Understanding the stages of sleep

Sleep is vital to our well-being and health. Understanding the stages of sleep can help us appreciate its complexity and importance.

A person touching an alarm clock.
Photo: Pexels/Acharaporn Kamornboonyarush.

Sleep is a fundamental aspect of human life, yet its intricate stages often remain a mystery to many. Understanding these stages is crucial, as each plays a vital role in our overall health and well-being.

By learning about these stages, you can find ways to get better rest. Whether you are curious or want to improve your sleep, this information can help you appreciate what your body goes through each night so you can wake up feeling refreshed and ready for the day. The stages of sleep are:

Stage 1, NREM (Non-Rapid Eye Movement) Sleep

  • What happens:
    • This is the transition between wakefulness and sleep.
    • Your muscles begin to relax, and your heartbeat and breathing slow down.
    • You might experience slight twitches and a sensation of falling.
  • Why it's important:
    • It’s a brief stage that helps you move from being awake to being asleep.

Stage 2, NREM Sleep

  • What happens:
    • Your body temperature drops.
    • Heart rate and breathing become more regular.
    • Brain activity slows, but you experience brief bursts of activity known as sleep spindles.
  • Why it's important:
    • This stage prepares your body for deep sleep.
    • It accounts for about 50% of your total sleep time.

Stage 3, NREM Sleep (Deep Sleep)

  • What happens:
    • This is the deepest and most restorative stage of sleep.
    • Your heartbeat and breathing are at their lowest levels.
    • Muscles are completely relaxed, and brain waves slow down significantly.
  • Why it's important:
    • This stage is crucial for physical repair and growth.
    • It boosts your immune system and supports overall bodily functions.
    • Deep sleep is also when the body releases growth hormones and repairs tissues and muscles.

Stage 4, REM (Rapid Eye Movement) Sleep

  • What happens:
    • Brain activity increases, and dreams occur during this stage.
    • Your heart rate and breathing become irregular, and your muscles become temporarily paralyzed to prevent you from acting out your dreams.
  • Why it's important:
    • REM sleep plays a vital role in cognitive functions like memory, learning and creativity.
    • It helps process emotions and experiences from the day.
    • REM sleep cycles become longer as the night progresses, making up about 20-25% of your total sleep.

Throughout the night, you engage in the sleep cycle, meaning you cycle through these stages multiple times.  Each cycle lasts about 80-100 minutes. A typical night’s sleep includes:

  • Four to six sleep cycles.
  • A mix of light, deep and REM sleep.

Why are these sleep stages important?

Each stage of sleep plays a crucial role in upholding physical health, cognitive function, and emotional well-being. Disruptions in these stages can lead to sleep disorders, affecting overall well-being and lowering the quality of life. Understanding these stages helps recognize and address sleep problems, leading to better management and improvement of sleep patterns.

Tips for better sleep and improving sleep hygiene or routines

  • Maintain a routine and consistent sleep schedule. Go to bed and wake up around the same time every day.
  • Create a comfortable sleep environment. Keep the room you sleep in cool, dark and quiet.
  • Limit blue light exposure by reducing screen time before bed.
  • Avoid stimulants. Limit caffeine and alcohol intake, especially in the evening.
  • Relax before bed by establishing a calming bedtime routine, such as reading or meditating.

Understanding the stages of sleep can empower individuals to prioritize and optimize their sleep habits, leading to better overall health and well-being. By recognizing the importance of each stage, we can take steps to ensure a good night's sleep and reap the numerous benefits it offers.

If you want to learn more about sleep hygiene and find ways to improve your sleep, consider enrolling in Michigan State University Extension's SLEEP (Sleep Education for Everyone Program). SLEEP is a six-week program that offers guidelines to help adults improve sleep hygiene practices, which are behaviors that enhance sleep quality. Consult a healthcare professional or sleep specialist for more information and personalized advice.

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