The 5 Stages of Sleep and Why it is Important

Whether we would like to admit it or not, sleep is a very important bodily process that should not, and cannot be overlooked – lest we run the risk of causing severe harm to our bodies. In fact, one of the most prevalent health problems faced by Americans is, interestingly enough, insomnia. It is estimated that as much as even a third or more of the American population experiences moderate to severe sleep related issues.

These sleep related issues can range from bouts of sleeplessness a couple days a week, to more serious instances of individuals who suffer through endless nights of tossing and turning without any relief in sight. Even if you are lucky enough to not be hounded by such detrimental problems, sleep is still an important part of our daily lives that cannot be overlooked, our health and very lives depend on it. For this reason, we have compiled a breakdown of the five (5) stages of sleep, as well as evident reasons why sleep is important to humans.

Sleep Comes in Five (5) Stages

In total there are five perceptible stages of sleep that we as humans undergo on a normal basis. These stages,often referred to as being “wave-like” typically manifest recurrently throughout periods of healthy sleep.sleep_stages_waves

The first stage of sleep or ‘stage one’, is more technically referred to as light sleep. This is where our bodies initially start to become relaxed and our breathing begins to slow down and become steady. For many individuals (especially those with sleep related issues), inadvertently straying in and out of this initial stage is not uncommon.

As we begin to drift deeper into sleep and enter stage two, our eye movements slow down and eventually stop. This is also accompanied by an overall slowing of our brain waves and nerve impulses. As we enter stage three of sleep or “deep sleep” we begin to experience delta brain waves. These delta brain waves increase in regularity as we progress through stage four of sleep.

While these aforementioned deep sleep stages are actually where vital physiological development, bodily processes and functional repairs mainly occur. In these deep sleep stages there is little to no body movement or eye movement and congruently it is difficult and disorienting to actually awaken an individual when they enter this state. The final and fourth stage of sleep is somewhat different in that it is more focused on the mind rather than the body; REM sleep leads into individuals returning to stage one and starting the cycle once more.

REM sleep is noted specifically for the rapid eye movements that occur throughout it –this is where it gets its name. Certain dynamics such as blood pressure and heart rate noticeably increase during REM sleep; however, unbalanced and shallow breathing is also experienced as well. It should also be noted that dreams occur during REM sleep as well. Dreaming is not as trivial as most of us believe, studies have shown that dreaming and subsequently REM sleep are directly linked to proper mental health. A lack of both has been directly linked to mental issues such as: anxiety, depression and bipolar disorder. Approximately 90% of individuals that experience moderate to severe depression have been shown to have underlying sleep difficulties as well.

What all of this means is that since we only undergo REM sleep as a sleep cycle nears its end we might successively miss out on the benefits that it bestows if we only get a couple hours of rest at a time.

How Does A Lack of Sleep Affect Us?

Over the years numerous studies have revealed that insomnia alone can be responsible for a vast number of mental and physical health related issues. However, even if you are lucky enough to not be hounded by insomnia; here are a few adverse effects that can arise from even a moderate lack of sleep.

You Are More Accident Prone

Recent studies have shown that individuals who have issues sleeping are more prone to injuries and accidents as they go about their daily lives. Directly linked to this is an increased chance of traffic/vehicular related accidents as well. This means that if you neglect to get a good night’s rest and choose to drive or operate heavy machinery the next day you are not only putting your own life at risk, you are putting the lives of other individuals at risk as well.

This is not simply speculation, just recently the National Highway Traffic Safety Administration approximated that every year over 90,000 vehicular accidents are caused by simple fatigue and lack of sleep. Not only is this true they also reported that on average,there are over 1,500 road death annually that are related to fatigue as well. Just as bad and avoidable as being intoxicated behind the wheel.

Your Mental Processes, Memory and Mind Are Affected

By getting little to no sleep for just one night you are severely impacting your ability to: properly concentrate; maintain your attention span; remain alert; and reliably solve problems as they arise. Furthermore, studies have revealed that mental development, reasoning and intelligence levels can be affected by as much as a comparative 40% by just missing one night’s sleep the previous day – this is especially true for younger people.

Sleep also has the added benefit of facilitating the organizing of our daily experiences, memories and things  we have learnt. This is done in an effort to make recollection of any relevant information much easier. For this reason, adequate sleep is an absolute necessity, especially for students who have to carry out a great deal of studying.

Less Sleep May Lead To Weight Gain

If on average an individual chooses to sleep for less than five to six hours, it has been shown that there is a corresponding and very noticeable increase in appetite and feelings of hunger. These hunger urges are, above all, for foods that are rich in carbs and consequently stimulate the secretion of insulin and body fat storage.

A scholarly study conducted in 2014 was able to show that individuals who had under six hours of sleep were actually at over 25% higher risk of obesity compared to individual who had anywhere between just seven to nine hours of uninterrupted sleep. Strangely enough, this same study showed that once the nine hour threshold was passed the related benefits of sleep were actually negligible.

Higher Risk of Diabetes and Heart Disease

In an academic study that was issued in the lauded European Heart Journal, it was stated that individuals who have trouble sleeping and fail to wake up rested are thrice as likely to develop cardiovascular problems over a 5 – 10 year stretch. In fact, issues such as heart attack and stroke are more prevalent insleep_health individuals suffering from insomnia. Diabetes is another health problem that has not only been scientifically linked to insomnia, it has also been linked to simple lack of sleep as well. The dynamic that is now being researched is if these sleep issues are a factor that causes diabetic conditions or if problems sleeping are caused by prediabetic disorders.

Sleep With Regard to Depression

As briefly stated before, depression and insomnia have been found to be directly linked after many extensive studies over the years. Research published in The Journal of Neuroscience showed that various telltale symptoms of depression were approximately five times more probable to occur in individuals who recurrently exhibited an incapability to sleep. While there is some dispute over what actually occurs first – the inability to sleep or the depression – adequate sleep has been cited hundreds of times as one of the simplest and most effective methods of treating depression and its symptoms.

Insomnia Makes You… Older?

While this statement might seem more than a little farfetched, it should not be taken quite as literal as it sounds. What this actually means is that by experiencing insomnia, moderate sleeplessness or fatigue over a long period of time; you are susceptible to negative physical aspects. The stress hormone, better known as Cortisol, is produced and used by the body whenever we are tired. When excessive levels of Cortisol are produced it eventually leads to wrinkles and fine lines because of broken down collagen. In addition to this, it is primarily during deep sleep stages that our bodies grow and perform vital repairs with the aid of human growth hormone.

How is Adequate Sleep Beneficial?

It has been proven that an individual that is adequately rested will, on average, always produce significantly less adrenaline and cortisol – two of the hormones that are largely responsible for stress. Also, if your body does unavoidably produce these hormones during the day, getting adequate sleep will gradually reduce their levels.

Once you awaken feeling sufficiently rested and revitalized you will be far more alert, have larger reserves of energy and think and focus more competently.

Not only is sleep useful for facilitating recovery from sicknesses and ailments insomnia has, in opposition, been observed to make afflicted individuals susceptible to health issues by suppressing their immune systems.

As each day goes by our bodies endure unavoidable wear and tear as we interact with our environment. It is during sleep that our bodies perform repairs and create new cells; this means that the longer you forgo proper sleep the less efficiently your body will perform on both a physical and mental level.

When we sleep our bodies try their best to regulate the various hormones in our bodies. This in turn facilitates digestion and weight loss by giving us greater control over our appetites, among other things. The balancing of these hormones also facilitates happier moods throughout the subsequent day, leading you further and further away from the clutches of depression.


So, just how much sleep should you be getting on a daily basis? Numerous experts agree that in order to have the best chance of avoiding all of the aforementioned negative effects and experience the outlined benefits; the average adult should aim to get at the very least seven hours and at most nine hours of sleep.

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