Sleep is not one continuous state. Throughout the night, your body moves through different stages that support rest, recovery, memory, and other important functions.
A typical sleep cycle consists of two main types of sleep: non-rapid eye movement (NREM) sleep and rapid eye movement (REM) sleep. These stages repeat several times throughout the night, with each cycle generally lasting around 90 minutes.
NREM Sleep
NREM sleep is divided into three stages, beginning with light sleep and progressing into deeper, more restorative sleep.
Stage 1: Light Sleep
Stage 1 is the transition between being awake and asleep. As you begin to drift off, your eye movements slow and your muscles start to relax.
You are still relatively easy to wake during this stage. This period usually lasts only a few minutes before your body moves into a deeper level of sleep.
Stage 2: Deeper Light Sleep
During Stage 2, your body becomes more relaxed and less aware of its surroundings. Your heart rate slows, your body temperature begins to decrease, and your brain activity changes as you prepare for deeper sleep.
Stage 2 makes up a significant portion of the sleep you get each night and helps your body continue the transition toward restorative sleep.
Stage 3: Deep Sleep
Stage 3 is considered deep sleep. During this stage, your breathing and heart rate slow, and your body focuses on important restorative processes.
Deep sleep is often considered one of the most physically restorative parts of the night. Because it can be more difficult to wake someone during this stage, interruptions to your sleep environment may affect how rested you feel the next day.
Creating a comfortable sleep environment can help support uninterrupted rest. A cooling mattress may be especially helpful for people who tend to sleep warm and want a more comfortable surface throughout the night.
REM Sleep (Stage 4)
REM, or rapid eye movement sleep, is the stage most commonly associated with vivid dreaming.
During REM sleep, brain activity increases, your eyes move rapidly beneath your eyelids, and your heart rate and breathing patterns may become less regular. Your muscles also become temporarily relaxed, which helps prevent you from physically acting out your dreams.
REM sleep first appears after you have progressed through the earlier stages of sleep. As the night continues, the amount of time spent in REM sleep generally increases during later sleep cycles.
Your Sleep Cycles Repeat Throughout the Night
Your body does not move through each sleep stage just once. Instead, you cycle through NREM and REM sleep multiple times throughout the night.
Each stage plays a different role, which is why getting enough uninterrupted sleep is important. Waking frequently or cutting your sleep short may interrupt these natural cycles and affect how rested you feel.
Your sleep environment can also make a difference. Factors such as temperature, comfort, noise, and mattress support may all influence your ability to stay asleep comfortably. If your current bed is no longer meeting your comfort or support needs, exploring different mattress options may help you find a sleep surface that better fits your preferences.
Support Every Stage of Your Sleep
While you cannot control exactly how much time you spend in each stage of sleep, you can support healthier sleep habits by maintaining a consistent schedule and creating a comfortable bedroom environment.
Getting enough sleep gives your body the opportunity to move naturally through each stage, from light sleep to deep sleep and REM. A comfortable mattress and a cool, relaxing environment can help you create the right conditions for a more restful night.
