To be less sensitive to pain, you might want to hit the hay.
A small new study links sleeping longer at night with decreased pain sensitivity and more alertness during the day.
"Our results suggest the importance of adequate sleep in various chronic pain conditions or in preparation for elective surgical procedures," study researcher Timothy Roehrs, Ph.D., of Henry Ford Hospital. "We were surprised by the magnitude of the reduction in pain sensitivity, when compared to the reduction produced by taking codeine."
The study included 18 people between ages 21 and 35 who were healthy, free of pain and sleep-deprived (their sleepiness was determined by using an assessment called the Multiple Sleep Latency Test). Researchers had some of the participants spend four nights going to bed at their normal time, and had the others go to bed for 10 hours each night. The researchers found that the group who was instructed to spend 10 hours each night in bed slept for 1.8 hours longer than those who were allowed to go to bed at their usual time.
The researchers tested the study participants' pain tolerance by having them do a radiant heat stimulus test, where they had to leave their finger as long as possible by a source of heat. They found that those who were instructed to stay in bed longer were able to keep their fingers by the heat source 25 percent longer than those who got less sleep.
The study authors noted that this improvement in decreased pain sensitivity is even greater than that experienced in a past study that examined the effects of 60 milligrams of codeine on pain sensitivity.
Researchers speculated in the study that this pain sensitivity effect may have to do with cytokines, which are an important player in inflammation. "Pain is a hallmark of inflammation and studies have shown that sleep disruption and sleep restriction activate the pro-inflammatory cytokines, interleukin -6 and tumor necrosis factor alpha," the researchers wrote in the SLEEP study.