Extended Sleep Increases Daytime Alertness and Reduces Pain Sensitivity

Sleep is one of the critical determinants of health and well-being. What really counts is not the number of hours spent in sleeping but it is the quality of those hours of sleep. Sleep disturbance is one of the most common problems faced by chronic pain patients.

There are many reasons for a disturbed sleep pattern. What cannot be denied is that it takes a heavy toll on physical and mental health. But a new study holds out hope for sleep sufferers.

According to a new American study, extended night sleep in mildly sleepy healthy adults increases their daytime alertness and also reduces pain sensitivity.

"Our results suggest the importance of adequate sleep in various chronic pain conditions or in preparation for elective surgical procedures," said Timothy Roehrs, PhD, of the Sleep Disorders and Research Center at Henry Ford Hospital in Detroit and also the study's principal investigator and lead author. "We were surprised by the magnitude of the reduction in pain sensitivity, when compared to the reduction produced by taking codeine."

In order to proceed with their finding, the researchers conducted a study on 18 healthy, pain free, sleepy volunteers. These volunteers were assigned to four nights of either maintaining their habitual sleep time or extending their sleep time by spending 10 hours in bed per night. 

By using the multiple sleep latency test (MSLT) the researchers measured the objective daytime sleepiness and the pain sensitivity was assessed using a radiant heat stimulus.

On conducting this experiment, researchers learnt that the extended sleep group slept 1.8 hours more per night.

This nightly increase in sleep time during the four experimental nights was correlated with increased daytime alertness, which was associated with less pain sensitivity.

In the extended sleep group, the extent of time before participants removed their finger from a radiant heat source increased by 25 percent, reflecting a reduction in pain sensitivity. 

According to the researchers, the magnitude of this increase in finger withdrawal latency is greater than the effect found in a previous study of 60 mg of codeine.

This is the first study which highlights that extended sleep in mildly, chronically sleep deprived volunteers reduces their pain sensitivity.

The results, combined with data from previous research, suggest that increased pain sensitivity in sleepy individuals is the result of their underlying sleepiness.

The study appears in the December issue of the peer-review, scientific journal SLEEP, which is published online by the Associated Professional Sleep Societies LLC, a joint venture of the American Academy of Sleep Medicine and the Sleep Research Society.