Pain and a lack of sleep affect a lot of people, often at the same time. Yet scientists are still sorting out the relationship between the two.
Sure, you can see where that pain in your back can keep you up at night. Long-lasting, or chronic, pain can lead to problems like anxiety and depression, which can also cause sleep disorders.
But does it work the other way around? Does poor sleep lead to more pain?
Or with a glass-half-full approach: Could better sleep lead to less pain?
“In the big picture, what we know is that sleep and pain are strongly related,” says Patrick Finan, PhD, an assistant professor of psychiatry and behavioral sciences with John Hopkins Medicine in Baltimore. “Increases in sleep problems tend to beget increases in pain problems, and vice versa.”
Untangling Sleep and Pain
The pain-sleep relationship is complicated. One big reason: Both pain and sleep are hard to measure. Everyone perceives them differently.
Take sleep, for example. Experts say that most people need at least 7 hours of sleep a night. But not everyone does. Sleep needs differ from person to person.
Quality of sleep is highly personal as well. What may be a good 8 hours for you might be a tossing, turning, staring-at-the-ceiling lousy night’s rest for your partner.
Pain makes things even more complicated. A 2015 poll from the National Sleep Foundation found that 65% of people without pain say they get good or very good sleep. But for those with acute pain, it’s just 46%; with longer-term pain, only 36%.
That backache keeping you up is one thing. But restless nights can also lead to more pain. How does that work?
“What the experimental studies suggest is that when you don’t sleep well you have a heightened sensitivity to pain,” says Kristen Knutson, PhD, a biomedical anthropologist at the University of Chicago. “Healthy people, if they’re subjected to sleep restrictions or impaired sleep, they report greater pain sensitivity.”
It’s a “vicious cycle,” Knutson says, with pain leading to a lack of sleep and that lack of sleep leading to a greater sensitivity to pain. And it’s a cycle that’s hard to break.