The Sleep/Pain Cycle

Achieving restful sleep can be particularly difficult for people like Applegate who have chronic pain. “Pain is a lump of coal under your mattress,” says Spielman. “Even when you’re asleep, the mind can register pain.”

People may notice obvious signs of pain and sleep problems, such as not being able to fall asleep or waking up frequently due to discomfort, says Michael Smith, PhD, director of the sleep psychophysiology laboratory at Johns Hopkins University in Baltimore. Or – and Smith believes this may be more disabling – they have disruptions in the sleep cycle itself so that they sleep but don’t get enough deep sleep. They may be aroused during sleep and pushed from deep sleep into a lighter stage without ever knowing it. “Their deeper sleep is disrupted by arousals or outright awakenings,” Smith says. “They may sleep 10 hours but feel groggy and unrefreshed the next day.”

That also may be the case for people with fibromyalgia, who tend to have abnormalities in deeper-stage sleep. Researchers have explored whether sleep disorders cause the pain of fibromyalgia or vice versa, but it’s still not clear.

Inflammation, pain and the immune system all appear to be impacted to some degree. In a 2006 study by the University of California, Los Angeles, researchers evaluated the effects of sleep deprivation on 30 healthy adults. After only one night, participants who were kept awake from 11 p.m. to 3 a.m. experienced an increase in inflammatory chemicals the body produces in autoimmune diseases, such as rheumatoid arthritis (RA).

When you can’t sleep because of pain, the process can become a seemingly endless loop. A recent study by Smith found that fragmented sleep resulted in both increased pain sensitivity and more spontaneous pain. Bernard Rubin, chief of rheumatology at the University of North Texas Health Science Center in Fort Worth, says, “It gets to be a vicious cycle. If you don’t sleep well, pain is accentuated.”

That’s because sleep doesn’t just reboot your system, refreshing your body and mind for the next day. It also helps repair your body.

Growth hormone, which the body releases most often in our deepest stages of sleep, helps heal tiny muscle tears that occur naturally during the course of the day, says Daniel Clauw, MD, a rheumatologist and director of the Chronic Pain and Fatigue Research Center at the University of Michigan. As we age, the amount of growth hormone that is secreted declines, along with the amount of time we spend in deep sleep, although scientists aren’t sure if one causes the other. But if your deep sleep is disrupted, your body may not secrete enough growth hormone to heal itself. 

Your waistline may also be at risk if you can’t sleep. A recently published analysis of the Nurses’ Health Study, involving data from nearly 70,000 women, found that those who slept no more than six hours nightly faced a 12 percent higher likelihood of gaining 33 pounds during the 16-year study. The risk jumped to 32 percent if they slept five hours or less. Because the shortchanged sleepers didn’t consume any more calories, the cause remains unknown, according to Sanjay Patel, MD, an assistant professor of medicine at Case Western Reserve University in Cleveland, who led the study. One theory is that sleep deprivation may alter the body’s metabolism.

Ongoing sleep deprivation has also been linked to chronic health problems such as diabetes or hypertension, although the specific mechanisms remain unclear, says Dr. Clauw. “There’s almost no biological function that sleep doesn’t affect in a fairly profound way,” he says. “We used to think of poor sleep as a nuisance, but it’s a legitimate health problem.”