Sleep deprivation intensifies our sensitivity to pain
While it is known that pain can lead to sleepless nights, scientists at UC Berkeley wanted to know how a lack of sleep may affect pain. The researchers identified neural glitches in the brain among sleep-deprived individuals that make pain more intense and more persistent.
In 2015, a survey by the National Sleep Foundation found that two out of three patients with chronic pain suffer from frequent sleep disruptions. The findings of the current study help to explain the overlapping epidemics of sleep loss and chronic pain, as well as opioid addiction.
“If poor sleep intensifies our sensitivity to pain, as this study demonstrates, then sleep must be placed much closer to the center of patient care, especially in hospital wards,” said study senior author Professor Matthew Walker.
The investigation, which was led by UC Berkeley Ph.D. student Adam Krause, was focused on two dozen healthy young adults. The team scanned their brain activity while uncomfortable levels of heat were applied to their legs.
When the individuals were sleep deprived, the neural mechanisms that respond to pain signals and activate natural pain relief were disrupted. Beyond confirming their theory that sleep deprivation intensifies pain, the researchers were surprised to discover weakened activity in the nucleus accumbens, a region of the brain’s reward system that increases dopamine levels to relieve pain.
“Sleep loss not only amplifies the pain-sensing regions in the brain, but blocks the natural analgesia centers, too,” said Professor Walker.
The researchers also conducted a survey of more than 230 American adults of all ages. The participants reported on their nightly hours of sleep as well as their day-to-day pain levels over the course of a few days. The results showed that even minor shifts in sleep and wake patterns coincided with changes in sensitivity to pain.
“The results clearly show that even very subtle changes in nightly sleep – reductions that many of us think little of in terms of consequences – have a clear impact on your next-day pain burden,” said Krause.
Professor Walker explained, “The optimistic takeaway here is that sleep is a natural analgesic that can help manage and lower pain. Yet ironically, one environment where people are in the most pain is the worst place for sleep – the noisy hospital ward.”
“Our findings suggest that patient care would be markedly improved, and hospital beds cleared sooner, if uninterrupted sleep were embraced as an integral component of healthcare management.”
Professor Walker plans to work with hospitals to create more sleep-friendly inpatient facilities.
The study is published in the Journal of Neuroscience.