Getting a good night’s sleep is considered one of the best things you can do for your health. It’s recommended that adults get 7-9 hours of sleep. But not all nine hours are created equal. Sleep quality is important. Each stage of sleep through the night is an important part of understanding how you can wake up feeling refreshed.
What is the sleep cycle?
A full sleep cycle is made up of four stages. They are determined by brain wave activity. There is one rapid eye movement sleep (REM sleep) and three non-REM (NREM) sleep cycles.
The first stage is nREM or N1. It lasts about seven minutes. The body isn’t fully relaxed. Brain activity is beginning to slow and has few light changes.
The second stage is nREM or N2, lasting 10-25 minutes. The body drops in temperature, muscles relax further and breathing and pulse slow. The brain slows, but studies show minimal activity prevents the body from being woken up. It can last longer than 25 minutes.
The third stage is also nREM. This is deep sleep. It’s also known as N3, slow-wave, or delta sleep. It lasts up to 40 minutes. This is the hardest stage to wake someone from. The body relaxes a lot more. Breathing and pulse rate decrease. The brain wave activity in this stage is known as delta waves. This is why the stage is known as delta sleep. This stage is vital for body recovery and boosts immune function. Studies show that having uninterrupted and regular N3 sleep boosts creativity, cognitive function, and memory. The body remains in N3 through the first half of the night. The stages get shorter in the sleep cycle as the night continues.
This is REM sleep, and it lasts up to 60 minutes. Brain activity increases, closer to how active it is when you’re awake. The body also experiences temporary paralysis of the muscles. Only the eyes and muscles that control breathing remain active. This is when you experience dreams. It’s also vital for physical health, memory, creativity, and body function.
If you fall asleep at 10 pm, the N1 stage lasts up to 7 minutes. You then experience N2, N3, and N4 stages until around 11.30 pm. After this, you experience longer N2, N3, and N4 stages. If you wake up at 6 am, from around 4 am, you experience the longest N2 stage, a shorter N3 stage, and the longest N4 stage. From around 5.30 am to 6 am, experience N2 sleep until your alarm rings.
How can you ensure you wake up feeling refreshed?
The cycles can be described as light sleep, dream sleep, deep sleep then light sleep. The complete sleep cycle lasts about 90 minutes.
Dr Karan Rajan, a surgeon with the National Health Service in the UK, suggests you identify when you want to wake up. If you want to wake up without feeling tired, ensure that you wake up at the cycle closest to the wake stage, the N2 stage. Count back in 90 minutes block to set your alarm for when you are back in the light sleep stage. You will wake up feeling fresher when you wake up at the end of a 90-minute sleep cycle.
If you need to wake up at 8 am, count back in 90-minute blocks until you reach the time closest to when you want to go to bed. That should be your bedtime. As a result, you want to sleep for around 8 hours and, wake up at 8 am, count backwards until 11 pm. That should be your bedtime if you want to wake up feeling refreshed.
Gloria Mari is a culture writer based in Nairobi, Kenya. She writes on art, film, literature, health, and the environment. She has previously written for Kenya Buzz, People Daily, The Elephant, and Kalahari Review.