRI detected UMI scars in the general population is still unknown and therefore the clinical management of these individuals is yet to be defined.

No description available.

The purpose of this study was to examine the physiological and psychological responses to linear work rate treadmill and cycle ergometer exercise tests in men and women with chronic obstructive pulmonary disease (COPD). 12 men and 8 women with COPD completed one treadmill and one cycle cardiopulmonary exercise test (CPET) in randomized order. Before and after each CPET, the particpants completed measures of Self-Efficacy (SE), State-Anxiety, and Arousal. No significant differences were found between the physiological responses to cycle and treadmill CPET in either men or women. SE increased significantly as a result of the first test, regardless of exercise modality and sex. State anxiety was significantly reduced after the first test, whereas there was no significant change in arousal state. In conclusion there were no differences between the physiological and psychological responses to treadmill and cycle CPET in men and women with COPD.

Laktatkonzentrationszeitkurven nach akuter körperlicher Belastung und im Stufentest haben sich ebenso wie der Dauerleistungstest in der sportwissenschaftlichen Leistungsdiagnostik etabliert. Beide Verfahren erlauben, die Leistungsfähigkeit von Sportlern einzuschätzen und die Trainingsbelastung optimal entsprechend der Sportdisziplin zu steuern. Der Unterarm-Ischämie-Test dient dazu, Muskelerkrankungen auf der Basis von Laktat- und Ammoniakkonzentration zu differenzieren. Die Laktat-Konzentrations-Zeitkurven nach akuter Belastung, im Stufentest oder im Dauerleistungstest sowie im Unterarm-Ischämietest werden vorwiegend deskriptiv durch Parameter wie die maximale Laktatkonzentration oder Leistung bei bestimmter Laktatkonzentration ausgewertet. Das Ziel der vorliegenden Untersuchung ist, pharmakokinetische Modelle für auf der Laktatkonzentration basierende Tests zu prüfen und deren praktische Relevanz zu diskutieren. Dabei können der akute Belastungstest und der Vorderarm-Ischämietest wegen eines ähnlichen Laktatprofils (Peak-Kurven), der Dauerleistungstest (kumulative Kurven) und der Stufentest (stetig monoton steigende Kurven) getrennt betrachtet werden. Die Routinelaktatprofile von 13 männlichen Freizeitsportlern (Alter: 20-35 Jahre), die sich einem 3 Minuten dauernden akuten ergometrischen Leistungstest unterzogen, wurden zur Modellbildung herangezogen. Der Unterarm-Ischämietest wurde bei acht Patienten im Alter zwischen 20 und 45 Jahren, bei denen bei Aufnahme die Verdachtsdiagnose einer Muskelerkrankung des Glukose- oder Eiweißstoffwechsels bestand, durchgeführt. Wird die Laktatkonzentrationszeitkurve, oder im Ischämietest auch der Ammoniakkonzentrationzeitkurve, als Summe eines Produktions- und Eliminationsvorgangs, dagestellt, lassen sich zusätzliche Informationen gewinnen. Blutlaktatkonzentrationen (Cb(t)) nach akuter ergometrischer Belastung wurden mittels nichtlinearer Regression an das Grundmodell Cb(t)=Co+B*(exp(-Lp*t )-exp(-Le*t)) angepasst, wobei Co der Ruhelaktatkonzentration und B einer Konstanten entsprechen. Die Laktatproduktionsrate (Lp) und Laktateliminationsrate (Le) differenzieren zwischen der Laktatproduktion einerseits und der Laktatelimination andererseits. Der Quotient Lp/P (P=erbrachte Leistung) stellt ein standardisiertes Maß für die Laktatproduktion im Muskel dar. Dagegen charakterisiert der Quotient Le/P die Elimination des Laktats aus dem Blutkompartiment. Über die Beziehung HWZp = ln2/Lp und HWZe = ln2/Le können die entsprechenden Halbwertszeiten berechnet werden. Eine reine Laktatproduktionszeitkurve (Cp(t)) lässt sich über die Beziehung Cp(t) = Cb(t) + Le*( ∫Cb(t)-Co*t) rekonstruieren und zeigt anschaulich den Verlauf der Laktatproduktion. Die Produktionszeitkurve erreicht im Verlauf der Elimination asymptotisch einen Maximalwert (Pm) und kann, identische Verteilungsvolumina des Laktats (Vdl) vorausgesetzt, über die Beziehung Ml = Vdl * Pm Informationen über die insgesamt freigesetzte Laktatmenge (Ml) geben. 19 gesunde Probanden unterzogen sich einem standardisierten Stufentest unter folgenden Bedingungen: Vor Beginn der Bergtour (Meereshöhe, SLa), nach Ankunft auf 1700 m (1700a), nach 10tägigem moderaten Training (Bergwandern zwischen 1700 und 3000m, 6 h pro Tag) auf 1700 m (1700b) sowie nach 4 Wochen (kein spezifisches Training) erneut auf Meereshöhe (SLb). Primäres Ziel der Auswertung war, mit der Potenzfunktion der allgemeinen Form Y(x) = A+ B * X^C den funktionalen Zusammenhang zwischen Laktatkonzentration und Belastung bzw. Herzfrequenz und Belastung zu beschreiben. Neben den modellabhängigen Faktoren (Ordinatenabschnitt, Steigungsfaktor, Exponent) ließen sich durch die AUC(70-280) (Area under the curve 70 bis 280 Watt Leistung) das Ausmaß der Laktatproduktion, die entsprechende mittlere Konzentration (Cm) und durch die Laktatkonzentrationen bei 70 und 280 Watt (LT-70, LT-280) der Laktatanstieg charakterisieren. Der Dauerleistungstest hat sich neben dem akuten ergometrischen Belastungstest in der sportmedizinischen Leistungsdiagnostik als Methode etabliert. Bisher konzentrierte sich die Auswertung auf die maximalen Blutlaktatkonzentrationen im steady state. Die Autoren schlagen verschiedene Modelle vor, sowohl empirische als auch mechanistische, um die Laktatkonzentrationszeitkurve im Dauerleistungstest zu beschreiben. Neben der maximalen Konzentration können nach Berechnung der Modellkurven durch nichtlineare Regression Konzentrationen zu definierten Bedingungen (z. B. LT20 = Laktat nach 20 Minuten) oder die Steigung der Kurve beurteilt werden. Darüber hinaus lässt sich die AUC (Area under the curve) als Ausmaß für die Laktatbildung während des Dauerleistungstests mit der Trapezregel bestimmen. Zusammenfassend zeigen die Untersuchungen, dass in allen Verfahren der Laktatdiagnostik, dem akuten Belastungstest, der Standardergometrie, dem Laktatischämietest und dem Dauerleistungstest, signifikante und praktikable pharmakokinetische Modelle berechnet werden können. Sie erlauben es, die Ergebnisse mittels Modellparametern zu quantifizieren und zu vergleichen. / Lactate concentration versus time curves following acute physical exercise, the standard exercise test using increasing levels of work load and the steady state exercise test have been established methods to characterise the fitness of athletes and to control training intensity. The ischemic forearm exercise test (IFET) is used to detect metabolic disorders of muscles based on lactate and ammonia concentration during exercise under ischemia. Lactate concentration curves following acute exercise, standard ergometries and steady state tests as well as IFET are generally analysed descriptively, i. e. maximum lactate concentrations or work load with regard to defined lactate concentrations are used. The primary objective of this study was to assess pharmacokinetic models for lactate in exercise tests and to discuss the relevance in sports science. For practical purpose, the models used in acute and IFET (asymmetric peak curves), the steady state exercise test (cumulative curves) and standard exercise tests (continuously increasing function) are dealt with separately. Routine lactate profiles of 13 male nonprofessional athletes (age: 20-35) years who underwent an acute ergometry lasting 3 minutes were used to assess different pharmacokinetic models. An IFET was performed in 8 patients (Age: 20-45 years) supposed to have disorders of glucose metabolism or lack of myoadenylate deaminase. Lactate concentration versus time curves were fitted by means of non-linear regression to different kinetic models. The modified basic curve Cb(t)=Co+B*(exp(-Lp*t )-exp(-Le*t)), where Cb denotes the baseline concentration, B a constant, Le denotes the lactate elimination constant and Lp the “absorption or production” constant, yielded remarkable nonlinear regression results in for both test settings. Lactate concentration versus time curves in acute exercise tests are mostly assessed descriptively by means of parameters such as maximum concentration or workload with regard to specified lactate levels. Additional diagnostic information can be obtained, if production and elimination processes of the concentration versus time curve are separated. Production rate (Lp) and elimination rate (Le) of lactate are to define the shape of the curve. The ratio Lp/P (P=performance, work load), where Lp denotes the workload of the ergometer, can be considered as a standardized criterion of lactate production in the muscle. On the contrary, the ratio Le/P characterizes the elimination process from the vascular compartment. The corresponding half-lives [Tp, Te] are obtained using the relations Tp = ln2/Lp and Te = ln2/Le. The absolute lactate production versus time curve [Cp(t)] is given by the following equation: Cp(t) = Cb(t) + Le*( ∫Cb(t)-Co*t). The production versus time curve reaches a maximum value (Pm) after termination of the elimination process. If lactate has identical volumes of distribution (Vdl), Pm characterizes the total amount of lactate production (Ml) due to the relation Ml = Vdl*Pm. Nineteen healthy volunteers were exposed to a standardized exercise test at sea level (SLa), at an altitude of 1700 m before (1700a) and after a moderate 10 day mountain training (1700b), with a final control four weeks later at sea level (SLb). Vital signs, blood lactate and arterial oxygen saturation were determined prior, during or after the exercise test. The primary aim of the study was to fit the power function Y(X) = A+ B * X^C as a model for lactate versus workload and heart rate versus workload data. Apart from model characteristics (intercept, slope, exponent) the extent of lactate production could be estimated by the model independent characteristic AUC(70-280) (Area under the curve between 70 and 280 Watt) and the corresponding average concentration (Cm). The degree of lactate increase was characterized by means of the lactate concentration at 70 and 280 Watt (LT-70, LT-280), respectively. Apart from the standard and acute exercise test the steady state exercise test has gained increasing relevance in practice of sports medicine. So far, lactate curves of steady state tests were characterised by means of maximum. The author suggests several models, both empirical and mechanistic models, in order to fit lactate concentration versus time curves of the steady state ergometry. In addition to the maximum lactate concentration fitted nonlinear regression curves allow to assess the concentrations at defined conditions (e.g. LT20=lactate after 20 minutes of steady state workload, EC50 of the Emax model) or the slope of the curve. Moreover, the AUC(0-tx) – a measure for the extent of lactate production – can be calculated using the trapezoidal rule. In conclusion, in all lactate based tests, acute and standard ergometry, ischemic forearm test and steady state exercise test, concentration versus time data were fitted suitable pharmacokinetic models which allow to quantify and compare the results.

Diss. (sammanfattning) Linköping : Linköpings universitet, 2008. / Härtill 4 uppsatser.

Thesis (Ph. D.)--University of Missouri--Columbia, 1998. / Typescript. Vita. Includes bibliographical references (leaves : 103-112). Also available on the Internet.

Thesis--University of Oklahoma. / Bibliography: leaves 94-96.

Thesis (Ph. D.)--Helsinky Univ. of Technology, 2001. / Title from title screen (viewed Oct. 14, 2005). Includes bibliographical references.

Thesis (D. Sc. P.T.)--University of Alabama at Birmingham, 2007. / Title from first page of PDF file (viewed Oct. 30, 2007). Includes bibliographical references (p. 18-20).