Imparied Sleep and Pain Sensitivity
A recent study in PAIN, the official publication of the International Association for the Study of Pain has demonstrated that in people who suffer from both insomnia and chronic pain there is a strong negative effect on pain tolerance and that these individuals may benefit from treatments targeting both conditions.
The study included more than 10,400 adults from a large, ongoing Norwegian health study. Self-reported sleep measures provided information on, sleep duration, sleep onset latency, and sleep efficiency, as well as frequency and severity of insomnia. The main outcome measure was pain sensitivity tests, including assessment of cold-pressor pain tolerance. The researchers found that all sleep parameters, except sleep duration, were significantly associated with reduced pain tolerance. The study also looked at other factors potentially affecting sleep impairment and pain perception, including chronic (persistent or recurring) pain and psychological distress (such as depression and anxiety).
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. Pain sensitivity was also linked to sleep latency, although not to total sleep time. The relationships were unchanged after adjustment for age and sex. The effect was smaller, but still significant, after further adjustment for psychological distress.