How Long is One Sleep Cycle and How Much Sleep You Need

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A good night’s sleep is essential for functioning well the next day. Proper sleep helps our bodies and brains recover from everything that they are doing during the day. Unfortunately, many of us don’t sleep enough, or very well, at night and it takes a toll on us during our waking hours.

According to HealthySleep, “the brain goes through characteristic patterns of activity throughout each period of sleep … Understanding these patterns, and the factors that affect them, may help in making choices that will lead to better quality sleep.”

Understanding how your sleep cycle works can help you start to make it your friend. A lot of the things that we do today, like looking at bright screens and going out for a late-night drink or cup of coffee, disrupt our sleep cycle. Adjusting those things can get our sleep cycle back to normal again and help us sleep much better.

Non-REM Sleep

Per WebMD, when we are in non-REM sleep our eyes are closed but it would be easy to wake us up. This is the stage where we are going into light sleep and our muscles are relaxing. Our heart rate slows down, eye movements slow down and body temperature drops before we go into deep sleep – the last stage before REM sleep.

Deep sleep is longer during the first half of the night while REM sleep cycles are shorter. This stage of sleep is the one where brain activity slows. Quality deep sleep helps us feel more refreshed in the morning. As we get older, we need less deep sleep.

How Long is One REM Cycle?

Rapid Eye Movement Sleep

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We go through several sleep cycles each night and the length of each REM cycles is longer for each new cycle. A full sleep cycle is 90 minutes. After passing through four stages of non-REM sleep, your first REM cycle can last anywhere from one to ten minutes. This number gradually gets higher as the night progresses.

By the end of the night, our REM cycle can be as long as one hour. During this cycle of sleep, we have mixed frequency brain waves. It is believed that we dream during REM sleep. We dream for approximately 2 hours per night and some information suggests that dreams may function to help us process emotions.

Typically, REM sleep takes up about 20-25% of our sleep as adults, and is even as high as 50% of sleep in young babies. During REM sleep our breathing is quick and irregular, our heart rate is increased. Since this is the sleep cycle that is connected to dreaming, people believe that is the reason our eyes move rapidly while we are in REM sleep.

Before scientists used to believe that the body basically shut down during sleep, but now they know that they were wrong. During REM sleep the body is active but the arms and legs are temporarily paralyzed, possibly to stop us from acting out our dreams.

How Many Hours of Sleep Do We Need?

According to the National Institute of Neurological Disorders and Stroke, chronic lack of sleep or low-quality sleep can lead to things like high blood pressure, cardiovascular disease, diabetes, depression, and obesity. This is one of the reasons that we need to make sure that we are getting enough sleep, but ‘enough’ is something that changes as we grow and age.

Many of us have heard that adults need a solid 8 hours of sleep for optimal functioning, but others say anywhere from 7 to 9 hours can be good.

Teenagers and kids need closer to 9 hours or more to help with growth and brain development, while young babies can sleep anywhere from 16-18 hours a day.

Older adults typically get less sleep and can tend to wake up more throughout the night, sometimes because of medications that they need to take.

Related: Best 5 Mattresses for Elderly

Sleep Cycle Apps & Calculators

Understanding Sleep Apnea

To help you accurately calculate what time you should be going to bed in order to wake up revived, there a number of apps and REM sleep calculators that work out what is the best time for you to rise or go to sleep .

Sleep Cycle alarm clock app from Northcube AB  is available for download on both Android and iTunes. It analyzes your sleep and wakes you in your lightest sleep phase. It is an amazing app with many features available.

Online sleep cycle calculator will calculate the exact time you should be preparing for bed so you can feel fresh and alert every morning.

So for instance, if you need to wake up at 6.30 am,  the suggestive time to head to bed is at  9:16 pm  or  10:46 pm  or  12:16 am  or  1:46 am.

To work out your own ideal bedtime, try out the online sleep calculator here for a selection of optimal times to go to bed.


Knowing about what a healthy sleep cycle looks like and what factors can affect our sleep is key to changing unhealthy patterns before chronic lack of sleep starts to get to you. Sleep is very important to our physical and emotional well-being, so making sure we get enough sleep should be a priority.

Smart tech is one great option for learning more about our sleeping habits so we can figure out how to get a full, satisfying night’s sleep. Sleep trackers keep track of things in our environment like loud noises. Precise ones allow us to review our periods of sleep and wakefulness and see how much time we spend in each sleep cycle throughout the night.

Overall, each sleep cycle is 90 minutes and consists of both non-REM and REM sleep. As the night progresses, we tend to spend more time in REM sleep. During REM sleep our bodies are more active, whereas during non-REM sleep our bodies are calmer, cooler and preparing for sleep.

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