STAGES OF SLEEP contains multiple sleep cycles. Each Sleep Cycle lasts for approximately 90 minutes. But it may exceeds some times.
Our brain goes through four different STAGES OF SLEEP during your Sleep, each with its own set of activity patterns and each essential to finding a proper night’s sleep requirements. Sleep 7 hours is considered enough to complete Sleep Cycles and the proper amount a sleep.
There’s a lot going on in the body and brain when we turn out the lights and go to Sleep, from physical restoration in our body to memory consolidation to dreaming mode.
As a result, sleep quality is just as important as sleep quantity of Sleep in our life. Our ability to progress through the various stages of Sleep (and spend enough time in the deepest ones) defines whether we’re getting good Sleep at night or not.
“Think of sleep as similar to nutrition,” says John Cline, PhD, an assistant professor of clinical psychology at Yale School of Medicine and fellow of the American Academy of Sleep Medicine. “We want to get a balanced set of sleep stages (just like you want to include a balance of different micro-and micro-nutrients in a healthy diet to stay healthy entire life), as each seems to serve an important function. Furthermore, He adds that cycling through all of the Sleep stages often results in optimal physical, emotional, and cognitive health.
Here’s a deeper examination of the different stages of Sleep that make up a sleep cycle and why each stage is vital for our health and feeling rested when we wake up in the morning.
What Are the 4 Stages of Sleep?
In a nutshell, numerous times during the night, our brains go through four stages of sleep, according to Michelle Drerup, PsyD, a psychologist and director of the Cleveland Clinic’s Behavioral Sleep Medicine Program.
When you’re passed out in bed, your loved ones may describe you as a lump on a log, but a lot is happening inside your eye mask.
There are four distinct sleep stages: three are non-REM (NREM) sleep periods, followed by REM sleep, the fourth and the last stage.
Dr Drerup adds an important disclaimer saying that researchers still don’t know much about what happens in our brains while we sleep.
Much of this discipline’s research is focused on researching sleep patterns and brain waves in patients in a sleep lab to speculate what might be going on when we’re sleeping.
Here’s what we know about the four stages of Sleep so far:
Stages of Sleep: Stage 1 Non-REM (Rapid Eye Movement) Sleep
As we transition from wakefulness to a light slumber, we enter the initial sleep cycle phase: Stage 1. This is the time when you’re just about to fall asleep. Your heart rate, eye movements, and breathing slow down, your muscles relax, and your brain activity decreases; overall, your productivity level starts decreasing. “At this point of the stage, we’re just starting to fall asleep.”
“Sometimes people don’t even feel like they were asleep when they wake up,” Drerup explains.
Though it’s accessible to awake when they’re in stage 1 of the sleep cycle, if they’re not interrupted, they’ll swiftly proceed into stage 2 and get a little difficult to awake.
Stage 1 sleep lasts around 5 to 10 minutes in a typical sleep cycle, especially early at night. And also very age-wise.
Stages of Sleep: Stage 2 Non-REM Sleep
As you drift deeper into the next level of Sleep, during stage 2 non-REM sleep, your heart rate and breathing get slow even more.
The 2nd stage of Sleep is all about getting ready for the upcoming deep sleep and REM sleep stages.
According to Eric Landsness, MD, PhD, an assistant professor of neurology and sleep medicine at Washington University School of Medicine in St. Louis, your body temperature decreases, your muscles completely relax, and your brain waves slow to small bursts of electrical activity. You get difficult to awake as you stay more extended time in this stage.
Electroencephalograms, which measure brain activity while patients sleep, demonstrate how engaging brain wave activity looks during this time, according to Dr Landsness.
NREM sleep is indicated by the firing of sleep spindles (brain wave patterns).
This Sleep spindle activity suggests that memory processing of the day’s events occurs in the brain when the sensory nerve system (sight, hearing, taste, smell, and touch) shuts down for the day.
“there’s a very pleasant feel about it.” “These are neurons delivering messages from your short-term memory to your long-term memory,” Landsness adds, describing them as “tiny spindles on a sewing machine.” He explains that the messaging process is supposed to be how your brain converts short-term memories to long-term memories during Sleep.
According to Drerup, we spend the most time in stage 2 sleep, which accounts for around half of the night and 20 to 60 minutes per cycle.
Read Also: DO YOU KNOW ABOUT SLEEP AND SLEEP CYCLE?
Stages of Sleep: Stage 3 Non-REM Sleep
The deep sleep that our bodies rely on to feel rejuvenated in the morning is the ultimate stage of non-REM Sleep and is called 3rd stage of Non-REM Sleep.
According to Dr Cline, you’re the most disconnected from your waking reality at this stage of Sleep.
In this stage, your heartbeat and breathing slow the most when your body and muscles rest completely, and it’s the most difficult to be awakened during this phase.
During this crucial stage, it’s all about restful Sleep, physical recovery, and fortifying the immune system.
According to Cline, deep Sleep also refreshes the brain, allowing it to encode new memories the next day. And if we continuously get a night of proper sleep in all 4 stages, we will be happier and live longer.
Delta waves, or slow-wave Sleep, characterise brain activity during this period. Because it is more difficult to wake you up in this stage of deep sleep, you may feel groggier than you would if you were awakened during the other sleep stages, according to Drerup.
While memory consolidation occurs during most stages of sleep, research suggests that your brain consolidates memories such as broad knowledge, such as facts or statistics, during this period.
According to Hassam Al-Sharif, MD, a pulmonologist and sleep medicine specialist at the Mayo Clinic in Eau Claire, Wisconsin, “slow-wave sleep is critical for consolidating long-term memories – facts, events, geography, and spatial sense.”
Each sleep cycle, we spend roughly 20 to 40 minutes in stage 3 deep sleep, which prepares us for the Next and final stage of Sleep, the 4th stage.
Stages of Sleep: Stage 4 REM Sleep
Rapid eye movement (REM) sleep is defined by its name as the Final stage of Sleep. On brain scans, your brain activity is so high in this fourth sleep stage that it appears to be awake.
Your heart rate, blood pressure, and breathing all begin to increase again. Your muscles and body are immobile while your eyes dart back and forth, according to Drerup. Body functions get intensive at this stage. Memory consolidation occurs during REM sleep as well.
While the brain is supposed to be processing new facts, locations, or formulas (for example, from a textbook) during deep Sleep of this stage, the brain is thought to be processing abstract thinking and emotional content during REM sleep.
According to Landsness, the brain will hunt for emotional significance as it recalls the events of the last day.
Researchers believe that dreaming happens at all stages of Sleep but that our most vivid, storylike dreams happen during REM sleep as a result of emotional processing.
And because we frequently wake up in the morning during this period of Sleep, we often tend to remember these dreams.
REM sleep is also considered as in charge of processing new motor abilities obtained during the day, storing them in memory and determining which ones to discard and which ones to store. “It appears that REM sleep is a tool for our brains to integrate memories, absorb new knowledge, and deal with events that occurred during the day,” Dr Al-Sharif explains.
REM sleep may last only a few minutes at the start of the night, but it can continue up to half an hour from the second half of the evening until dawn (more on this).
REM sleep accounts for roughly 25% of total sleep time in adults.
What stage of Sleep do you dream in?
When you enter REM sleep, your brain activity spikes again, indicating that your Sleep isn’t as deep. The levels of activity are similar to when you’re awake. That is why REM sleep is so important. After falling asleep, REM sleep occurs approximately an hour to an hour and a half later. When you’re sleeping in REM, you’re more likely to experience vivid dreams. As we fall, sleep our brains start dreaming. But REM is considered a substantial dream stage of Sleep. Because at this stage of sleep, dreaming is remembered.