Sleep cycles

All About Sleep Cycles and Their Length

Sleep is one of the cornerstones for good health. A bad night’s sleep can negatively impact a person’s day, and a good night’s sleep can help them feel like they can tackle the world.

But have you ever wondered about the different cycles of sleep and how long they last? If so, read on – we have all the information you’ve been seeking.

How Long Do Sleep Cycles Last?

Sleep cycles are in the neighborhood of 90 minutes, although that amount can vary. Sleep cycles are a mixture of REM, also known as rapid eye movement, and NREM, which is non-rapid eye movement sleep.

The earliest cycle of the night typically carries on between 70 to 100 minutes. But the ones you experience later in the night are longer, between 90 and 120 minutes.

The Stages of NREM Sleep

NREM sleep is the type of sleep that will start off a sleep cycle. There are three stages involved – N1, N2, and N3.

The first stage, N1, is when you’re lightly nodding off. It’s a transition to deeper sleep and usually only lasts for about five minutes.

When you get to N2, your body starts to relax – you’ll have a slower heart rate and your body temperature lowers. This stage takes from 10 to 25 minutes.

The N3 stage, also called slow-wave sleep, typically takes 20 to 40 minutes. If you’ve tried to awaken someone from this stage of sleep, you’ll have noticed it’s harder to do than when they are in the earlier stages.

REM Sleep

REM sleep is the sleep best known because it is well-known as the stage of sleep in which people most often dream, although they can also dream in NREM stages. People in this sleep cycle will have rapidly-darting eyes.

REM sleep happens after you’ve been asleep for 70 to 90 minutes approximately. Your brain is highly active during this phase of sleep. Your breathing isn’t deep, and your blood pressure and heart rate increase.

This type of sleep cycle comes and goes throughout the night. The initial REM stage might be quite short – anywhere from one to five minutes – but they will lengthen later in the night.

More About Sleep Patterns

Why the body goes back and forth between sleep cycles and patterns isn’t understood, but researchers believe the reason is that it’s the best combination for mental and physical optimization.

Not everyone’s sleep patterns are the same though – they can be influenced by age, stress, surrounding environmental factors, an internal clock, and exercise. How much sleep you get and the overall quality of it can impact sleep cycles and their length. But overall, on average, an adult generally is in REM stages about one quarter of the night, while half of the time they’ll be in N2 sleep cycles. The remaining amount will be split between the other stages.

While not everyone requires the same amount of sleep to function at their best, many adults need a minimum of 7.5 to 8 hours. But others may need more than that to feel like they’ve had a good night’s rest.