According to the Mayo Clinic, “Fibromyalgia is a disorder characterized by widespread musculoskeletal pain accompanied by fatigue, sleep, memory and mood issues.”
In the book, The Promise of Sleep, it also mentions that …
“There is always daytime fatigue and very commonly difficulty falling asleep and staying asleep”.
While it may seem logical that pain can affect sleep, there may be something more. The book says that a sleep test would often show irregular alpha-delta sleep.
The reason why is not entirely clear.