01 December 2012

Increasing Sleep Time Increases Daytime Alertness and Reduces Pain Sensitivity

Researchers find that having extended nightly sleep can increase daytime alertness and reduces pain sensitivity.

Sleep is a very important regular activity for the body. This is the time when the body gets some rest from physical activity while the internal systems starts to "clean up".

Healthy sleep contributes to a lot of positive factors. Various studies on sleep shows that it can relieve the person from emotional stress, it can aid in healtyh weight loss, and it can even improve the body's insulin resistance for diabetics.

There are two types of sleep. REM (Rapid Eye Movement) sleep and and NREM (Non-Rapid Eye Movement) sleep.

But aside from the two type of sleep, there are also five stages of sleep. These five stages are characterized by the production of waves by the brain starting with beta waves. As one goes deeper into sleep, the brain starts producing other waves such as delta waves and theta waves.

The first stage of sleep marking the beginning of the sleep cycle lasts about five to ten minutes. It is light sleep that connects wakefulness and sleep. During this time, the brain produces slow waves with high amplitude called theta waves.

The second stage of sleep is marked by the brain producing rapid, rhythmic brain activity called sleep spindles. The duration of this stage is about twenty minutes and is the time when the body temperature and heart rate begins to slow down.

During the third stage, the brain starts producing deep and slow delta waves. This marks the transition between light sleep and very deep sleep.

The fourth stage of sleep is known as the delta sleep. Just like the third stage, delta waves are produced but the person is in a deep sleep that lasts for thirty minutes.

The last stage of sleep is when REM sleep happens. It is characterized by eye movement, increased respiration rate and increased brain activity. The brain and body systems are active but the muscular system is relaxed. This is also the stage when dreams start to occur.

Video: How to Get Good Sleep

The stages of sleep does not happen in order. The sequence starts from the first stage to the fourth stage. But afterwards, it cycles back to the second stage until the person goes into REM sleep. After a few minutes, the sleep cycle then goes back to stage two.

REM sleep occurs for about 90 minutes in total.

Link Between Extended Nightly Sleep and Chronic Pain Conditions

A new study suggests that extending nightly sleep in mildly sleepy, healthy adults increases daytime alertness and 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, 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."

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.

According to the authors, this is the first study to show 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.


American Academy of Sleep Medicine
Stages of Sleep
Continuous Sleep Favorable In Long Term Memory Consolidation and Enhancement
Healthy Adequate Sleep Contribute To Weight Loss Programs
Dream Sleep Relieves Stress from Emotional Pain
7 Hours is Optimal Sleep For High School Students Before A Test
Teens Getting Seven Hours Of Sleep Improves Insulin Resistance By 9%
Sleep Patterns Inconsistent With Biological Clock May Lead to Diabetes and Obesity
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