Patients with fibromyalgia were found to have an impaired ability to activate the hypothalamic pituitary portion of the hypothalamic-pituitary-adrenal axis as well as the sympathic-adrenal system, leading to reduced corticotrophin (ACTH) and epinephrine (adrenaline) responses to hypoglycemia. The impairement of these neuroendocrine systems in fibromyalgica may even more explain the overlap in signs and symptoms between fibromyalgia and hypoglycemia.