Chronic Effects of Different Intensities of Interval Training on Hemodynamic, Autonomic and Cardiorespiratory Variables of Physically Active Elderly People.

Interval training (IT) is a very efficient method. We aimed to verify the chronic effects of IT with different intensities on hemodynamic, autonomic and cardiorespiratory variables in the elderly. Twenty-four physically active elderly men participated in the study and were randomized into three groups: Training Group A (TGA, n = 8), Training Group B (TGB, n = 8) and control group (CG, n = 8). The TGA and TGB groups performed 32 sessions (48 h interval). TGA presented 4 min (55 to 60% of HRmax) and 1 min (70 to 75% of HRmax). The TGB training groups performed the same protocol, but performed 4 min at 45 to 50% HRmax and 1 min at 60 to 65% HRmax. Both training groups performed each set six times, totaling 30 min per session. Assessments were performed pre (baseline) after the 16th and 32nd intervention session. The CG performed only assessments. Hemodynamic, autonomic and cardiorespiratory (estimated VO2max) variables were evaluated. There were no significant differences between protocols and times (p > 0.05). However, the effect size and percentage delta indicated positive clinical outcomes, indicating favorable responses of IT. IT may be a strategy to improve hemodynamic, autonomic and cardiorespiratory behavior in healthy elderly people.

Importancia del VO2máx y la capacidad de recuperación de los futbolistas

El consumo máximo de oxígeno se considera un indicador directamente relacionado con la resistencia aeróbica, por lo que dicha capacidad se hace determinante en el rendimiento del futbolista. Conocer los criterios teóricos nacionales que sustentaron la importancia del VO2máx en la capacidad de recuperación en el fútbol constituyó un paso previo hacia conformar estrategias prospectivas de intervención directa para la toma de decisiones. En tal sentido, se planteó como objetivo de la investigación determinar, por consulta de especialistas, los criterios existentes de la importancia del VO2máx en la capacidad de recuperación de los futbolistas. La investigación fue descriptiva-correlacional de orientación exploratoria; se encuestaron a 13 especialistas que emitieron criterios sobre cinco indicadores. La importancia de la resistencia aeróbica en el entrenamiento del fútbol obtuvo un puntaje de (X4.62) y en relación al resto de las capacidades físicas aplicadas al fútbol un (X3.23); la importancia del VO2máx en el proceso de dirección un (X4.46); la correlación entre VO2máx y la recuperación un (X4.54) y la necesidad de perfeccionar la resistencia aeróbica en el fútbol ecuatoriano un (X4). El índice de concordancia entre especialistas obtuvo un nivel aceptable (w=0.527). Todos los indicadores de análisis obtuvieron una cualificación entre alta y muy alta, por lo que la investigación resaltó la importancia teórica brindada por los especialistas sobre el consumo máximo de oxígeno como indicador directamente relacionado con la resistencia aeróbica y el vínculo entre este y la capacidad de recuperación de los futbolistas.

SÍNTESE O consumo máximo de oxigênio é considerado um indicador diretamente relacionado à resistência aeróbica, tornando esta capacidade um fator determinante no desempenho de um jogador de futebol. Conhecer os critérios teóricos nacionais que sustentavam a importância do VO2max na capacidade de recuperação no futebol foi um passo anterior para a formação de estratégias prospectivas de intervenção direta para a tomada de decisões. Neste sentido, o objetivo da pesquisa foi determinar, consultando especialistas, os critérios existentes sobre a importância do VO2max na capacidade de recuperação dos jogadores de futebol. A pesquisa foi descritivo-correlacional com uma orientação exploratória; 13 especialistas foram pesquisados e deram critérios sobre cinco indicadores. A importância da resistência aeróbica no treinamento de futebol obteve uma pontuação de (X4,62) e em relação ao resto das capacidades físicas aplicadas ao futebol a (X3,23); a importância do VO2max no processo de gerenciamento a (X4,46); a correlação entre VO2max e recuperação a (X4,54) e a necessidade de aperfeiçoar a resistência aeróbica no futebol equatoriano a (X4). O índice de concordância entre especialistas obteve um nível aceitável (w=0,527). Todos os indicadores de análise obtiveram uma qualificação entre alto e muito alto, portanto a pesquisa destacou a importância teórica dada pelos especialistas sobre o consumo máximo de oxigênio como um indicador diretamente relacionado à resistência aeróbica e a ligação entre esta e a capacidade de recuperação dos jogadores de futebol.

The maximum oxygen consumption is considered an indicator directly related to aerobic endurance, so this capacity becomes decisive in the performance of the soccer player. Knowing the national theoretical criteria that supported the importance of VO2max in the recovery capacity in soccer was a previous step towards shaping prospective strategies of direct intervention for decision making. In this sense, the objective of the research was to determine, by consulting specialists, the existing criteria of the importance of VO2max in the recovery capacity of soccer players. The research was descriptive-correlational with an exploratory orientation; 13 specialists were surveyed who issued criteria on five indicators. The importance of aerobic endurance in soccer training obtained a score of (X 4.62) and in relation to the rest of the physical capacities applied to soccer a (X3.23); the importance of VO2max in the direction process a X 4.46); the correlation between VO2max and recovery a (X 4.54) and the need to improve aerobic endurance in Ecuadorian soccer a (X 4). The concordance index between specialists obtained an acceptable level (w=0.527). All the analysis indicators obtained a qualification between high and very high, so the research highlighted the theoretical importance provided by specialists on maximum oxygen consumption as an indicator directly related to aerobic endurance and the link between this and the ability to recovery of footballers.

Cambios enzimáticos durante el entrenamiento anaeróbico láctico y su influencia en la capacidad aeróbica / Enzymatic changes during lactic anaerobic training and their influence on aerobic capacity

Introducción: El entrenamiento deportivo es un proceso que requiere una planificación orientada a la adaptación del cuerpo a las cargas internas versus cargas externas; de allí, surge la necesidad de conocer el comportamiento de algunas enzimas musculoesqueléticas a través del control bioquímico y fisiológico del entrenamiento en el atletismo de medio fondo. Objetivo: Analizar los cambios enzimáticos de la creatinfosfoquinasa y la lactodeshidrogenasa durante el entrenamiento anaeróbico láctico y su influencia en la capacidad aeróbica en atletas de medio fondo. Método: Se utilizó el método descriptivo comparativo con una muestra de 20 sujetos aleatorizados en dos grupos: experimental y control; el análisis se realizó bajo el modelo estadístico Anova descriptiva, pruebas T y diseño de medidas repetidas con un intervalo del 95 por ciento de confianza (p<0,05). Resultados: En las variables creatinfosfoquinasa y lactodeshidrogenasa inicial y final no hubo variaciones significativas intergrupos; se observaron diferencias en la creatinfosfoquinasa en varianza (p=0,022) del orden del 97,8 por ciento; que en promedio (p=0,088) representó los niveles alcanzados del 91,2 por ciento. En las medidas repetidas no se presentaron cambios estadísticamente significativos intergrupos. Para la variable del VO2máx se aplicó la prueba T para comparar los estados inicial y final en cada grupo y hubo diferencias en ambos grupos (control p=0,002; experimental p=0,000). Conclusiones: No hubo cambios enzimáticos importantes durante los entrenamientos anaeróbico láctico y aeróbico, a su vez, el entrenamiento anaeróbico láctico si tuvo influencia en la capacidad aeróbica(AU)

Introduction: Sports training is a process that requires a planning oriented to the adaptation of the body to internal loads versus external loads; from there, arises the need to know the behavior of some musculoskeletal enzymes through the biochemical and physiological control of training in middle-distance athletics. Objective: To analyze the enzymatic changes of creatine phosphokinase and lactodehydrogenase during lactic anaerobic training and their influence on aerobic capacity in middle-distance athletes. Methods: The descriptive comparative method was used with a sample of 20 subjects randomized in two groups: experimental and control; the analysis was performed under the descriptive Anova statistical model, T-tests and repeated measures design with a 95 percent confidence interval (p<0.05). Results: In the initial and final creatine phosphokinase and lactodehydrogenase variables, there were no significant intergroup variations; differences were observed in creatine phosphokinase regarding variance or standard deviation (p=0.022) in the order of 97.8 percent; which in average (p=0.088) represented the levels reached of 91.2 percent. In the repeated measures, there were no statistically significant intergroup changes. For the VO2max variable, the T-test was applied to compare the initial and final states in each group and there were differences in both groups (control p=0.002; experimental p=0.000). Conclusions: There were no important enzymatic changes during lactic anaerobic and aerobic training, and lactic anaerobic training had an influence on aerobic capacity(AU)

Does Altitude of Birth Influence the Performance of National- to Elite-Level Colombian Cyclists?

OBJECTIVE: To determine whether the altitude of birth/childhood influences the values in peak power output (PPO) and estimated maximum oxygen uptake (estVO2max) in male Colombian road cyclists of different performance levels. This study also aimed to determine whether cyclists born at high altitudes tend to be more successful. METHODS: Eighty riders aged between 17 and 22 years of 3 performance levels (U23 world-class level, WC, n = 8; U23 national level, N23, n = 41; junior national level, J, n = 31) and 3 altitude levels (<800 m, low; 800-2000 m, moderate; >2000 m, high) performed an ergocycle maximal incremental test to exhaustion at an altitude of 2570 m. RESULTS: Altogether, while cyclists born at an altitude >2000 m represented ∼50% of the analyzed sample, there was a significantly higher proportion (84%) of these cyclists who had participated as professionals in a Grand Tour (χ2[1, N = 80] = 4.58, P < .05). Riders of the low group had lower values of PPO and estVO2max than cyclists of moderate and high altitudes, while no differences were noted between moderate- and high-altitude groups. In N23, PPO and estVO2max were lower in the low- than in the moderate-altitude group, while in the J cyclists, PPO and estVO2max were lower in the low-altitude compared with both moderate- and high-altitude groups. DISCUSSION: Among the cyclists tested at altitude in junior and U23, there is an overrepresentation of individuals who reached an elite level and were born at a high altitude (>2000 m). As no clear differences were observed between moderate- and high-altitude cyclists, the higher prevalence of elite cyclists in the latter group may originate from various-still unclear-mechanisms.

Exercise capacity in people with haemophilia: A systematic review.

INTRODUCTION: Exercise capacity has been established as a protective factor against joint impairment in people with haemophilia (PWH). However, little is known about how exercise capacity is affected in PWH. AIM: To analyse exercise capacity, as assessed by standardised laboratory or field tests in PWH. METHODS: A systematic review was conducted to identify manuscripts investigating physical capacity in PWH. An electronic search of PubMed/MEDLINE, Embase, Web of Science, CENTRAL and CINAHL was conducted from inception to 13 April, 2022. Two independent reviewers performed data extraction and assessed study quality using the critical appraisal tools of the Joanna Briggs Institute. RESULTS: Nineteen studies with 825 patients were included. Most studies used the six-min walk test (6MWT) or peak/maximal oxygen consumption (VO2 max). In children, the distance walked ranged from 274 ± 36.02 to 680 ± 100 m. In adults, the distance walked ranged from 457.5 ± 96.9 to 650.9 ± 180.3 m. VO2 max ranged from 37 ± 8 to 47.42 ± 8.29 ml kg-1  min-1 . Most studies reported lower values of exercise capacity compared to standardised values. Overall, the quality of the studies was moderate. CONCLUSION: Most of the studies showed that PWH have lower exercise capacity compared to reference values of 6MWT or VO2 max. Based on these results, it is necessary to emphasise in both the promotion and the prescription of physical exercise in PWH.

Hydrolyzed whey protein enriched with glutamine dipeptide attenuates skeletal muscle damage and improves physical exhaustion test performance in triathletes.

Purpose: To investigate the effects of hydrolyzed whey protein enriched with glutamine dipeptide on the percentage of oxygen consumption, second ventilatory threshold, duration and total distance covered, and skeletal muscle damage during an exhaustion test in elite triathletes. Methods: The study was a randomized, double-blinded, placebo-controlled, crossover trial. Nine male triathletes performed a progressive incremental test on a treadmill ergometer (1.4 km h-1·3 min-1) 30 min after ingesting either 50 g of maltodextrin plus four tablets of 700 mg hydrolyzed whey protein enriched with 175 mg of glutamine dipeptide diluted in 250 ml of water (MGln) or four tablets of 700 mg maltodextrin plus 50 g maltodextrin diluted in 250 ml of water (M). Each athlete was submitted to the two dietary treatments and two corresponding exhaustive physical tests with an interval of one week between the interventions. The effects of the two treatments were then compared within the same athlete. Maximal oxygen consumption, percentage of maximal oxygen consumption, second ventilatory threshold, and duration and total distance covered were measured during the exhaustion test. Blood was collected before and immediately after the test for the determination of plasma lactate dehydrogenase (LDH) and creatine kinase (CK) activities and lactate concentration (also measured 6, 10, and 15 min after the test). Plasma cytokines (IL-6, IL-1ß, TNF-α, IL-8, IL-10, and IL-1ra) and C-reactive protein levels were also measured. Results: A single dose of MGln increased the percentage of maximal oxygen consumption, second ventilatory threshold duration, and total distance covered during the exhaustion test and augmented plasma lactate levels 6 and 15 min after the test. MGln also decreased plasma LDH and CK activities indicating muscle damage protection. Plasma cytokine and C-reactive protein levels did not change across the study periods. Conclusion: Conditions including overnight fasting and a single dose of MGln supplementation resulted in exercising at a higher percentage of maximal oxygen consumption, a higher second ventilatory threshold, blood lactate levels, and reductions in plasma markers of muscle damage during an exhaustion test in elite triathletes. These findings support oral glutamine supplementation's efficacy in triathletes, but further studies require.

Validation of Maximal, Submaximal, and Nonexercise Indirect [Formula: see text]O2max Estimations at 2600 m Altitude.

Aim: To study the criterion validity of three indirect maximal oxygen uptake ([Formula: see text]O2max) assessment equations at altitude. Methods: We studied 64 young adults (53% men) at Bogota, Colombia (2600 m altitude). Direct [Formula: see text]O2max was measured by indirect calorimetry using a maximal incremental treadmill protocol. Indirect [Formula: see text]O2max was estimated by two exercise field tests (the 20-m shuttle-run test [20-MST] and the 2-km walking test (UKK)) and one nonexercise method (the perceived functional ability-physical activity rating questionnaire [PFA-PAR]). Altitude-adjusted PFA-PAR was estimated as a 13% linear reduction in PFA-PAR. We calculated Lin concordance coefficients (LCC) and standard error of the estimates (SEEs), and we performed Bland-Altman analyses for each indirect method. Results: Mean [Formula: see text]O2max was 41.2 ± 5.8 mL/kg/min in men and 32.2 ± 3.6 mL/kg/min in women. We found the highest agreement with direct [Formula: see text]O2max for the 20-MST (LCC = 0.79, SEE = 3.91 mL/kg/min), followed in order by the altitude-adjusted PFA-PAR (LCC = 0.71, SEE = 4.12 mL/kg/min), the UKK (LCC = 0.67, SEE = 5.48 mL/kg/min), and the unadjusted PFA-PAR (LCC = 0.57, SEE = 4.75 mL/kg/min). The unadjusted PFA-PAR tended to overestimate [Formula: see text]O2max, but Bland-Altman analysis showed that this bias disappeared after altitude adjustment. Conclusion: Several maximal, submaximal, and nonexercise methods provide estimates of [Formula: see text]O2max with acceptable validity for use in epidemiological studies of populations living at moderate altitude.

Long-term low-level laser therapy promotes an increase in maximal oxygen uptake and exercise performance in a dose-dependent manner in Wistar rats.

The use of low-level laser therapy (LLLT) represents a new intervention modality that has been explored to enhance exercise performance. The aim of this study was to evaluate the influence of LLLT (GaAIAs-850 nm) at different doses on VO2max and on exercise performance in rats. Male Wistar rats were divided into three groups: "placebo" rats (P-LLLT, n = 10), rats at a dose of 0.315 J per treatment point of LLLT (8.7 J/cm(2)-LLLT, n = 10), and rats at a dose of 2.205 J per treatment point of LLLT (61.2 J/cm(2)-LLLT, n = 10). The LLLT was applied bilaterally at the biceps femoris, gluteus, lateral and medial gastrocnemius, iliopsoas, and adductor longus muscles. One spot in each muscle belly was applied, with a sum of 12 spots in each rat, once a day, for 10 days. All animals performed the maximal exercise test (ET) at a metabolic treadmill for rats, with simultaneous gas analysis. The distance covered was measured during ET, before and after the conclusion of the LLLT protocol. The data were compared by a repeated measures two-way ANOVA followed by the Student-Newman-Keuls post hoc tests (p < .05). The 61.2 J/cm(2)-LLLT group increased VO2basal (~40 %), VO2max (~24 %), VCO2max (~17 %), and distance covered (~34 %) after LLLT application on the skeletal muscle. No significant results were found comparing before and after conditions for the studied variables considering P-LLLT and 8.7 J/cm(2)-LLLT groups. The LLLT promoted in a dose-dependent manner an increase in oxygen consumption uptake and a performance increment of male Wistar rats.

Vo2max estimadoppor equações preditivas apresena baixa concordância com o obtiido pelo teste cardiopulmonar - padrão ouro / Vo2maxestimated by predictive equatios presents low concordance withh that obtained by cardiopulmonary test - gold standard

RESUMOO objetivo foi avaliar a concordância entre mensurações do VO2maxobtidas em teste cardiopulmonar de exercício versus obtidas por equações preditivas. Homens (21-55 anos) foram agrupados em praticantes de musculação (PM; n=31) e corridas (PC; n=28) e não praticantes (SE; n=35). Testou-se 5 equações, uma delas elaborada a partir de amostra brasileira. A concordância foi avaliada por Bland-Altman e as correlações pelo coeficiente de correlação de Pearson (r). Os r entre medida padrão ouro vs. equações ficaram entre 0,27 a 0,75, com p<0,05 para a maioria. Entretanto, as concordâncias foram baixas. Na equação obtida em brasileiros, os valores menos concordantes foram, em ordem: SE, PM e PC; nas demais equações foram: PC, PM e SE. As piores estimativas foram para VO2maxmais elevados, principalmente >40 mL.kg-1.min1. Conclui-se que as equações preditivas avaliadas nesse estudo geraram medidas de baixa concordância quando comparadas ao padrão ouro, principalmente para VO2max>40 mL.kg-1.min-1.

ABSTRACTThe aim was to evaluate the concordance between measurements of VO2max obtained by exercise cardiopulmonary test (gold-standard) vs. that obtained by predictive equations. Men (21-55 years-old) were grouped into Resistance training (RT; n=31), long-distance runners (R; n=28) and non-exercise practitioners (C; n=35). Five equations were tested, one of them made from Brazilian sample. The concordance was evaluated by Bland-Altman, and correlation analysis by Pearson's coefficient (r). The r between gold-standard vs. equations ranged 0.27 to 0.75, with p<0.05 for the most analysis, however, with low concordance. Regarding the equation obtained in Brazilians, the values with lower concordance were, following the order: C, RT and R. In relation to others equations, again with lower concordance, the order was R, RT and C. The worst estimates were to higher VO2max values, mainly for >40 mL.kg-1.min-1. In conclusion, the predictive equations tested generate low concordance when compared to VO2maxgold-standard test, mainly for VO2max>40 mL.kg-1.min-1.

Provável reserva neurofisiológica na execução de exercícios aeróbios máximos / Probable reserves neurophysiological in the execution of maximum aerobic exercises

O modelo tradicional de fisiologia do exercício assume que existe um limite periférico (muscular) em todo exercício aeróbio máximo, devido à hipóxia severa causada pela oferta inadequada de oxigênio ao músculo esquelético. Este evento seria coincidente com o recrutamento de todas as unidades motoras disponíveis no músculo ativo, no mesmo instante. Entretanto, evidências recentes não se ajustam a estas predições. Pelo contrário, um modelo de regulação central do esforço defende a existência de reserva neurofisiológica em todo exercício aeróbio máximo. Nessa nova interpretação, o sistema nervoso central (SNC) modularia o recrutamento muscular para impedir a ativação de todas as unidades motoras ao mesmo tempo, e evitar o excesso de dano à matriz celular. Tal modulação realizada pelo SNC seria um mecanismo natural de defesa do organismo contra a falha catastrófica e o rigor mortis. Alguns resultados obtidos pelo Grupo de Estudo em Psicofisiologia do Exercício poderiam ser interpretados de acordo com a presença de uma reserva neurofisiológica, pois a potência mecânica máxima (WMAX) num teste incremental máximo foi aumentada após ingestão de cafeína e placebo percebido como cafeína, porém, sem alteração no consumo máximo de oxigênio (VO2MAX), sugerindo não haver limitação periférica. Entretanto, estudos devem ser desenhados para responder essa questão de forma mais consistente, incluindo medidas metabólicas e de excitabilidade dos músculos esqueléticos, mas também do SNC, durante exercício.

The traditional model of exercise physiology assumes that there would be a peripheral (muscular) limit in maximal aerobic exercises due to severe hypoxia derived from inadequate oxygen supply to the skeletal muscles. This event is to be coincident with the total recruitment of available motor units in the active muscles. However, recent evidence does not agree with these predictions. Rather, a centrally-regulated effort model argues that there is a neurophysiological reserve in all maximal aerobic exercises. In this new interpretation the central nervous system (CNS) would modulate the muscle recruitment to prevent the recruitment of all available motor units at the same time in order to avoid excessive harm in cellular matrixes. Such modulation performed by the CNS would be a natural mechanism to defend the body against catastrophic failure and rigor mortis. Some results obtained by the Exercise Psychophysiology Research Group may be interpreted according to this neurophysiological reserve as the peak power output (WPEAK) in a maximum incremental test was increased after caffeine and placebo perceived as caffeine ingestion, but without change in maximal oxygen consumption (VO2MAX), suggesting no peripheral limitation. Yet, studies including measures of metabolic and skeletal muscle excitability in addition to the CNS function during exercise may answer this question closer.

Impact of exercise training on redox signaling in cardiovascular diseases.

Reactive oxygen and nitrogen species regulate a wide array of signaling pathways that governs cardiovascular physiology. However, oxidant stress resulting from disrupted redox signaling has an adverse impact on the pathogenesis and progression of cardiovascular diseases. In this review, we address how redox signaling and oxidant stress affect the pathophysiology of cardiovascular diseases such as ischemia-reperfusion injury, hypertension and heart failure. We also summarize the benefits of exercise training in tackling the hyperactivation of cellular oxidases and mitochondrial dysfunction seen in cardiovascular diseases.

Avaliação da capacidade cardiorrespiratória (vo2máx) em policiais militares, com testes indiretos / Assessment of cardiorespiratory fitness (VO2máx) in the military police of, with indirect tests

O objetivo deste estudo foi avaliar o (VO2máx) de militares com testes indiretos de 1600m (ALMEIDA et al., 2010) e 12min (COOPER,1968). Participaram 49 militares masculinos, aptos fisicamente, média de idade de 25,6 ±3,10 anos, IMC 23 ±1,4 Kg.m2, selecionados aleatoriamente. O (VO2máx) foi mensurado através das equações de Cooper e Almeida após os testes; coletados e analisados os parâmetros fisiológicos: frequência cardíaca, glicemia e lactato pré e pós-testes e percepção subjetiva do esforço ao final. Observou-se grande fidedignidade entre eles, sendo o valor do (VO2máx) de 1600m (43,63±3,21) superior ao de 12min (39,42±4,18), mostrando aumento significativo (p<0,0001), atribuída à potência de exercício desenvolvida durante o teste, que pode ser observada nos valores de lactato no de 1600m. A prova de 1600m, mostrou-se como uma alternativa eficaz na mensuração do (VO2máx) em militares, portanto sendo uma medida indireta de baixo custo e fácil uso e de grande valia sua aplicabilidade nas Instituições Militares.

The objective of this research was to evaluate the (VO2máx), in indirect tests of 1600m (Almeida et al., 2010) and 12 min (Cooper, 1968). 49 physically fit military aged 25.6±3.10 years, BMI23±1.4 kg.m2, where randomly chosen according to the inclusion criteria of the research took part of it. The (VO2máx) was measured through COOPER and Almeida equations after the tests of 1600m and 12min run, collected and analyzed physiological parameters of cardiac frequency glycemia and lactate were collected before and after the tests. Besides, the subjective perception of effort at the end of each test was evaluated. Through the physiological parameters, it could be observed a great reliability between the 1600m and 12min run tests, in which the (vo2máx) value in the former (43.63±3.21) was higher than in the latter test (39.42±4.18), showing a significant incriase (p<0.0001), attributed to the power developedduring the exercise test, which can be observed for lactate in the 1600m. The 1600m test, proved to be an effective alternative in measuring (vo2máx) in milytary, being an indirect measure of cost and ease of use and great value for their applicability in the military institutions.

Alteraciones musculares periféricas en la enfermedad de Chagas

La enfermedad de Chagas sigue siendo un problema en Venezuela y en varios países de Latinoamérica. Este trabajo presenta datos sobre las alteraciones que esta enfermedad produce en los músculos esqueléticos periféricos, lo cual puede contribuir a la incapacidad funcional que presentan muchos de los pacientes. Fueron estudiados 19 pacientes con enfermedad avanzada, a quienes se les hizo evaluación cardiorrespiratoria, ecocardiograma, prueba de ejercicio y biopsia del músculo cuádriceps. El 42% presentó incapacidad funcional moderada a severa, medida por el consumo máximo de oxígeno, que estuvo relacionada con cambios morfológicos y metabólicos en las fibras musculares. Se hallaron alteraciones en la microvasculatura muscular compatibles con daño autoinmune. En conclusión, los pacientes con enfermedad de Chagas sufren alteraciones en la musculatura periférica que puede contribuir a la incapacidad funcional y al grado de afectación por esta enfermedad. La determinación de la capacidad funcional debería agregarse a la evaluación de la enfermedad

Chagas disease is still a problem in Venezuela and other Latin American countries, in spite of efforts to control the disease. Peripheral muscle alterations that contribute to decreased functional capacity in moderate to advanced Chagas’ disease patients are analyzed in the present work. Nineteen Chagas’ disease patients were studied, including cardio-respiratory evaluation, echocardiogram, exercise test and quadriceps muscle biopsy. The results showed 42% patients with moderate to severe decrease of maximal oxygen consumption. Muscle biopsies presented morphologic and metabolic alterations, some related to functional capacity. Capillary vessel damage in muscle was similar to that found in autoimmune diseases. In conclusion, Chagas’ disease patients showed peripheral muscle alterations related to decreased functional capacity. The functional capacity changes may contribute to the severity of the disease and should be added to the evaluation of the patients