Whether you feel like you're not getting enough sleep, you've recently realized that magnesium helps you maximize your shut-eye, or you've started to track your sleep data so you can start learning more about your individual sleep needs, understanding your sleep cycles is key to determining your sleep health.
Each night, you move through four to six sleep cycles. Each cycle is made up of four stages, and each stage is imperative to helping you feel rested and supporting your overall well-being. There are many factors that can cause issues with sleep, including anxiety, stressful life events, and health issues. Understanding your sleep cycles—and the amount of time you're spending in each cycle—can help you optimize your sleep routine to help you feel your best.
What is a sleep cycle?
Getting enough sleep isn't the only thing that matters when it comes to feeling refreshed in the morning. As you move through sleep cycles each night, your body moves through four different stages.
As you move through the night, the amount of time you spend in each stage within each sleep cycle changes. In addition to this normal variation, certain factors can affect the amount of time you spend in each sleep stage, including alcohol consumption and age.
Now, we'll take a look at what each of the four stages of sleep entails.
The four stages of sleep
The breakdown of your sleep cycles is known as sleep architecture, and is composed of stages that are split into two categories: NREM (Non-REM) sleep and REM sleep.
Stage 1: N1
Lasting up to 7 minutes, the N1 stage of sleep occurs when you first fall asleep. The body is beginning to ease into full relaxation as movements of both the brain and body begin to slow. You may experience sleep twitches during this stage, and you may hear non-existent loud noises that startle you awake. While it's easy to wake someone up in the first stage of sleep, an undisturbed stage 1 can quickly lead to deeper sleep.
Stage 2: N2
During the second stage of sleep, your body temperature drops, your heart rate slows, and your muscles begin to relax. Eye movement ceases, and breathing begins to slow. This cycle lasts about 15 minutes in the first sleep cycle of the night, and becomes longer as cycles progress. This stage typically repeats between stages 3 and 4.
Stage 3: N3 slow-wave sleep
In this deep sleep phase, many of the body's processes, including pulse and breathing, slow even further. Current research suggests that despite the reduced level of brain activity during stage 3, spending time in this phase can promote memory, creativity, and deep thinking. This stage of sleep is very deep, and people who are awakened during this phase may feel foggy if awakened before moving on to REM sleep. You spend 20 to 40 minutes in this phase earlier in the night. This time slowly diminishes as you move toward the morning.
Stage 4: REM sleep
Your brain is super-active during this phase, as are your eyes and your respiratory system. The rest of the body experiences temporary paralysis. Dreams are most common during this phase, and tend to be more intense than dreams during other phases. REM stages get longer throughout the night. In your first sleep cycle, your REM sleep may only last a few minutes. During your last sleep cycle, your REM sleep can last for an hour or more.
REM sleep is thought to assist in the formation of memories, and can work to help your mind process stressful information. Motor learning is also supported by REM sleep. Failing to get enough REM sleep can cause serious health problems—evidence even suggests that prolonged REM sleep deprivation can cause death.
How long is a typical sleep cycle?
Typically, a sleep cycle lasts about 90 minutes (although this can vary). It's ideal to aim for four to six sleep cycles per night, but even a single sleep cycle can help your body and mind feel refreshed.
Understanding individual variations in sleep cycles
Sleep cycles can vary, and what you see from your sleep data one night may differ from what you see the next night. Factors that you might not notice during your day—such as the amount of time you spend in the sun and the type of light you're around at night—can impact your sleeping cycles.
Other factors, like traumatic brain injuries, depression, age, and certain medications can all impact your sleep cycles. If you're struggling to get restful sleep and you aren't sure why, it's a good idea to talk with your doctor about whether it would make sense to schedule a sleep study.
Tracking, monitoring, and interpreting your sleep cycles
Understanding your current sleep patterns and your sleep needs can help you make the most out of your rest. Tracking your sleep isn't just about seeing the numbers and charts on your tracking device when you wake up—it's also about paying attention to how you feel each day to understand what amount of sleep is the best fit for your needs.
Using an app like Evidation can help you learn more about how your sleep habits intertwine with your overall sense of well-being, allowing you to make the changes necessary to feel your best. Taking your data to an appointment with your health care professional can also help you work together to determine changes you could make to get more restful sleep.
The role of Evidation in sleep cycle monitoring
No matter what type of sleep tracker you use, Evidation is here to help you put your health data to good use. With your permission, we'll use your health data to provide you with personalized insights and information that you can use to support your well-being. Get started by learning more and downloading the app today!
