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Book Synopsis Skeletal Muscle Blood Flow Responses to Exercise in Metabolic Syndrome by :
Download or read book Skeletal Muscle Blood Flow Responses to Exercise in Metabolic Syndrome written by and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metabolic syndrome is present in nearly one third of the United States population. Adults with MS are obese, hypertensive, hyperglycemic, dyslipidemic, and at high risk of developing cardiovascular disease and diabetes. Physical activity is an effective non-pharmacological way to combat the syndrome. Research in animal models of metabolic syndrome suggests blood flow responses to exercise are impaired due to altered vascular control mechanisms. Impaired blood flow and/or altered vascular control during exercise can adversely affect oxygen delivery, metabolic waste removal, glucose disposal, and blood pressure regulation - all of which may be especially detrimental in this population and may accelerate development of cardiovascular disease and type 2 diabetes. Whereas previous work in animals has identified multiple signaling pathways that may be altered in metabolic syndrome, this was the first series of studies to attempt to translate such findings to human metabolic syndrome. The overall goal of this dissertation was to gain insight into exercise blood flow control in human metabolic syndrome. The specific aims were to determine: 1) whether adult humans with metabolic syndrome exhibit blunted exercise-induced skeletal muscle blood flow, 2) whether blood flow responses in metabolic syndrome are attenuated with additional physiological stress, 3) whether adults with metabolic syndrome exhibit increased alpha-adrenergic vasoconstriction during exercise, and 4) whether alpha-adrenergic vasoconstriction during exercise is related to muscle sympathetic nerve activity. To test our hypotheses, we measured forearm blood flow (Doppler ultrasound) during dynamic forearm exercise in adults with metabolic syndrome and healthy controls. The first project measured vascular responses under both normoxic and hypoxic conditions. The second project directly and specifically assessed adrenergic responsiveness using intra-arterial infusion of alpha-adrenergic receptor agonists. Muscle sympathetic nerve activity (microneurography of the peroneal nerve) was measured to explore the link between sympathetic nerve activity, vascular responsiveness, and blood flow control during exercise. The projects included in this dissertation provide a better understanding of the pathophysiology of human metabolic syndrome and highlight the importance of integrative vascular control in both health and disease. In addition, results provide translationally relevant outcomes that will be useful in designing and interpreting future studies in human metabolic syndrome.
