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Sleep deprivation can have far-reaching effects on your daily life and your health, but many Americans don’t get as much sleep as they should. What do you need to know about the 5 stages of sleep?
Get some sleep. It’s common advice often heard from doctors, mothers and caring spouses, but what is so important about sleep anyway? For many people, sleep tends to be viewed as an inconvenient necessity more than a vital component of healthy living—that’s especially true of entrepreneurs and working types who thrive on burning the midnight oil.
However, a good night’s sleep is something that has no substitute, and it’s essential to your health, focus and wellness. In fact, if you work on providing yourself with better, more restful sleep, then you might notice that you’re more efficient than you ever were working into the late hours of the night. Sure, an all-nighter might be necessary here and there, but you should make a priority of sleeping enough each night and recognizing the quality of the sleep you’re getting.
Unfortunately, it’s not enough to simply lie down for eight hours and doze off. Your body will cycle through various stages of sleep, and it’s only in the deeper phases of sleep that you’ll experience the restorative benefits of those eight hours. If you’re kept up at night by stress, or if you tend to toss and turn frequently in your sleep and wake up throughout the night, chances are you’re not getting enough high-quality sleep. As a result, you might notice that it’s harder to keep your mood stable, fend off food cravings or stay focused at work.
Your body depends on sleep, so if you’re not getting enough of it, you should take the time to understand why. Then, you will want to take steps to actively improve your sleep cycle for more wakefulness, focus and energy each day. Being able to understand how to improve sleep quality now will help you long term. Don’t fall for the cliche of “I’ll sleep when I’m dead” like Dr. John Shufeldt did for so long, now is the time to sleep better.
Why Do We Need Sleep?
Despite extensive research, it’s still not clear what exactly happens during sleep. However, it is generally recognized that sleep fulfills two essential functions. First, it helps the body repair and restore its vital organ systems. This includes immune cells, which are more active in defending the body during sleep, as well as muscles and elements of the endocrine system—the system responsible for producing and regulating hormones in the body.
Additionally, sleep is vital for brain function and memory. In other words, sleep is the process by which we organize and store information learned in the previous day. So, if you’re short on sleep, you might not only struggle with many physical signs of fatigue, but you might also have a harder time remembering recently learned information.
Some studies have actually indicated that sleeping immediately after learning new information can slow down the rate of memory deterioration that occurs, so you’ll remember the information more accurately. One such study had two groups of students memorize two sets of word pairs—one with matching, semantically related pairs and one with completely unrelated words. One group learned the words at 9 a.m. while the others learned the words at 9 p.m. Both groups were asked to recall the words the following morning. While there was no measurable difference in recalling the related word pairs, the group that was given the word pairs at night were able to recall the unrelated word pairs more quickly and easily than the group given the word pairs in the morning the previous day.
Anecdotally, you may also observe the link between sleep and memory retention. For example, you may notice that your dreams often seem related to conversations and events that occurred the previous day.
Understanding the 5 Stages of Sleep
Sleep is not a static activity. In fact, the body cycles through many different stages of sleep in the night without you realizing it at all. When you first fall asleep, your body will be in a stage of light sleep, where you can be easily awoken.
As you sleep longer, you are likely to drift into deeper stages of sleep, which are the ones that have the most profound impact on your brain and your body. In these deeper sleep stages, it is much more difficult to wake someone up. There are also some distinct differences in brain activity that could be the key to better understanding of why we need to sleep at all.
- Stage 1 – In stage 1 sleep, you are hardly asleep at all—think taking a light nap on the couch. Your muscles are still active and your breathing remains steady and normal. It would not take much to wake you at this stage. Additionally, EEG brain frequency is only slightly slower than it would be during wake time. Stage 1 can last up to 7 minutes from when you first fall asleep.
- Stage 2 – When you reach stage 2 sleep, you are still in a state of light sleep, but brain activity starts to look different. It will become slightly harder to wake you from stage 2 sleep, and an EEG would show sleep spindles, or sudden bursts of oscillatory brain activity. Sleep spindles are thought to indicate when the brain is actively inhibiting normal mental processing, so that you stay in a more tranquil state as you drift into deeper stages of sleep.
- Stage 3 – In stage 3, you enter what’s called slow wave sleep, or SWS. It is also sometimes referred to as delta sleep or deep sleep. In this stage of the sleep cycle, it is incredibly difficult to rouse a sleeper. If you are in a deep sleep, even very loud noises measuring up to 100 decibels may not wake you. However, if you do awaken from a deep sleep, you will experience a period of sleep inertia. This means that following being woken up, you will have a much longer period of grogginess than with other stages of sleep. For up to 30 minutes, you might feel particularly fatigued and exhausted, and you are likely to be unable to perform mental tasks at a normal level of proficiency.
- Stage 4 – Stage 4 sleep is also a deep sleep stage. During this stage, sleep spindles are seen as well as K-complexes. These EEG patterns are exclusive to NREM sleep and tend to occur most at the beginning and end of the deep sleep phases. This is when the body repairs muscles and tissues, stimulates growth and development, boosts immune function and builds up energy for the next day. In general, adults will experience less sleep in stages 3 and 4 as they get older, spending more time in stage 2 and stage 5 REM sleep throughout the night.
- Stage 5 – Stage 5 sleep is where REM sleep occurs, or rapid eye movement sleep. It is characterized by dreaming as well as atonic skeletal muscles and rapid, irregular breathing. People typically enter enter REM sleep about 90 minutes after initially falling asleep. Each REM stage can last about an hour and an average adult has 5 to 6 REM cycles every night. This is when your brain consolidates and processes information from the day before – storing that information in long-term memory. All mammals experience REM sleep, which is physiologically much different from all other sleep cycles.
Knowing the 5 stages of sleep will hopefully help you get a small glimpse into why you may not feel rested. Not being able to completely go through all the stages at night can really hinder how you feel the next day.
Why is REM Sleep Important?
The question “Why is REM sleep important” is very common. REM sleep is distinct from the light and deep sleep stages of non-REM, or NREM, sleep. During REM sleep, the brain is much more active than in other sleep stages, more closely resembling brain activity during awake time. Because REM sleep is the part of the sleep cycle most closely associated with dreaming, it is thought that this type of sleep is necessary for processing and storing information in the brain.
REM sleep is so named because all voluntary muscles in the body besides the eye muscles are atonic in this stage of sleep. In other words, the muscles cannot move as normal, but twitching and other movements may still be seen in the eyes. It is likely that this trait developed to protect the body from injury during sleep, since dreams may cause the body to act out physically.
How We Know What Happens During Sleep
Sleep science is a constantly evolving field and there is still a lot that is unknown about what happens during the 5 stages of sleep. In particular, it is uncertain what exactly dreams are and why people have them. However, there is a great deal of information available about why we sleep and the effects sleep has on the body and mind. These effects are perhaps best observed in the absence of sleep. In studies where individuals have voluntarily been deprived of sleep, a measurable cognitive decline has been observed for every hour of sleep lost. So, not only can sleep deprivation have a profound effect on your brain’s processing power, but it can begin to have an effect with just a moderate amount of sleep loss.
How To Improve Sleep Quality
Unfortunately, despite the importance of a good night’s sleep, many Americans simply do not get enough nightly rest. About 35.3% of American adults report getting less than seven hours of sleep in a given 24-hour period. If you aren’t getting sufficient sleep, or your sleep trends toward light sleep without much restorative slow wave sleep, there are steps you can take to sleep better. How to improve sleep quality:
- Say No to Blue Light Exposure – An unintended consequence of our increasingly digital lifestyles is time spent looking at screens. When you spend your evening scrolling through social media or checking your email, you may be negatively impacting the quality of your sleep. For that reason, banning electronic screens from the bedroom is an important part of improving your sleep.
- You might also disable your mobile service and Wi-Fi to limit nighttime disruptions from your phone.
- Bedtime Environment– Your body prefers specific conditions for sleep and without them you may not fall into a healthy sleep cycle. Cooler temperatures, minimal external noise and darkness can help you sleep better. You can even go as far as looking at your mattress and pillows to see if they are hindering how you sleep.
- Drink Less Before Bed – Getting up at night to go to the restroom multiple times can really disrupt your sleep. Remember to use the restroom right before you go to bed so you do not have as high of a chance of waking up at night.
- Limit Caffeine – Caffeine later in the day will stimulate your body and will not let your body naturally relax during the night. This is because caffeine can stay in your system for six to eight hours. In fact, one study has shown that people’s sleep quality is worse if they consumed caffeine up to six hours before they went to sleep.
- Cut Alcohol – Drinking at night typically has a negative effect on sleep and is even known to increase peoples’ risk for sleep apnea. In addition, alcohol can reduce your nighttime melatonin that helps tell your body to sleep.
- Better Timing – If you don’t have any trouble falling asleep but still tend to wake up tired and groggy, you may be waking up in the wrong part of your sleep cycle. Fortunately, there is a solution with sleep cycle monitoring to sensing the right moment for your alarm clock to go off. This will ensure that you awaken in a lighter sleep stage, so you won’t suffer from the typical morning grogginess. Try to go to sleep and wake up consistently.
- Expose Yourself to More Bright Lights in the Daytime – Your inner clock, circadian rhythm, affects how your brain tells your body when you should go to sleep. When you are exposed to bright lights or natural sunlight during the day, your circadian rhythm has a better chance to tell your brain to sleep at night.
- Relaxation Techniques – Relaxing music, books, hot baths, meditation, massages, breathing techniques and yoga can help clear your mind and help you fall asleep. Exercise Regularly – This is not only good for sleep, but your overall health. However, exercising late at night can have a negative effect since exercise naturally increases alertness and hormones.
- Address Snoring – Snoring can keep people up at night and disrupt the quality of your sleep. Make sure you do not have an underlying health issue that can be a sign of snoring (sleep apnea).
With a busy schedule, getting enough sleep can be a challenge. However, it’s one worth pursuing for your personal health and wellness.
Now you know the answer to “why do we need sleep” so that you are able to start making positive sleep habits today. Knowing how to improve sleep quality will ultimately help you become more productive during the day and feel more refreshed in the morning.
Kaleigh Shufeldt is a writer, editor and content manager with a love of sustainability and healthy living. She spends her free time with her husband and dog, Duke, running, reading and cooking.