The present invention provides methods for determining whether to provide an inhibitor of sympathetic nervous system activity to a human being suffering from an autoimmune disease and/or fibromyalgia. The methods of this aspect of the invention each include the steps of: (a) measuring the heart rate variability of a human being suffering from an autoimmune disease or fibromyalgia, to yield heart rate variability data; (b) analyzing the heart rate variability data to determine whether there is excessive sympathetic nervous system activity in the heart of the human being; and (c) providing an inhibitor of sympathetic nervous system activity to the human being if there is excessive sympathetic nervous system activity in the heart of the human being.