Tuesday, May 5, 2009

* Sleep *

i read this article this morning!! it's important to share v u all.... muz get a nice sleep!!

Sleep stages: the sleep cycle

Understanding sleep stages and the sleep cycle can help you get better sleep. Your sleep is regulated by an internal body clock, sensitive to light, time of day and other cues for sleep and awakening. When you fall asleep, your sleep goes in cycles throughout the night, moving back and forth between deep restorative sleep and more alert stages and dreaming. As the night progresses, you spend more time in dream sleep and lighter sleep.

There are two main types of sleep. REM (Rapid Eye Movement) sleep is when you do most active dreaming. Your eyes actually move back and forth during this stage, which is why it is called REM sleep. Non-REM (NREM) sleep consists of four stages of deeper and deeper sleep. Each sleep stage is important for overall quality sleep, but deep sleep and REM sleep are especially vital.

Sleep stages and brain activity

Why we sleep (Scientific American) provides a detailed description of brain activity during the stages of sleep and wakefulness. Includes excellent diagrams.

Stage 1 (Drowsiness) - Stage 1 lasts just five or ten minutes. Eyes move slowly under the eyelids, muscle activity slows down, and you are easily awakened.

Stage 2 (Light Sleep)
- Eye movements stop, heart rate slows, and body temperature decreases.

Stages 3 & 4 (Deep Sleep)
- You’re difficult to awaken, and if you are awakened, you do not adjust immediately and often feel groggy and disoriented for several minutes. Deep sleep allows the brain to go on a little vacation needed to restore the energy we expend during our waking hours. Blood flow decreases to the brain in this stage, and redirects itself towards the muscles, restoring physical energy. Research also shows that immune functions increase during deep sleep.

REM sleep (Dream Sleep)
– At about 70 to 90 minutes into your sleep cycle, you enter REM sleep. You usually have three to five REM episodes per night. This stage is associated with processing emotions, retaining memories and relieving stress. Breathing is rapid, irregular and shallow, the heart rate increases, blood pressure rises, males may have penile erections, and females may have clitoral enlargement.

How we fall asleep

How do our bodies know when it is time to sleep? We all have an internal circadian clock that provides cues for when it is time to sleep and time to wake. This clock is sensitive to light and time of day, which is why having a good bedtime routine and a quiet dark place to sleep is so important. At the same time, a chemical messenger called adenosine builds up during the day as our bodies are busy using energy. The more adenosine builds up in the brain, the sleepier you will feel. Adenosine combined with the circadian clock sends a powerful message of sleepiness to your body.

Importance of deep sleep and REM sleep

Deep Sleep
Each stage of sleep offers benefits to the sleeper. However, deep sleep is perhaps the most vital stage. It is the first stage that the brain attempts to recover when sleep deprived, and the strongest effects of sleep deprivation are from inadequate deep sleep. What might disrupt deep sleep? If you are caring for someone around the clock, whether it is a small infant or an elderly relative with a serious illness, you might need to attend to them suddenly in the middle of the night. Loud noise outside or inside the home might wake you. If you work the night shift, sleeping during the day may be difficult, due to light and excess noise during the day. Substances like alcohol and nicotine also disrupt deep sleep.
Maximize your deep sleep. Make sure your sleep environment is as comfortable as possible and minimize outside noise. If you are being awakened as a caregiver, make sure that you get some time of uninterrupted sleep, especially if you have had some unusually disruptive
nights. Don’t be afraid to ask for help.

REM sleep
REM sleep, or dream sleep, is essential to our minds for processing and consolidating emotions, memories and stress. It is also thought to be vital to learning, stimulating the brain regions used in learning and developing new skills. Most of dreaming occurs during REM sleep, although it can happen during other sleep stages as well. There are different theories as to why you dream. Freud thought that dreams were the processing of unconscious desires. Today, researchers wonder if it may be the brain’s way of processing random fragments of information received during the day. Much of dreaming is still a mystery. If REM sleep is disrupted one night, your body will go through more REM the next to catch up on this sleep stage.

Getting more REM sleep
Studies have shown that better REM sleep helps boost your mood during the day. How can you get more REM sleep? One simple way is to try to sleep a little more in the morning. As your sleep cycles through the night, it starts with longer periods of deep sleep. By the morning, the REM sleep stage is longer. Try sleeping an extra half hour to hour and see if your mood improves.
Improving your overall sleep will also increase your REM sleep. If your body is deprived of deep sleep, it will try to make that up first- at the expense of REM sleep.


sushi^^ said...

wow...now oni i noe there r so many diff stages of sleeping... very de informative...^^

Cassandra said...

yup... so muz really sleep well everyday!!

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