Sleep Stages: Average Time Spent in Each Sleep Stage

Every night, your body moves through four distinct stages of sleep, each serving a specific purpose in your physical and mental recovery. Understanding how much time you spend in light, deep, and REM sleep helps you interpret your sleep data and make informed decisions about your habits. This article breaks down the stages of sleep and the average time you should spend in each.

What is the sleep cycle?

A sleep cycle is a progression through the different stages of sleep, typically lasting about 90 minutes. Your body repeats this process four to five times per night. The composition of each cycle changes, with more deep sleep occurring earlier and longer REM stages happening closer to the morning.

The 4 stages of sleep

Each sleep stage serves a unique restorative function. Understanding their roles helps clarify why the time spent in each matters.

• Light Sleep: The entry point into sleep, where your body begins to relax.
• Deep Sleep: The physically restorative stage for muscle repair and growth.
• REM Sleep: The mentally restorative stage for memory consolidation and learning.
• Awake: Brief periods of wakefulness that are a normal part of sleep architecture.

Light sleep

Light sleep is the transition period where you can be easily awakened. Your body is more responsive to your environment during this stage.

Deep sleep (SWS)

Deep sleep is the "physically restorative" stage where 95% of human growth hormone is produced. During this time, your muscles and tissues repair themselves. It is often difficult to wake from deep sleep, and doing so can cause grogginess.

REM sleep

REM sleep is the "mentally restorative" stage when the brain converts short-term memories into long-term ones. Your brain is highly active, and your heart rate and respiratory rate increase. This is also when your most vivid dreams occur.

Awake

It is normal to be awake for several brief periods throughout the night. These arousals, or disturbances, are usually brief and you are not conscious of them. Read more about the differences between deep sleep and REM.

How much time should you spend in each sleep stage?

Below is a graphic depicting the average amount of time WHOOP members spend in each of the 4 stages of sleep on a nightly basis, as well as the percentage of total time each stage represents.

The ideal amount of time in each sleep stage varies from person to person and depends on factors like daily activity and recovery needs. However, there are general benchmarks for healthy adults. WHOOP members, who are typically focused on improving their performance, provide a useful data set for these averages.

• Light sleep: Approximately 50%
• REM sleep: 20-25%
• Deep sleep (SWS): 15-25%
• Awake: Approximately 5%

How to improve your sleep stages

While you can't directly control your sleep stages, you can adopt habits that promote better sleep quality and help you get more restorative deep and REM sleep.

• Maintain consistency: Go to bed and wake up around the same time each day, even on weekends.
• Optimize your environment: Keep your bedroom dark, quiet, and cool.
• Avoid disruptors: Limit caffeine and alcohol, especially in the hours before bed.
• Establish a routine: A consistent pre-bed routine signals to your body that it's time to wind down.

Understand your sleep to unlock your potential

Understanding your sleep is about quality, not just total hours. Knowing how much time you spend in each stage gives you the insight to make better decisions about your daily habits and routines. This helps you build a foundation for better health and performance.

WHOOP measures your sleep in detail and provides personalized recommendations with the Sleep Planner, which calculates your nightly sleep need based on your activity and sleep debt.

Frequently asked questions about sleep stages

What does a good sleep cycle look like?

A good sleep cycle shows a clear progression through light, deep, and REM sleep, with deep sleep dominating early in the night and REM sleep increasing later.

How can you tell if someone is in deep sleep?

A person in deep sleep is very difficult to wake, with slow, regular breathing and a still body. If awakened, they will likely feel groggy and disoriented.

Why do sleep stage percentages change nightly?

Your sleep stage percentages vary nightly because your body adjusts its sleep architecture to meet recovery demands from factors like physical strain, mental stress, illness, or diet.