Impaired sleep associated with chronic pain tolerance

A new study has reported that people with insomnia have showed increased sensitivity to pain. Pain sensitivity was also linked to the amount of time it took to get to sleep. The study was published in the journal Pain.

"The need to improve sleep among chronic pain patients, and vice versa, is evident," said Borge Sivertsen of the Norwegian Institute of Public Health in Bergen.

The study was conducted on more than 10,400 adults from an ongoing Norwegian health study. Out of all of the participants, 10.5 percent had what the researchers considered an insomnia disorder.  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 42 percent of patients who had insomnia took their hands out of the water before the 106 seconds were up, whereas only 31 percent of all of the participants did so. It showed increased sensitivity to pain was greater in those with severe insomnia.
 
The link between sleep problems and chronic pain appeared especially pronounced, according to the study. The patients with both severe insomnia and chronic pain were more than twice as likely to take their hands out of the water early as participants who had neither condition. But the total amount of time that people spent sleeping showed no effect on their pain tolerance. Future research should look into not only clinical implications, but also the role of neurotransmitters in the co-occurrence of sleep disorders and pain, the authors said.

By Lizitha