Persistent fatigue occurs in more than 90 percent of people with fibromyalgia. A part of the tiredness is due to lack of Non-REM sleep in Fibro patients. Most people complain of unusually light, unrefreshing, or nonrestorative sleep. Difficulties falling asleep, awakening repeatedly during the night, and feeling exhausted upon awakening are also common problems. The neurotransmitter imbalance is the main cause of persistent tiredness in Fibro patients.