Effect of Self-Regulated Exercise Intensity on Endothelial Function in Men with Coronary Artery Disease: 2663

PURPOSE: Cardiovascular disease (CVD) is the leading cause of death in the Ireland and the EU and kills more people than all cancers combined. It accounts for 55% of all deaths in women across Europe and 43% of all deaths in men. The cost to the EU economy is 169 billion euro/year. Endothelial dysfunction induced by cardiovascular risk factors is considered to be one of the earliest stages in vascular damage and is associated independently with cardiovascular events. The balance between endothelial lesion and regeneration is critical for the maintenance of vessel integrity. Exposure to cardiovascular risk factors alters the homeostatic regulatory functions of the endothelium, subsequently progressing to pro-inflammatory activation, apoptosis, and undesirable vessel remodelling. The purpose of this study is to examine the effect of self-regulated exercise intensity on endothelial function in men with coronary artery disease.METHODS: Eight men with coronary artery disease (65.7 ± 4.5 yr, VO2max 18.6 ± 4.1 ml/kg/min, BMI 29.7±3.3 kg/m-2) underwent 20 min of treadmill walking at a self-regulated intensity. Endothelial dependent dilation of the brachial artery was assessed before and 1 h following the acute bout of exercise. Vessel diameter was determined using high resolution vascular ultrasonography (SonoSite, MicroMaxx) from flow mediated dilation (FMD) following 5 min of forearm occlusion. Endothelial independent vasodilation was measured at min 3, min 4 and min 5 following the administration of glyceryl trinitrate (0.4 mg).RESULTS: The subjects self-selected an average treadmill walking speed of 5.3 km/h and a grade of 0.7%. This intensity equated to 65.7% VO2max, and an RPE-O of 12.0. Compared to baseline, FMD was significantly increased (1 min (4.6 v 10.7%) and 3 min (6.2 v 11.0) post occlusion) at 60 min following the acute bout of self-regulated exercise. There was no change in endothelial independent dilation in response to the acute bout of exercise.CONCLUSION: These results indicate a beneficial effect of self regulated exercise on endothelial dependent vascular function in men with coronary artery disease

Relation Between Endothelial Microparticles and Endothelial Function Following Acute Exercise in Men with CAD: 2652

PURPOSE: Microparticles (MP) are small membranous vesicles shed from formed elements such as circulating platelets and vascular endothelial cells. They express surface antigens characteristic of their cell-of-origin and contain DNA, RNA, miRNA and intracellular proteins. Depending on the dynamic morphological state of the parent cell, phenotypically varied MP may be released into the circulation. MP serve not only as markers, but also potential mediators of inflammation, coagulation and endothelial dysfunction. This study examined the relation between total MP, endothelial MP (EMP), platelet MP (PMP) and endothelial function (a validated surrogate measure of early atherosclerosis) in response to acute exercise in men with coronary artery disease (CAD).METHODS: Eight men with CAD (65.7 ± 4.5 yr, VO2max 18.6 ± 4.1 ml/kg/min, BMI 29.7±3.3 kg/m-2) underwent 20 min of treadmill walking at 66 % VO2max. Endothelial dependent dilation of the brachial artery was assessed before and 1 h following the acute bout of exercise. Vessel diameter was determined using high resolution vascular ultrasonography (SonoSite, MicroMaxx) from flow mediated dilation (FMD) following 5 min of forearm occlusion. Endothelial independent vasodilation (EID) was measured following the administration of glyceryl trinitrate (0.4 mg). MP counts were enumerated by flow cytometry from platelet poor plasma (PPP) stored at -80°C. MP were characterized based on size (0.5 - 1.0 μm sizing gate) and their ability to bind annexin V. MP had also to bind to CD62E or CD41 to be of endothelial or platelet origin respectively.RESULTS: Compared to baseline, FMD was significantly increased at 60 min following the acute bout of exercise. There was no change in EID. There was significant relation between the percent change in total MP (annexin V+ events) and the percent changes in flow mediated dilation 60 min after the exercise bout and between the percent change in EMP (annexin V+/CD62E+ events) and the percent changes in flow mediated dilation 60 min after the exercise bout.CONCLUSION: Changes in endothelial function in response to acute exercise may be mediated by alterations in circulating levels of MP

Physiological and Perceptual Responses during Self-Regulated Exercise in Men with Coronary Artery Disease: 1872

PURPOSE: Physiologically based exercise prescriptions normally involve identifying an intensity range that elicits a predetermined VO2 or heart rate. In many instances prescribed exercise that exceeds an individual's preferred level of intensity may establish a negative attitude toward physical activity. Longitudinal studies report that participants tend to deviate from physiologically based prescribed levels of intensity in favour of their apparently preferred levels. Self-regulated exercise intensity may increase enjoyment and promote adherence by allowing individuals successfully complete an activity within their perceptual preference range and without undue physiological strain. This study examined the physiological and perceptual responses during self-regulated exercise in men with CAD.METHODS: Eight men with CAD (65.7 ± 4.5 yr, VO2max 18.6 ± 4.1 ml/kg/min, BMI 29.7±3.3 kg/m-2) exercised on a treadmill for 20 min at a self-regulated intensity. They were allowed to change the velocity and grade every 5 min. Respiratory metabolic and gas exchange variables were measured continuously using open circuit spirometry. Heart rate was continuously recorded using telemetry, and undifferentiated RPE (RPE-O) was recorded every 5 min using the Borg 15-category scale.RESULTS: Perceptual and physiological responses remained stable after the first 5 min of exercise. Subjects exercised at 65.7 ± 14.2 % VO2max and 94 ± 5.0 % HRpeak during the final 15 min of self regulated exercise. This equates to a treadmill velocity of 5.3 ± 0.9 km/h, and a grade of 0.7 ± 1.1. The RPE-O was 12.0 ± 2.0, and falls between the verbal descriptors of fairly light and somewhat hard.CONCLUSION: When allowed to self-regulate their exercise intensity, men with CAD select an intensity that is perceived to be fairly light to somewhat hard, and elicits a physiological response likely to improve cardiovascular health