Dr Michael Breus explores the research into the effects of CFS on sleep. Excerpt from his article:

Disrupted sleep is a hallmark of chronic fatigue syndrome. Chronic fatigue is associated with a range of sleep problems, including:

• Excessive daytime sleepiness
• Non-restorative sleep (waking feeling tired even after sufficient or prolonged periods of rest)
• Difficulty falling asleep and staying asleep
• Sleep disorders such as obstructive sleep apnea, insomnia, and narcolepsy

Despite the frequency with which people with chronic fatigue syndrome experience sleep disturbances, the connection between sleep and chronic fatigue—like so much else about the disorder—is not well understood.

Researchers at Australia’s Victoria University have conducted a review of research related to sleep and chronic fatigue. Their analysis sheds some light on possible reasons for poor sleep among patients with chronic fatigue.

• Sleep complaints are common among chronic fatigue patients, but there is no single or typical sleep experience for people with this disorder. For the past two decades, research has shown high levels of sleep disorders among adults with this condition:
• Several studies, including this one, have found that more than half of chronic fatigue patients have some type of sleep disorder
• This study showed chronic fatigue patients experience greater levels of disrupted sleep than patients with multiple sclerosis
• More than 50% of chronic fatigue patients in this study had obstructive sleep apnea or sleep-related movement disorders, such as restless leg syndrome
• A similar study showed 46% of chronic fatigue patients suffering from obstructive sleep apnea
• [Another] large, population-based study showed nearly 80% of chronic fatigue patients experienced un-refreshing sleep, and 20% had obstructive sleep apnea or narcolepsy

An important area of research into the connection between sleep and chronic fatigue looks at the role of pain. The physical pain associated with chronic fatigue may be a significant factor in the sleep problems experienced by people with chronic fatigue. We know that pain and sleep influence each other in multiple ways. Pain can make sleep difficult to achieve and sustain. Lack of sleep, in turn, can make us more sensitive to pain. Studies like this one have shown that pain causes chronic fatigue patients to wake more often throughout the night than either healthy people or those with depression. And this study found that disruption to slow wave sleep in healthy people triggered physical pain and fatigue similar to people with chronic fatigue syndrome. As researchers themselves note, the role of muscle pain in sleep disorders among chronic fatigue sufferers is an area of research that warrants more attention and further study.

There’s another body of research that suggests that people with chronic fatigue experience changes to their sleep cycles that could result in less restorative sleep. Studies have shown that people with chronic fatigue may spend less time in slow wave sleep than healthy people. Slow wave sleep occurs during the sleep stages 3 and 4, and is the most restorative sleep we can experience. Studies have shown that chronic fatigue patients spend a reduced amount of time in slow wave sleep and in REM sleep than healthy people. To date, there is less evidence for the reduction in REM sleep than in slow wave sleep. The cause of this disturbance to sleep cycles is unclear. However, there is evidence of a possible link between systematic inflammation and disruptions to sleep cycles, particularly to time spent in slow wave sleep. Systemic inflammation in the body is common among chronic fatigue patients, and may play a role in the persistent problem of non-refreshing sleep.

Still another area of study suggests that changes to the body’s nervous system activity may play a role in the sleep disruptions experienced by people with chronic fatigue. Chronic fatigue patients experience alterations to the functioning of their nervous systems during waking hours, and these can continue during sleep. Several studies have shown that chronic fatigue patients are more likely to experience disruptions to normal nervous system activity during sleep, and this may be affecting the quality of sleep they experience.

Chronic Fatigue Syndrome: How Does It Affect Sleep? Dr Michael J Breus

Sleep abnormalities in chronic fatigue syndrome/myalgic encephalomyelitis: a review   Dr Melinda L. Jackson, Dr Dorothy Bruck, School of Social Sciences and Psychology, Victoria University, Victoria, Australia