It’s no secret that sleep is one of the most important activities for good health. Although, the biological purpose behind sleep remains a mystery, research shows that a chronic lack of sleep, or getting poor quality sleep, increases the risk of disorders including high blood pressure, cardiovascular disease, diabetes, depression, and obesity.

Let me pose this question, Is the amount you sleep you get the most important thing in regards to your sleeping pattern? or maybe, is getting eight hours of sleep better than getting 6 hours of sleep?

To answer that question we must explore the different stages of sleep, what they are and what happens during each stage. 

There are two basic types of sleep:  rapid eye movement (REM) sleep and non-REM sleep (which has three different stages). 

Non-REM sleep happens first and includes three stages. stage N1, stage N2, and stage N3. Older classification had four stages of NREM sleep. Now however, NREM stage 3 and NREM stage 4 are now combined as stage N3.The last stage of non-REM sleep is when you sleep deeply.

REM sleep happens about an hour to an hour and a half after falling asleep. REM sleep is when you tend to have vivid dreams.

Each sleep stage has a unique function and role in maintaining your brain’s overall cognitive performance while others are also associated with physical repairs that keep you healthy and get you ready for the next day.

NREM Stage N1

This stage of non-REM sleep is the typical transition from wakefulness to sleep and generally lasts only a few minutes. Stage N1 is the lightest stage of sleep. At this time, the brain moves away from using beta waves—small and fast brainwaves that mean the brain is active and engaged to alpha waves. Patients awakened from it usually don’t perceive that they were actually asleep.

NREM Stage N2

This next stage of non-REM sleep comprises the largest percentage of total sleep time and is considered a lighter stage of sleep from which you can be awakened easily. This is the stage before you enter deep sleep.

The brain begins to produce bursts of rapid, rhythmic brain wave activity, which are known as sleep spindles. They are thought to be a feature of memory consolidation—when your brain gathers, processes, and filters new memories you acquired the previous day.5

While this is occurring, your body slows down in preparation for NREM stage 3 sleep and REM sleep—the deep sleep stages when the brain and body repairs, restores, and resets for the coming day

NREM Stage N3

This final stage of non-REM sleep is the deepest sleep stage. Deep, slow brain waves known as delta waves begin to emerge during NREM stage 3 sleep—a stage that is also referred to as delta sleep. This is a period of deep sleep where any noises or activity in the environment may fail to wake the sleeping person.

Getting enough NREM stage 3 sleep allows you to feel refreshed the next day.

It is during this deep sleep stage that your body starts its physical repairs.

Meanwhile, your brain consolidates declarative memories—for example, general knowledge, facts or statistics, personal experiences, and other things you have learned.7

REM Stage R

There are two phases of REM sleep: phasic and tonic. Phasic REM sleep contains bursts of rapid eye movements, while tonic REM sleep does not.

While your brain is aroused with mental activities during REM sleep, the fourth sleep stage, your voluntary muscles become immobilized.

It’s in this stage that your brain’s activity most closely resembles its activity during waking hours. However, your body is temporarily paralyzed—a good thing, as it prevents you from acting out your dreams.1

Stage R occurs about 90 minutes after you fall asleep, and is the primary “dreaming” stage of sleep. Stage R sleep lasts roughly 10 minutes the first time, increasing with each REM cycle. The final cycle of stage R may last roughly between 30 to 60 minutes.

Like stage 3, memory consolidation also happens during REM sleep. However, it is thought that REM sleep is when emotions and emotional memories are processed and stored.8

Your brain also uses this time to cement information into memory, making it an important stage for learning.

When you fall asleep at night, you cycle through all of these stages of sleep multiple times — roughly every 90 minutes or so.

It’s important to realize that sleep does not progress through the four stages in perfect sequence.

When you have a full night of uninterrupted sleep, the stages progress as follows:

Sleep begins with NREM stage 1 sleep.

NREM stage 1 progresses into NREM stage 2.

NREM stage 2 is followed by NREM stage 3.

NREM stage 2 is then repeated.

Finally, you are in REM sleep.

Once REM sleep is over, the body usually returns to NREM stage 2 before beginning the cycle all over again.

Time spent in each stage changes throughout the night as the cycle repeats (about four to five times total).

Why this is important is because if the sleep cycle process is interrupted, such as when we’re woken up during the night, the process starts over again. As a result, when you experience interrupted sleep, you miss out on REM most of all and without sufficient REM, your cognitive performance and emotional wellbeing suffer. The impact this has is that after a night of interrupted sleep, your mental sharpness, focus, and attention span all suffer. You may have difficulty concentrating, and your reaction time is slower than usual. You can have trouble learning the things you experienced the day before. We have less capacity to process and remember new information with interrupted sleep. Additionally, during sleep, your brain flushes away toxins like amyloid-beta, a type of protein that’s linked to Alzheimer’s disease. In studies of people who regularly experience interrupted sleep, brain imaging shows a build up of these proteins.

 

So with all this, quality beats quantity. To receive the benefits of a good night’s sleep, the amount of time you sleep uninterrupted can be more important than the total amount of time you sleep overall. So just because you spend 10 hours in bed, doesn’t mean that it’s better than 7 hours of uninterrupted sleep.

My advice is to do what you can to try to create a good practice of getting a good night of uninterrupted sleep and enjoy the benefits that come with it.

If you are sturglging to get uninteruppted sleep you may want to speak with you GP or seek the support of a Psychologist. Psychologists are trained to assist people with sleep issues including sleep intrruptions. Contact us at PHC for more information.