Aside from gallons of coffee and energy bars, sleep is your primary instrument to restore your energy and let your wandering mind chill a bit. Still, an unoptimized sleeping routine (affecting more than 50% of adults) may fail to deliver you energy, cause stronger fatigue, spoil your mood and work productivity.
Think back on your mornings — sometimes, when you wake up, you may feel even more tired than before falling asleep. Yet, on other days, you jump out of your bed, full of energy and ready to knock the world flat. When thinking about this inconsistency, you may think, "What in the world makes my sleep so different?" and we have an answer to your questions. Read on to learn about the main sleep stages and how they affect the quality of your sleep.
Sleep cycle and its connection to circadian rhythms
At first sight, sleep may appear like a prolonged resting period. Plus, aside from dreaming, you don't have any memories of the process itself. Still, when you're sleeping, your brain and body face repeating sleep cycles that continue for 90 minutes. Each cycle comprises four stages — the duration and quality of sleep during each stage strongly affect your energy and productivity in the morning.
The process of sleeping connects to circadian rhythms or your natural inner clocks that send your body signals for action. For example, these clocks tell your stomach when to produce gastric juice, help your body regulate the temperature, hormonal balance, and, finally, prepare your brain for waking up and falling asleep.
Imagine that your brain has already received the signal to prepare for sleep. Then your body temperature decreases, and your pineal gland starts to synthesize melatonin. But, wait a minute — you completely forgot to send a few emails to your colleagues!
When you open your inbox (hey, blue light from the screen starts to suppress melatonin production), you remember that you need to fix something in your work documents. So your brain can't help but turn on the thinking processes until you're done.
After that, when your head is finally on the pillow, you'll realize that you don't want to sleep anymore. It results in hours of tossing and turning in bed. If you manage to fall asleep, your sleep cycles will mess up, which leads to fatigue and low productivity in the morning.
Sounds creepy, right? Still, by learning more about the sleep stages you'll be able to evaluate your resting quality and optimize it. It's your chance to be one step closer to a perfect sleep routine that will help your body and mind recover more strengths during the night.
So, during the night, you go through sleep cycles that last 1,5 hours and consist of four sleep stages. In general, you can divide these stages into REM and NREM sleep. So, let's take a glimpse at them.
NREM (non-rapid eye movement) sleep stages
Do you recall this feeling when you're balancing on the verge of wakefulness and sleep? That's when NREM or dreamless sleep stages occur. These stages are preparing your brain and body for the REM stage. NREM sleep allows your body and brain to rest and regenerate without any external stimulation or actions required. This is also why it is referred to as “the magic stage” by some researchers.
First sleep stage or N1 (3-5 minutes)
During this stage, you begin to doze off, and if nothing interrupts you, in 3-5 minutes, you'll be able to move to the next sleep stage. Meanwhile, your muscles are still a bit tense, all your inner processes, including brain work, are slowing down. Do you know this odd feeling when you wince in the middle of your sleep? They signal that your body is entering the first sleep stage.
It's essential to avoid all stressors, like external light and noise sources, because, during the N1 stage, your sleep is still too superficial. Plus, you may find it hard to fall asleep again later if you wake up during this stage. That's why we recommend you to fall asleep in complete darkness and silence so that nothing will disrupt you.
Second sleep stage or N2 (10-20 minutes)
At this stage, you can't wake up so quickly, and your muscles begin to relax with short periods of tension. In addition, your heartbeat and temperature continue to decrease, preparing the body for deep sleep. Each new N1 stage during the night can also last longer than the previous one. The second sleep stage also involves the pattern that helps you awake faster if needed.
Moreover, during the N2 sleep stage, your brain activity becomes irregular: slow waves alternate with sudden bursts (sleep spindles). According to scientists, these brain activity bursts are essential to consolidate memories and information that you've gathered during the day.
Third sleep stage or N3 (25-45 minutes)
At this stage, you finally enter deep sleep but still without dreaming. Blood pressure and heartbeat decrease while your brain receives less blood, which allows it to cool down and recover. At this sleep stage, external stressors can hardly wake you, and your muscles are fully relaxed.
Your third sleep stage must be long enough, as, on this stage, your body turns on all recovering processes. Research claims that deep quiet sleep helps you produce growth hormones, which help repair your muscles and tissues.
The third sleep stage also plays an essential role in supporting your immunity and defending your body from infections. So if you don't have enough sleep, your immunity weakens, and you become more vulnerable to dangerous viruses and bacteria.
REM rapid eye movement sleep stage (10-15 minutes)
After going through three NREM sleep stages, the cycle comes to a final stage before repeating itself. It's a REM stage, which allows us to see dreams, process information, and make memories.
During the REM sleep stage, your brain activity rises along with heartbeat and blood pressure. At the same time, your body activates other inner processes like the production of digestive juice. Still, your muscles remain paralyzed, so you can't harm yourself or anyone who is near you when you're dreaming.
Harvard Medical School study claims that the REM sleep stage helps you process complex information and strong emotions by converting them into dreams. Moreover, suppose you want to learn a new language or gain a new skill. In that case, the REM stage will assist you by supporting your procedural memory.
As for the Valley Sleep Center research, the REM sleep stage involves essential neural connections, positively affecting your mood and wellbeing by releasing dopamine and serotonin hormones. In addition, when you go through the REM stage, your brain consumes more oxygen than when you're awake, working hard to create long-term memories. Thus, getting enough REM sleep is vital for your cognitive performance and work productivity.
As you can see, each sleep stage is responsible for particular processes, be it learning, strengthening your immunity, or recovering your body and mind. When you fail to get enough sleep during one of these stages, it may lead to severe diseases and sleep disorders. That's why you should always strive to get enough sleep hours. Still, let's uncover the dangers that come with an insufficient duration of sleep stages.
Why is it dangerous to not get enough NREM or REM sleep?
It's hard to measure the time you spent on each sleep stage during the night so that you won't notice the problem immediately. Unfortunately, if you regularly disrupt one of your sleep stages, it may lead to dangerous long-term consequences.
According to a Harvard Health Publishing study, an insufficient amount of both NREM and REM sleep stages links to premature death. In addition, getting too little deep quiet sleep (N3) increases your risks of getting diabetes, obesity, mood disorders, and heart diseases. Plus, people who don't get enough deep quiet sleep are more prone to getting dementia and Alzheimer's.
At the same time, obtaining not enough REM sleep during the night may lead to depression, anxiety, and mood disorders (for example, bipolar disorder). It happens because of emotional stress accumulation, so your brain can't get rid of anxious thoughts and process emotions. Plus, since the REM sleep stage is responsible for helping you memorize and learn, its low duration can make it harder for you to develop new skills.
So it's clear that both REM and NREM sleep stages are crucial for your mental and physical well being. Still, how can you ensure that you get enough sleep at each stage? Our tips will help you measure your sleep stages, optimize them to boost your productivity, maintain good health, and keep your mind sharp.
Tips on how to optimize your sleep stages:
1. Measure your sleep with sleep trackers
Indeed, you can't control the process of sleeping. Then get yourself a sleep tracker that sends reports with each sleep stage duration, and you'll be able to adjust your sleep patterns.
While there is no single perfect way to determine your sleep patterns, there is one thing that you can measure to give indications of how well you are sleeping - heart rate variability. It reflects the amount of time it takes for your heart rate to return to its normal rhythm after an episode of high heart rate (during light sleep) or low heart rate (during deep sleep). Studies have shown that the lower this number is, the more likely you are suffering from insomnia and other related symptoms such as mood swings.
Sleep trackers also give you a chance to experiment and find the best possible sleep environment. For example, monitor your sleep stages duration after sleeping in a room with a warmer temperature or a different pillow. Then track the results, and you'll find out what's best for your sleep.
2. Make sure your bedroom temperature isn't too hot
Journal of Physiological Anthropology study has shown that heat exposure and excessive humidity in your bedroom lowers your REM and NREM sleep duration. Plus, high temperature during sleep contributes to wakefulness and insomnia.
So the perfect temperature for a bedroom is better colder than warmer with moderate humidity. As for Sleep Foundation, an optimal temperature for calmful sleeping is 65 F or 18,3 C.
3. Exercise regularly to extend your deep sleep stage duration
You should have noticed that you doze off the moment your head touches the pillow after days full of different physical activities. In turn, on the days when you weren't so active, you may still be full of energy during bedtime.
Regular exercise can help you achieve healthy deep sleep. In fact, a study found that people who exercised at least 4 hours each week had over 30% more deep sleep than those who didn’t exercise at all.
Exercise plays a huge role in extending the duration of the deep sleep stage. This is because when we use our muscles during physical activity, it releases endorphins that make us feel happy and relaxed instead of anxious or stressed out like other activities do. As a result, our brain releases chemicals that encourage us to take a nap during the day or fall asleep easier at night time without having insomnia symptoms.
If you want to have a genuinely restorative deep sleep every night, moderate exercising for half an hour may help. Just make sure you don't work out right before bed since it may disrupt your sleep patterns.
4. Practice meditations to get more REM and NREM sleep
Meditation isn't just a perfect way to destress and blow off some steam after a hard-working day. It can also help you optimize your sleep stages. Survey has proven that meditators manage to get more slow-wave or deep quiet sleep and REM sleep.
Put your sleep first at least a few times a week, and instead of watching TV before bed, try performing a short meditation with calmful music. Then you'll see how even such a minor activity alters the whole sleeping routine.
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