Insomniacs have lower pain threshold

A new study has reported that people with insomnia and other sleep related problems have increased sensitivity to pain.

The study also found that effect on pain tolerance appears strongest in people who suffer from both insomnia and chronic pain and that these people may benefit most from treatments targeting both ailments.

The study was conducted on more than 10,400 adults from an ongoing Norwegian health study. Each adult was subjected to a standard test of pain sensitivity, the cold pressor test, in which subjects are asked to keep their hand submerged in a cold water bath.

The results showed that pain sensitivity increased with both the frequency and severity of insomnia. For example, compared with subjects 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.

It was also found that sleep latency affected pain sensitivity, although this did not affect total sleep time. Age and Sex also had no effect on the relationship formed, but it was found that psychological distress had a small but significant effect on the relationship.

Patients reporting high problems with both insomnia and chronic pain were more than twice as likely to have reduced tolerance to pain and many patients who experience sleep impairment and pain face high costs and personal difficulties.

Lead researcher Borge Sivertsen said that while there is clearly a strong relationship between pain and sleep, such that insomnia increases both the likelihood and severity of clinical pain, but it is not clear exactly why this is so.

Meanwhile, the study clearly shows the need for efforts to improve sleep among patients with chronic pain and vice versa. Cognitive-behavioral therapy approaches have proved effective for pain problems and insomnia individually.

The study is published in PAIN.