Sleep isn’t just falling into some unconscious realm and waking up refreshed. Sleep is made up of cycles—all of which are crucial to getting a full night's sleep. You progress through NREM stages one, two and three before finally into REM sleep and back again. Each complete cycle takes from 90 to 110 minutes. Here’s what you experience and some facts about each stage.
Stage 1: Falling asleep
- In Stage 1, you are easily awakened.
- Your eyes are closed but you’re not deeply asleep.
- This is where that “falling” sensation occurs. This may be caused by all your muscles relaxing at one time and it is usually followed by sudden muscle contractions.
Stage 2: Light sleep
- Eye movements and brain waves both become slower.
- You’re starting to physically become more “at rest.”
- Your heart rate slows and your body temperature drops.
- You are still experiencing an occasional burst of rapid brain waves.
Stage 3: Delta wave sleep
- It is very difficult to wake you up and when you are awakened you are likely to feel disoriented.
- Deep, restorative sleep.
- There is no muscle or eye movement.
- Your body is repairing and re-growing tissues, building bone and muscle and strengthening your immune system.
- This is the sleep stage where children are more likely to wet the bed, walk in their sleep or have sleep terrors.
Stage 4: REM sleep
- Your brain waves during this stage increase the levels experienced when you are awake.
- Heart rates increases and blood pressure rises, but you may lose some ability to regulate temperature.
- The first REM period is usually about 10 minutes long, but the REM periods increase in time as you experience more sleep cycles. The last REM cycle may be an hour long.
- Babies spend up to 50% of their sleep in REM sleep; adults only spend about 20% there and about half their time in Stage 2.
- As you age, you have less REM sleep.
Getting a great night's rest relies heavily on the quality of your sleep surface. Not sure if your mattress is providing you with restful, restorative sleep? It might be time for a new mattress!