In a study where the sleep patterns of healthy volunteers were deliberately disrupted to make them similar to those of people with CFS, they developed symptoms similar to those of CFS, including feeling unrefreshed and physically weak, sleepiness, poor concentration and muscle aches. However, when they were allowed to sleep undisturbed, their symptoms subsided. This study indicates that a disturbed sleep pattern can cause some symptoms of CFS, but that these symptoms are reversible.
