Extended Sleep Increases Alertness and Reduces Pain Sensitivity

Lots of research has been carried out concerning sleep and more is still being done. The various results we’ve had always point to the fact that adequate sleep is essential for us to live a healthy life. We know of the importance of sleep when it comes to learning and memory: sleep helps the brain commit new information to memory. People who’d slept after learning a task did better on tests later. Sleep deprivation may cause weight gain by affecting the way our bodies process and store carbohydrates. We know that the troubles of not having adequate sleep can affect our safety, mood and increase our susceptibility to diseases.

A new study however, has brought a new dimension to the sleep and healthiness issue by observing for the first time the relationship between amount of night-time sleep to daytime alertness and pain sensitivity. The study suggests that extending nightly sleep in mildly sleepy, healthy adults increases daytime alertness and reduces pain sensitivity. The research suggests how important it is for people with chronic pain conditions and even those going for a surgical operation to have adequate sleep.

The study, appearing in the December issue of the journal SLEEP, involved 18 healthy, pain-free, sleepy volunteers. They were randomly assigned to four nights of either maintaining their habitual sleep time or extending their sleep time by spending 10 hours in bed per night. Objective daytime sleepiness was measured using the multiple sleep latency test (MSLT), and pain sensitivity was assessed using a radiant heat stimulus.

Results show that the extended sleep group slept 1.8 hours more per night than the habitual sleep group. 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 length of time before participants removed their finger from a radiant heat source increased by 25 percent, reflecting a reduction in pain sensitivity. The authors report that the magnitude of this increase in finger withdrawal latency is greater than the effect found in a previous study of 60 mg of codeine.

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