 Hyperactivation of the sympathetic nervous system is not a recognized condition in itself , but it is a component of a number of conditions , as well as a possible consequence of taking sympathomimetic drugs . It causes a distinctive set of symptoms including aches and pains , rapid heartbeat , elevated blood pressure , sweating , palpitations , anxiety , headache , paleness , and a drop in blood glucose . If sympathetic activity is elevated for an extended time , it can cause weight loss and other stress @-@ related body changes . 
