When you sleep, your body and brain go through four sleep stages. Each plays a role in your physical and mental health.
To support overall health and well-being, the American Academy of Sleep Medicine recommends adults get at least seven hours of sleep each night.
During seven hours of sleep, you will cycle through all four stages four or five times. When sleep is cut short or interrupted because of insomnia or other sleep problems, you may not get all the health benefits of a good night’s sleep. As you move through the stages, it gets harder
to be woken up.
The Four Stages of Sleep
Stage N1. This stage is when you first fall asleep and typically lasts one to five minutes. It’s easy to be woken up during N1, so keep your sleep space free of noise, light, or other disruptions.
Stage N2. This stage lasts 10 to 60 minutes, getting longer with each cycle. Your body temperature, breathing, and heart rate begin to drop or slow. The majority of your sleep time is spent in this stage.
Stage N3. Also known as deep sleep or slow-wave sleep, this stage lasts 20 to 40 minutes. Your body fully relaxes as your pulse and breathing rate drop more. To wake up feeling refreshed, you need deep sleep. It may also play a role in learning and your immune system function.
Stage R or REM. REM stands for the rapid eye movement that takes place during this stage. This is when you dream. The percentage of REM sleep increases with each cycle. Sleep experts think that during REM sleep, your brain files away certain memories and information and gets rid of mental clutter.