Elevated sympathetic tone as an etiological factor of cardiometabolic disease

The sympathetic nervous system (SNS) plays a key role in both cardiovascular and metabolic regulation hence disturbances in SNS regulation are likely to impact on both cardiovascular and metabolic health. With excess adiposity, in particular when visceral fat accumulation is present, sympathetic activation commonly occurs. The cause and extent of sympathetic activation in obesity may be attributed to factors such as the release of adipokines from the adipose tissue, the existence of sleep apnoea, components of the metabolic syndrome, distribution and type of fat and underlying stress. Sympathetic activation may lead or further aggravate the elevation of blood pressure and end organ damage including vascular, cardiac and renal impairment. Weight loss achieved by either lifestyle changes including diet and exercise programs or bariatric surgery considerably decrease sympathetic tone, improve the cardiovascular and metabolic profile of obese subjects and decrease their cardiovascular risk. Whether some of the beneficial effects are due to an inhibitory effect on sympathetic nervous activity is not known. Given the lack of success in sustaining long term weight loss after diet or exercise the development of interventions and strategies that optimise weight loss but also limit obesity related cardio-metabolic disease development and progression is vital. Pharmacological and device based approaches to directly or indirectly target the activation of the SNS may offer some benefit in reducing the cardio-metabolic consequences of obesity.