The Effects of Weight Loss on Neuroadrenergic Function

Elevated subconscious nervous system activity is a characteristic of the obese state and contributes importantly to the risk of heart disease and diabetes. This project will compare sympathetic nervous system activity and function in a group of obese persons with differing levels of sugar tolerance (normal, impaired and type 2 diabetic). Inter-relationships with insulin action, blood pressure, heart and kidney function will be determined before and after a 4-month weight loss and 3-month weight loss maintenance program. It is hypothesized that the transition from normal sugar tolerance to impaired sugar tolerance to type 2 diabetes will be accompanied by escalating sympathetic nervous system dysfunction. Furthermore, that weight loss will favorably improve sympathetic function, with greatest benefits occurring in those subjects who are insulin resistant with high blood insulin concentration.