Patterns of Hypocapnia on Tilt in Patients with Fibromyalgia, Chronic Fatigue Syndrome, Nonspecific Dizziness, and Neurally Mediated Syncope

Hyperventilation appears to be the major abnormal response to postural challenge in sustained hypocapnia but possibly merely an epiphenomenon in hypotensive-hypocapnic events. Our study does not support an essential role for hypocapnia in NMS or in postural symptoms associated with POTS. Because unrecognized hypocapnia is common in CFS, fibromyalgia, and nonspecific dizziness, capnography should be a part of the evaluation of patients with such conditions.