Sleep Stages: Two Stages And Their Sub-categories

Knowing the different sleep stages help you appreciate why insomnia usually becomes a problem. Learn more about NREM and REM sleep as you move along.

The different stages of sleep describe what an individual is undergoing while in this resting state. These two stages may actually take intervals and have alternates at times. Aside from the major classes, there are also sub-categories under each sleep stage. Find out more about what we are talking about to see where insomnia comes in.

Non-rapid eye movement (NREM) and rapid eye movement (REM) are two of the sleep stages. Both takes several cycles each night to complete a person’s sleeping activity. One whole cycle of NREM to REM sleep usually takes one hour and 30 minutes. So if you sleep around 6 hours during nighttime, then you have completed around four cycles.

The different sleep stages

If you want to learn more about what takes place during your sleeping hours, pay attention to the different stages of sleep. NREM sleep has its own stages from first to the fourth while REM sleep follows the four stages. Here are the sleep stages:

• Stage I NREM Sleep. This is regarded as the transition from the time you get yourself to sleep up to the time you have fallen asleep. It is during this time when you relax your tensed muscles. This stage is said to constitute 5 to 10 percent of the total sleep time. During this period, you are still on a stage of light sleep.

• Stage II NREM Sleep. This comprises bulk of the sleeping hours – about 40 to 50 percent at the most. It is during this stage when the brain seems to stop doing its activities although not really inhibiting its works. As the brain slows down, the eye movement also stops. Rapid waves are also present during this span.

• Stage III NREM Sleep. During this stage, delta waves are apparent. These are slower waves than those represented in the second stage. The delta waves are also combined with smaller yet quicker waves. It is actually the start of deep sleep.

• Stage IV NREM Sleep. Stage IV concentrates more on delta waves - that is without the interception of the other waves present in stage III. Together with Stage III, this is around 20% of the entire sleep duration. It also stops all the movement pertaining not only to the eyes but also that of the muscles. Since individuals are placed under deep sleep during these last two stages, there is a great chance that waking these people up is too difficult during these moments.

• REM Sleep. This is the stage of sleep which is commonly associated with a person’s capability to dream. During this 20 to 25% stage, the eye moves rapidly and the heart rate is faster than usual. Blood pressure even rises and the breathing speeds up.

As you know how your sleep progresses, you are able to appreciate why insomnia becomes a problem as well. Once stage I does not progress to stage II, the insomnia problem may become prevalent. It is therefore important to take note of the activities that usually happen before these sleep stages.

Tags: insomnia, NREM sleep, REM sleep, sleep, sleep stages

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