Stages of the Sleep Cycle Explained

We all know how important it is to get enough hours of sleep, but did you know that the quality of your sleep matters just as much? To feel truly rested, you need to go through the four stages of the sleep cycle multiple times without any interruptions. That's where TEMPUR® comes in - we're here to break down the phases of a sleep cycle and give you some tips on how to improve your sleep quality.

What are the Stages of the Sleep cycle?

Sleep is divided into four stages. One of these stages is called rapid eye movement (REM) sleep, while the other three are known as non-REM (NREM) sleep. Experts can identify each stage by analysing brain activity during sleep, which shows unique patterns for each stage. So, by studying your brain activity while you snooze, we can figure out what stage of sleep you're in.

Lightest Sleep

This initial stage of the sleep cycle serves as a bridge between being awake and falling asleep. If you were to wake someone up during this stage, they might say that they weren't sleeping at all.

In this first stage of sleep:

• Your brain activity starts to decrease
• Your heart rate, eye movements, and breathing follow suit and slow down
• Your body begins to relax and you might experience occasional muscle twitches

During this short nap, your brain enters a stage of sleep where it produces theta waves. Theta waves are slow brainwaves that occur in the brain's frontal lobe. Despite being in a state of sleep, your brain remains fairly active during this phase. Many people find that taking a power nap can help them feel more alert and focused throughout the day. It's important to note that longer naps (over 30 minutes) can lead to grogginess and interfere with nighttime sleep.

Light Sleep

People typically spend around half of their overall sleep duration in NREM sleep, which lasts approximately 20 minutes per cycle.

In this second stage of sleep:

• Your awareness of your environment decreases
• Your body temperature starts to lower
• Your eye movements come to a halt
• Your breathing and heart rate become more consistent

During this stage, the brain starts to generate quick, rhythmic brain wave activity known as sleep spindles. Sleep spindles are believed to play a role in memory consolidation, which is the process where your brain collects, processes, and sorts out new memories from the previous day. In other words, when you're in light sleep, your brain is working to help you remember and process the things you experienced during the day. This is why getting enough quality sleep is so important for overall cognitive function and memory retention.

Deep Sleep

During NREM deep sleep, also known as delta sleep, deep and slow brain waves called delta waves start to appear. This stage is characterised by a deep sleep so intense that it might be challenging to wake the person up, even with loud noises or other disruptions.

 In this stage:

• Your muscles are fully relaxed
• Your blood pressure decreases
• Your breathing slows down
• You enter your deepest phase of sleep

This deep sleep stage is when your body begins its physical restoration. Ensuring you get enough of this NREM deep sleep is key to waking up feeling rejuvenated the next day. In the initial sleep cycles, deep sleep stages typically last between 20 to 40 minutes. However, as your sleep progresses, these stages shorten, and more time is allocated to REM sleep.

 REM

Rapid Eye Movement (REM) sleep is a stage of sleep where your brain becomes very active, almost as if you were awake. During this stage, your body becomes temporarily paralysed, except for your eyes and the muscles that help you breathe. This is why it's called REM sleep.

You usually don't enter the REM sleep stage until about 90 minutes into your sleep cycle. As the night goes on, the time you spend in REM sleep increases, especially during the second half of the night. While the first REM stage may only last a few minutes, later stages can last up to an hour. Overall, REM sleep makes up about 25% of an adult's sleep.

Understanding the meaning of REM sleep and how it fits into the 90-minute sleep cycle can help you plan your sleep schedule, so you get enough restorative sleep.

How long is the sleep cycle?

The first cycle is usually the shortest, lasting around 70 to 100 minutes, while the following cycles tend to last between 90 and 120 minutes. Also, the amount of time spent in each stage of sleep shifts as the night goes on. It's important to note that everyone's sleep cycle is unique and can vary from night to night depending on factors like age, sleep habits, and even alcohol consumption. So, let's explore how you can optimise your sleep cycle for a better night's rest!

 How can you improve your sleep cycle?

 While you can't completely control your sleep cycle, there are things you can do to improve your chances of getting good quality sleep. One important step is to focus on improving your sleep hygiene, which includes your sleep environment and habits.

To improve your sleep hygiene, try to establish a regular sleep routine, get natural daylight exposure during the day, avoid alcohol before bed, and minimise noise and light disturbances in your bedroom. Your mattress, pillows, and sheets can also affect how comfortable your sleep environment is.

By taking these steps, you can help yourself get better quality sleep and align your body's natural sleep rhythm, known as the circadian rhythm. This can lead to improved overall health and wellbeing.

Do you have any other tips for improving your sleep cycle?