People with insomnia have a lower tolerance to pain, according to a new study conducted in Norway.
The study included more than ten thousand adults from a large, ongoing Norwegian health study. Subjects were asked about various types of sleep impairment, including insomnia, total sleep time, and how long it took them to fall asleep. Each subject underwent a standard test of pain sensitivity in which subjects are asked to keep their hand submerged in a cold water bath.
Overall, 32 percent of participants were able to keep their hand in the cold water throughout the 106-second test. Participants with insomnia were 12-percent more likely to take their hand out early.
Pain sensitivity increased with both the frequency and severity of insomnia. For example, compared with individuals who reported no insomnia, rates of reduced pain tolerance were 52-percent higher for subjects reporting insomnia more than once weekly versus 24-percent for those with insomnia once monthly.
The study was published in Pain, the official publication of the International Association for the Study of Pain.