Sleep Disturbance and the Experience of Pain

It is not hard to understand that pain can make sleep difficult, but how does sleep disturbance drive pain sensitivity?

Experts agree evidence is ample to support a reciprocal relationship between pain and sleep, and there’s a growing consensus that sleep disturbance is more predictive of pain than pain is of sleep disturbance.

“There are plenty of studies, but any patient with chronic pain, or any doctor who treats them, can tell you that sleep is analgesic,” said Timothy Roehrs, PhD, director of research at the Sleep Disorders and Research Center at the Henry Ford Health System in Detroit.

As many as 50% of people with insomnia also have chronic pain, and sleep complaints are present in close to 90% of chronic pain disorders.1

“All four options of reciprocity have been consistently shown. Less sleep leads to more pain. More sleep leads to less pain. More pain leads to less sleep, and less pain leads to more sleep,” said Thomas Roth, PhD, founder and director of the Sleep Disorders and Research Center.

How Sleep Increases Pain Sensitivity

It is not hard to understand that pain can make sleep difficult, but how does sleep disturbance drive pain sensitivity?

In a 2012 study published in the journal Sleep, Roehrs and Roth were able to show that extending sleep in healthy volunteers for just 1.8 hours per night over four nights reduced pain sensitivity (as measured by finger withdrawal from radiant heat).2

“In another study, we were able to show that reducing the fragmented sleep that occurs in sleep apnea reduced pain sensitivity by about 30%,” Roehrs said. “We treated sleep apnea patients with continuous positive airway pressure (CPAP). This reduced apnea events from 50 events per hour to just two events. After taking patients off CPAP for just two nights, both apnea events and pain sensitivity increased.”

Three large longitudinal studies have shown that insomnia increases the risk for exacerbation of tension headaches and onset of new tension headaches.1 “Research has shown that sleep disturbance triggers all kinds of pain, including dental pain, fibromyalgia, and trauma,” said Roth.

A host of recent experimental sleep deprivation studies have shown that even a single night of sleep disturbance can increase both clinical pain and experimentally induced pain.1

The mechanism by which sleep drives pain is still unsettled. Proposed theories include dysregulation of endogenous opiate systems, alteration in dopaminergic signaling, and activation of proinflammatory cytokines.2