Sympathetic Nervous System Activity Is Associated With Obesity-Induced Subclinical Organ Damage in Young Adults

Abstract

Abstract-Excess weight is established as a major risk factor for cardiovascular diseases, particularly in young individuals.To get a better understanding of the pathophysiology underlying increased cardiovascular disease risk, we evaluated early signs of organ damage and their possible relationship to sympathetic nervous activity. Eighteen lean (body mass index Ͻ25 kg/m 2 ) and 25 overweight or obese (body mass index Ͼ25 kg/m 2 ) healthy university students were included in the study. We comprehensively assessed subclinical target organ damage, including the following: (1) assessment of renal function; (2) left ventricular structure and systolic and diastolic function; and (3) O besity is an established risk factor for cardiovascular disease (CVD) development. 1 Although excess adiposity is frequently linked with metabolic abnormalities such as elevated triglycerides, low levels of high-density lipoprotein (HDL), elevated glucose, elevated blood pressure (BP), insulin resistance, and a proinflammatory state, most likely contributing to excess CVD, 2 large scale epidemiological studies have shown that the CVD risk associated with obesity remains appreciable even after correction for these factors. 1,3 Perhaps surprising is the finding that the obesity-related relative risk of death from stroke and all of the CVDs combined is higher in younger than in older subjects, 4,5 indicating that excess adiposity is likely to have deleterious effects on the cardiovascular system already at an early age, well before clinical manifestations of CVD become apparent. In agreement with this view, recent studies have demonstrated that the presence of obesity since childhood was the only consistent and significant determinant of adverse cardiac remodeling 6 and that being overweight at age 20 years or obese at any time in life was linked with a 3-fold increased risk of developing chronic renal failure. 7 Moreover, functional and structural abnormalities of the endothelium are already evident in obese children aged 9 to 12 years. 8 Given that the sympathetic nervous system (SNS) is an important regulatory mechanism of both metabolic and cardiovascular functions, altered SNS may likely play a role in the etiology and complications of obesity. 9 It is now well established that obesity is associated with elevated SNS Continuing medical education (CME) credit is available for this article. Go to http://cme.ahajournals.org to take the quiz.

Deep breathing improves blunted baroreflex sensitivity even after 30 years of type 1 diabetes

“…As such, it cannot be excluded as playing at least a part in our patients as well. Endothelial dysfunction and low-grade inflammation have also been related to autonomic imbalance [37][38][39] and could modify the resting level of autonomic function and BRS. Preliminary findings from our group suggest in addition a possible role of chronic tissue hypoxia.…”

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“…Obesity, which is frequently associated with sympathetic nervous activation, is an important factor in the progression and perhaps even in the initiation of CKD, 39,40 and abdominal obesity is a relevant risk factor for death and cardiovascular complications in those with CKD. 20,41 Obesity, itself, contributes to the development and progression of CKD, independent of elevated BP or diabetes.…”

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“…96) In particular, the enhanced activation of the sympathetic nervous system is closely associated with organ damage in obesity hypertension. 97) Body weight reduction showed an improvement in metabolic measures, indices of infl ammation, endothelial dysfunction, and sympathetic over-reactivity, 98) suggesting a complex interaction between these systems. However, evidence concerning the interaction between multiple systems remains scarce, and further explorations are required.…”