191 research outputs found

    Type 2 diabetes and reduced exercise tolerance: A review of the literature through an integrated physiology approach

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    The association between type 2 diabetes mellitus (T2DM) and heart failure (HF) is well established. Early in the course of the diabetic disease, some degree of impaired exercise capacity (a powerful marker of health status with prognostic value) can be frequently highlighted in otherwise asymptomatic T2DM subjects. However, the literature is quite heterogeneous, and the underlying pathophysiologic mechanisms are far from clear. Imaging-cardiopulmonary exercise testing (CPET) is a non-invasive, provocative test providing a multi-variable assessment of pulmonary, cardiovascular, muscular, and cellular oxidative systems during exercise, capable of offering unique integrated pathophysiological information. With this review we aimed at defying the cardiorespiratory alterations revealed through imaging-CPET that appear specific of T2DM subjects without overt cardiovascular or pulmonary disease. In synthesis, there is compelling evidence indicating a reduction of peak workload, peak oxygen assumption, oxygen pulse, as well as ventilatory efficiency. On the contrary, evidence remains inconclusive about reduced peripheral oxygen extraction, impaired heart rate adjustment, and lower anaerobic threshold, compared to non-diabetic subjects. Based on the multiparametric evaluation provided by imaging-CPET, a dissection and a hierarchy of the underlying mechanisms can be obtained. Here we propose four possible integrated pathophysiological mechanisms, namely myocardiogenic, myogenic, vasculogenic and neurogenic. While each hypothesis alone can potentially explain the majority of the CPET alterations observed, seemingly different combinations exist in any given subject. Finally, a discussion on the effects -and on the physiological mechanisms-of physical activity and exercise training on oxygen uptake in T2DM subjects is also offered. The understanding of the early alterations in the cardiopulmonary response that are specific of T2DM would allow the early identification of those at a higher risk of developing HF and possibly help to understand the pathophysiological link between T2DM and HF

    Valoración de la capacidad cardiorrespiratoria y efectos del ejercicio físico en personas con hipertensión arterial primaria y sobrepeso u obesidad

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    164 p.Esta tesis doctoral la componen distintos estudios que se basan en (a) la creación yevaluación de una nueva ecuación aplicable al Modified Shuttle Walk Test (MSWT) para realizar lavaloración indirecta y el seguimiento de la capacidad cardiorrespiratoria (CCR) tras una intervenciónde ejercicio físico (EF), y (b) la comparación de los efectos que se producen en la CCR trasintervenciones de EF de intensidad, duración y tipo distintos.Métodos: entre los años 2011 y 2017, un total de 265 personas adultas y sedentarias diagnosticadascon hipertensión arterial (HTA) primaria y sobrepeso u obesidad participaron en el proyecto deinvestigación EXERDIET-HTA. Esas personas fueron aleatoriamente asignadas a uno de los gruposde intervención de EF aeróbico supervisado (entrenamiento continuo a intensidad moderada, MICT; oentrenamiento interválico a intensidad vigorosa, HIIT), o a un grupo control (CG). Antes de comenzary después de haber finalizado las intervenciones que duraron 8, 12 o 16 semanas, cada participanterealizó distintas pruebas de valoración, entre las que se incluyeron mediciones antropométricas, untest de esfuerzo cardiopulmonar con protocolo incremental en rampa sobre cicloergómetro, y un testde campo de velocidad incremental conocido como MSWT. Los dos test se desarrollaron hasta elagotamiento, o hasta obtener valores pico en la CCR. En ambos test se registraron valores dereposo, submáximos durante la prueba y valores pico de variables como la frecuencia cardiaca,percepción del esfuerzo, presión arterial, y distancia recorrida, así como variables ventilatorias en eltest cardiopulmonar, especialmente el consumo de oxígeno pico (V¿ O2pico), indicador predilecto de laCCR.Resultados: (a) el V¿ O2pico medido mostró una correlación fuerte (r = 0.72, P 0.8), principalmente debido al efecto del HIIT. Las mejoras en la CCR ocurrieron en lasintervenciones de EF supervisado de 12 y 16 semanas, y no en las de 8 semanas o CG quemostraron efectos pequeños.Conclusión: (a) los resultados indican que la estimación de la CCR a través de la ecuación creadapara ser aplicada al MSWT en personas con HTA primaria y sobrepeso u obesidad reporta un errorde estimación sustancial, sobre todo a la hora de hacer un seguimiento de la CCR tras unaintervención, por lo que su validez es cuestionable; este método de valoración podría tener utilidad enpersonas con HTA y obesidad (no sobrepeso), cuando la valoración directa con test cardiopulmonarno esté disponible. (b) este estudio muestra que las intervenciones con MICT y HIIT producen efectocardioprotector en personas con HTA primaria y sobrepeso u obesidad. Las intervenciones de cortaduración (< 12 semanas) no parecen ser efectivas para la mejora de la CCR, y el HIIT podría resultaren mayores ganancias de CCR, que parecen aumentar al alargar la duración de la intervención.Palabras clave: consumo de oxígeno pico, test de campo, ecuación de estimación, actividad física,diseño de ejercicio físico, enfermedad cardiovascular

    Valoración de la capacidad cardiorrespiratoria y efectos del ejercicio físico en personas con hipertensión arterial primaria y sobrepeso u obesidad

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    164 p.Esta tesis doctoral la componen distintos estudios que se basan en (a) la creación yevaluación de una nueva ecuación aplicable al Modified Shuttle Walk Test (MSWT) para realizar lavaloración indirecta y el seguimiento de la capacidad cardiorrespiratoria (CCR) tras una intervenciónde ejercicio físico (EF), y (b) la comparación de los efectos que se producen en la CCR trasintervenciones de EF de intensidad, duración y tipo distintos.Métodos: entre los años 2011 y 2017, un total de 265 personas adultas y sedentarias diagnosticadascon hipertensión arterial (HTA) primaria y sobrepeso u obesidad participaron en el proyecto deinvestigación EXERDIET-HTA. Esas personas fueron aleatoriamente asignadas a uno de los gruposde intervención de EF aeróbico supervisado (entrenamiento continuo a intensidad moderada, MICT; oentrenamiento interválico a intensidad vigorosa, HIIT), o a un grupo control (CG). Antes de comenzary después de haber finalizado las intervenciones que duraron 8, 12 o 16 semanas, cada participanterealizó distintas pruebas de valoración, entre las que se incluyeron mediciones antropométricas, untest de esfuerzo cardiopulmonar con protocolo incremental en rampa sobre cicloergómetro, y un testde campo de velocidad incremental conocido como MSWT. Los dos test se desarrollaron hasta elagotamiento, o hasta obtener valores pico en la CCR. En ambos test se registraron valores dereposo, submáximos durante la prueba y valores pico de variables como la frecuencia cardiaca,percepción del esfuerzo, presión arterial, y distancia recorrida, así como variables ventilatorias en eltest cardiopulmonar, especialmente el consumo de oxígeno pico (V¿ O2pico), indicador predilecto de laCCR.Resultados: (a) el V¿ O2pico medido mostró una correlación fuerte (r = 0.72, P 0.8), principalmente debido al efecto del HIIT. Las mejoras en la CCR ocurrieron en lasintervenciones de EF supervisado de 12 y 16 semanas, y no en las de 8 semanas o CG quemostraron efectos pequeños.Conclusión: (a) los resultados indican que la estimación de la CCR a través de la ecuación creadapara ser aplicada al MSWT en personas con HTA primaria y sobrepeso u obesidad reporta un errorde estimación sustancial, sobre todo a la hora de hacer un seguimiento de la CCR tras unaintervención, por lo que su validez es cuestionable; este método de valoración podría tener utilidad enpersonas con HTA y obesidad (no sobrepeso), cuando la valoración directa con test cardiopulmonarno esté disponible. (b) este estudio muestra que las intervenciones con MICT y HIIT producen efectocardioprotector en personas con HTA primaria y sobrepeso u obesidad. Las intervenciones de cortaduración (< 12 semanas) no parecen ser efectivas para la mejora de la CCR, y el HIIT podría resultaren mayores ganancias de CCR, que parecen aumentar al alargar la duración de la intervención.Palabras clave: consumo de oxígeno pico, test de campo, ecuación de estimación, actividad física,diseño de ejercicio físico, enfermedad cardiovascular

    The effect of structured exercise training on endothelial function in patients with coronary artery disease

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    Background: Endothelial function and arterial stiffness have shown to be predictive of cardiovascular risk. Aim: The study sought to investigate the effect of a current 8-week exercise based cardiac rehabilitation (CR) programme in the UK on endothelial function. Blood-borne biomarkers known to affect endothelial function including intracellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and C-Reactive Protein (CRP) were measured and correlated with measures of pulse wave velocity (PWV), a surrogate marker of arterial stiffness.Methods: Patients were randomised to either the intervention (exercise training) or control group (patients who were eligible but refused to participate in the CR programme) following a cardiac event 4-6 weeks prior to the start of CR. All patients were on optimal pharmacological therapy. The intervention consisted of 8 weeks x 2 sessions per week (a total of 16 supervised training sessions equivalent to Phase III) at 40-60% of heart rate reserve (HRR), starting with 10 min of exercise training and progressing to 30 min depending on individual progress in week 8. Baseline and 8-week measurements of PWV and blood-borne biomarkers of endothelial function including ICAM-1, VCAM-1 and CRP were measured.Results: 28 patients (mean age 62 ± 8 years; 86% male) were recruited (n=20 intervention; n=8 controls). There was a significant difference in the prevalence of Type 2 diabetes between the intervention and the control groups (P=0.004) at baseline. After 8 weeks, no statistically significant changes were found between groups for all measures of pulse wave velocity including cf-PWV, ba-PWV and aortic PWV (all P>0.05). Likewise, no changes were found between groups for blood-borne biomarkers including C- reactive protein, ICAM-1 and VCAM-1 (all P>0.05). There were no significant associations between PWV measures and blood biomarkers after 8 weeks. Weak associations were found between ba-PWV and ICAM-1 (r = -0.090, P=0.706), ba-PWV and VCAM-1 (r =0.304, P=0.192), and ba-PWV and CRP (r =0.317, P=0.174). In addition, there were no significant differences in cardiorespiratory fitness changes as a result of CR between groups (P=0.891).Conclusions: A short-term CR programme consisting of 16 supervised training sessions does not improve markers of adhesion, inflammation or arterial stiffness in patients with cardiovascular disease. Further investigation is required to determine the appropriate training volume to induce favourable adaptations in endothelial function

    New Applications of Cardiopulmonary Exercise Testing and Training in Paediatric Heart Disease

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    Congenital heart defects (CHD) have an incidence of 4-8/1000 live births and encompass a broad spectrum of disorders. Due to advances in cardiac surgery and cardiology care, most children born with CHD are now surviving into adulthood and there are currently more adults affected than children. Exercise capacity is reduced across the spectrum of patients with CHD, both in natural history and after surgical and interventional treatment. The aim of this project was to better understand exercise limitations and safety/usefulness of training in young patients with heart disease across a broad spectrum of disorders and in particular we focused on left-to-right shunts, systemic right ventricular physiology, univentricular physiology with Fontan palliation and dilated cardiomyopathy. Future perspective include exploring new ways of engaging teenagers with univentricular palliation in systemic and respiratory muscle training. Furthermore, the collaboration with biomedical engineers will allow us to gain in depth understanding of univentricular physiology. Similarities exisit in the physiological changes observed during exercise and pregnancy and the final goal is to implement the model with these variables to achieve better clinical outcome in this growing population of young adults with complex lesions and limited exercise and child-bearing potential. Exercise testing and training are becoming more and more relevant to guide therapy and management but also to assess the ability in daily activities that play an important role in many aspects of life that have not been addressed specifically until now. The increasing data available enable physicians to give adequate counseling regarding vocational or professional choices, suitable leisure activities and family planning according to the levels of activity considered safe and sustainable in the specific physiology. Further studies will warrant deeper understanding of issues that are specific to univentricular physiology and will help us to target interventions to improve quantity and quality of life

    Effects of high-intensity interval versus continuous exercise training on post-exercise heart rate recovery in coronary heart-disease patients.

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    Background: Heart rate recovery (HRR) has been considered a prognostic and mortality indicator in both healthy and coronary patients. Physical exercise prescription has shown improvements in VO2peak and HRR, but most of the studies have been carried out applying continuous training at a moderate intensity, being very limited the use of protocols of high intensity interval training in coronary patients. We aimed to compare the effects of a moderate continous training (MCT) versus a high intensity interval training (HIIT) programme on VO2 peak and HRR. Methods: Seventy three coronary patients were assigned to either HIIT or MCT groups for 8 weeks. Incremental exercise tests in a cycloergometer were performed to obtain VO2peak data and heart rate was monitored during and after the exercise test to obtain heart rate recovery data. Results: Both exercise programmes significantly increase VO2peak with a higher increase in the HIIT group (HIIT: 4.5± 4.46 ml/kg/min vs MCT: 2.46±3.57 ml/kg/min; P=0.039). High intensity interval training resulted in a significantly increase in HRR at the first and second minute of the recovery phase (15,44±7,04 vs 21,22 ±6,62, P <0,0001 and 23,73±9,64 vs 31,52±8,02, p <0,0001, respectively). Conclusions: The results of our research show that the application of HIIT to patients with chronic ischemic heart disease of low risk resulted in an improvement in VO2peak, and also improvements in post-exercise heart-rate recovery, compared with continuous training.pre-print792 K

    Short term physiological changes secondary to exercise in intermittent claudication : short term physiological changes in claudication

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    Background: In patients with intermittent claudication (IC), supervised exercise programmes (SEP) improve walking distance and quality of life (QoL); however the mechanisms by which these benefits are achieved remain unclear.Endothelial dysfunction is recognised as a trigger of the atheroinflammatory cascade and subsequent cardiovascular disease. In health, training improves cardiorespiratory physiology, inflammation and endothelial function. Changes in cardiorespiratory physiology, inflammatory markers and endothelial function are contradictory in IC.Objectives: This thesis aimed to assess the impact of SEP on cardiopulmonary physiology, endothelial function and athero-inflammatory markers in patients with IC.Methods: Following local research ethics committee and R & D approval, patients with IC were recruited from outpatient clinic. After providing informed written consent, patients underwent baseline assessment on two separate days.Session 1: participants completed a constant load treadmill test with pre and post exercise ankle brachial pressure indices.Session 2: measured QoL, endothelial function (EndoPAT2000, Itamar, Israel), venepuncture and a cardiopulmonary exercise test (CPET) using cycle ergometry. Participants then underwent a 12 week period of SEP which consisted of circuit training, with re-assessments at six and twelve weeks. The primary outcome measure was a 1.5ml/kg/min improvement in peak VO₂ after six weeks of exercise. Secondary outcomes included changes in endothelial function, quality of life, walking distance and inflammatory markers at both six and twelve weeks.Results: No significant improvements in CPET measurements, endothelial function or inflammation were demonstrated at any time point. Traditional markers of walking ability and QoL demonstrated an improvement by 12 weeks.Conclusions: The underlying mechanism through which exercise improves walking distance remains un-identified. Further work regarding the changes at the cellular level within the muscle is of importance
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