Sleep is an essential part of life, and it’s something that we all need to function properly. While most of us know that sleep is important, few people understand exactly what goes on while we sleep.
There are different sleep cycles that our bodies go through while we sleep, and understanding these cycles can help us to get better sleep and wake up feeling more rested and refreshed. In this blog post, we’ll take a closer look at the different sleep cycles and what happens during each one.
What Are Sleep Cycles?
Before we dive into the different sleep cycles, it’s important to understand what sleep cycles are. Sleep cycles are the stages of sleep that we go through throughout the night. These cycles are typically about 90 minutes long and involve different stages of sleep.
There are two main types of sleep: REM (rapid eye movement) and non-REM sleep. Non-REM sleep is further divided into three stages: N1, N2, and N3. We’ll take a closer look at each of these stages in the following sections.
Stage 1: N1 Sleep
The first stage of sleep is known as N1 sleep, and it’s the lightest stage of sleep. During this stage, our bodies are just starting to relax and we may feel drowsy, but we’re still relatively alert and can be easily awakened.
During N1 sleep, our bodies start to produce slow brain waves and our muscle tone decreases. Our eyes are closed, but we may experience twitching or jerking movements. This stage of sleep typically lasts for about 10-15 minutes.
Stage 2: N2 Sleep
The second stage of sleep is known as N2 sleep, and it’s a slightly deeper stage of sleep. During this stage, our bodies become even more relaxed and our brain waves slow down even more. Our bodies also start to produce short bursts of rapid brain waves known as sleep spindles.
During N2 sleep, our bodies are more difficult to wake up, but we can still be awakened if necessary. This stage of sleep typically lasts for about 20-25 minutes.
Stage 3: N3 Sleep
The third and final stage of non-REM sleep is known as N3 sleep, and it’s the deepest stage of sleep. During this stage, our bodies are completely relaxed and our brain waves slow down even more. This stage of sleep is also known as slow-wave or delta sleep.
During N3 sleep, our bodies are very difficult to wake up, and we may feel disoriented if we are awakened during this stage. This stage of sleep is also when our bodies repair and regenerate tissues, build bone and muscle, and strengthen the immune system. This stage of sleep typically lasts for about 20-40 minutes.
Stage 4: REM Sleep
After we’ve gone through the three stages of non-REM sleep, we enter the REM stage of sleep. REM stands for rapid eye movement, and it’s during this stage that we experience most of our dreaming.
During REM sleep, our brains are more active and our bodies are completely paralyzed. This is a natural defense mechanism to prevent us from acting out our dreams. Our breathing becomes more shallow and irregular, and our heart rate and blood pressure may increase.
REM sleep is important for learning and memory consolidation, and it’s also when our bodies release growth hormone. This stage of sleep typically lasts for about 10-60 minutes.
How Many Sleep Cycles Do We Go Through in a Night?
On average, we go through about four to six sleep cycles