People typically go through five or six sleep cycles every night. If your baby’s sleep cycle is 20 mins, then a 20 min sleep isn’t a “cat nap” or “junk sleep” it is a full sleep cycle. Use the 90-minute sleep rule. It can last anywhere from 10 to 20 minutes, and you can be jolted. Slow wave or deep sleep is a stage in the sleep cycle needed for proper brain function and memory. FAQs. Though micro-sleeps are usually around 20 minutes, not 5. Sleep Phases and Stages. Go to another room and read or do other quiet activities until you feel sleepy. Take naps in the early afternoon. FYI everyone, the 90 minute thing is a very rough estimate. Some people completely or partially wake up after the sleep cycle ends, while others stay asleep until morning. Below we’ll explain why this is the case, take a look at the benefits of napping, and help you. to 4 a. We ALL wake briefly between sleep cycles and a baby’s sleep cycles at nap time will be about 30-45 minutes. The average healthy person takes around 10-20 minutes to fall asleep, but sleep latency naturally varies from person to person. The average nap is about one hour, or 60. m. Babies don’t have 90 minute sleep cycles, like adults do. Over one or two cycles that's basically irrelevant, but over 4-5 that 20-30 minute window can make a difference. In the first sleep cycles of the night, more time is spent in non-REM sleep. The duration of REM sleep increases from 10 minutes in the first cycle to up to 50 minutes in the final cycle; note that slow-wave (stage IV) sleep is attained only in the first two cycles. Only use your bedroom for sleep. Stages Four and Five: Deep non-REM sleep, or quiet sleep. It. “By adulthood, most healthy people need 7 to 8. The best length for a nap is 10-20 minutes. This occurs between the end of one sleep cycle and the beginning of a new one. Set an alarm. Excessive daytime sleepiness may. Generally, a person enters a REM sleep stage after they’ve been. Sleep studies use sensors to record eye movements and brain activity,. This strategy generally works well for students who need to nap before and after their classes. It is sometimes called the ultradian sleep cycle, sleep–dream cycle, or REM-NREM cycle, to distinguish it from the circadian alternation between sleep and wakefulness. The key to successful power napping is its length. The sleep calculator recommends when to go to sleep in order to wake up feeling refreshed. Each phase and. After the first REM cycle, you start a new sleep cycle and go back into stage 1 or 2, and the cycle starts over. View Source. If you sleep longer than 20 minutes, you risk going into a deeper sleep and waking up groggy. It suggests sleeping time based on the stages of sleep, which will help to avoid waking up in the middle of a sleep cycle. This can make a person feel extremely groggy and experience poor cognitive performance. Be tired enough for it so that it doesn't take 20. Some studies suggest that a 20-minute nap has the energy-boosting equivalent of more than 200 mg of caffeine, or two cups of. Aim to nap for only 10 to 20 minutes. You are lightly sleeping, drifting in and out. The 90-minute cycle takes effect (if it hasn’t already). The average adult cycles through each stage of sleep several times per night, with each sleep cycle lasting approximately 90 to 120 minutes Trusted Source Merck Manual First published in 1899 as a small reference book for physicians and pharmacists, the Manual grew in size and scope to become one of the most widely used comprehensive medical. Adults’ sleep cycles last about 90 minutes from the beginning to the end, while babies’ sleep cycles last 45-60 minutes. 5 to 12 years: no nap needed if they’re getting the recommended 10 or 11 hours of sleep per night. Developing a sleep routine that allows you to get 5-6 cycles in and wake up at the end of a cycle will allow you to wake up feeling better. If you get 7-8 hours of sleep, around 90 minutes of that should be REM. 11:15 p. One thing we really like about this formula is how reasonable/attainable it is. the first stage lasts for about 5-10 minutes, the second stage lasts for about 20 minutes, and the third stage lasts for about 30 minutes. There was an average of two REM sleep episodes per sleep-wake cycle. But any sleep is better than not at all — even if it. Each complete sleep cycle takes from 90 to 110 minutes. Alter your sleep schedule gradually. Giving yourself a full sleep cycle (90 minutes) can help you retain certain skill you’ve just learned, but for recovering from fatigue a 15-20 minute nap is ideal (and some research suggests a. After that, baby transitions into deeper, or non-REM, sleep. A longer power nap can be helpful if timed so that a person wakes up at the end of a sleep cycle, which lasts about 90 minutes. Each additional REM stage gets longer throughout the night. During this stage, muscles contract and expand, and the breathing rate decreases. Biphasic sleep is divided into two parts. The optimal nap length can vary from person to person for any number of reasons--age, career, lifestyle, schedule, etc. All the while, your brain is busy forming, organizing, and storing memories. The length and pattern of sleep cycles also vary based on a person’s age. REM sleep may only last one to five minutes in the first cycle, and it gets longer and longer with each cycle. The longest periods of this stage occur during the first several sleep cycles. 2 hours; and 80-year-olds take 19 minutes to fall asleep and will sleep for 5. During the second part of the night we spend more and more time alternating between stages 2 & REM sleep. Overall, it accounts for more than 50% of sleep in adults. Uberman Sleep Cycle — Similar to the Dymaxion Sleep Cycle, the Uberman only requires two hours of sleep per 24 hour period. Non-24-Hour Sleep-Wake. It also allows 15 minutes to sink into sleep and 15 minutes to wake up. If you experience increased awake time during the night, resist the urge to sleep in. Quiet reading, low-impact stretching, listening to soothing music, and relaxation exercises are examples of ways to get into the right frame of mind for sleep. , the sleep cycle calculator says you could achieve about six sleep cycles through nine hours of sleep if you go to bed at 10 p. Most of these consist of utilizing naps to break up your sleeping and waking cycle in a. 6 to 12 years: 9 to 12 hours. To wrap up – the 90 minute sleep cycle plays a crucial role in ensuring optimal sleep quality and recovery. Morning daylight, even for just 15-minutes, improves the quality of your sleep. So, if you can squeeze in 90 minutes, and fit in a few naps later in the day, you may be able to catch up on the rest you need to function. Non-REM sleep begins, eventually moving into slow-wave sleep, or deep sleep. You go through all three phases before reaching REM sleep. During your REM sleep cycle, your eyes are darting around and “seeing” different things. During this stage: eye movements become. This may not involve a consolidated period of sleep at night. When you sleep, you cycle through two phases of sleep: rapid eye movement (REM) and non-REM sleep. An adequate night's sleep for an adult is about seven or eight hours. 9:45 p. There are three phases of non-REM sleep. You may wake up briefly between cycles. Stage 2 non-REM sleep. “There’s an idea that everyone sleeps in 90-minute cycles but that’s an average, not a rule,” says Winter. The sleep cycle does not proceed directly from NREM to REM sleep, it progresses through the stages of NREM sleep from light to deepDr. People who have lost their sight and cannot coordinate their natural wake-sleep cycle using natural light can stabilize their sleep patterns by taking small amounts of melatonin at the same time each day. The calculator will tell you when to go to sleep for recommended 4 to 6 sleep cycles. Spindles play an essential role in processing and consolidating memories. Taking a brief 20-minute nap can help you feel more rested and alert when you wake up. Dr Raj went on to explain that if you wake. When a baby is born, he or she will sleep for 14 to 20 hours per day. Exercise 20 to 30 minutes a day but no later than a few hours before going to bed. 5 hour nap with 4-5 20 minute naps, all of which have equal amounts of time in between each nap. There was an average of two REM sleep episodes per sleep-wake cycle. REM Sleep. Enjoying a coffee 15-20 minutes before lying down helps to prevent the brain from absorbing adenosine, a chemical that causes drowsiness and sleep. The ideal length, according to the scientists, is 20 to 25 minutes. Sleep Latency. Sleep cycles are 90-minute sequences which move through the four different sleep stages and each sleep stage lasts between 5-15 minutes. 80. The Average Time It Takes to Fall Asleep. Taking a REM nap means you will complete the sleep cycle for once. Keep naps 20-30 minutes, as longer naps can lead to sleep inertia, leaving you feeling groggy and sluggish. Professional Yacht Racers (particularly Single Handed racers) are an example of micro-sleep users. Vivid dreams may occur during REM sleep. Every time you fall asleep, your body starts going through a 5-stage sleep cycle. The final cycle of stage R may last roughly between 30 to 60 minutes. Considering 90-minute cycles: 6 sleep cycles = 9 hours. Each stage progresses sequentially through light sleep, deep s/leep, and REM cycles which repeat on 90-110 minute intervals. 13 to 18 years. Set an alarm. Sleep is a crucial part of the daily activity patterns of mammals. adults have taken a nap in the past three months. Most experts recommend that healthy people who are not sleep-deprived take short naps, defined as ranging from five to 20 minutes. When you sleep, you cycle through two phases of sleep: rapid eye movement (REM) and non-REM sleep. Stage 4 ( REM sleep) lasts 10 to 60 minutes. Sleep time is the number of hours that we use to rest and regenerate the body and mind. Note: This table factors in 15 minutes to fall asleep, followed by 90-minute sleep cycles. An average person needs 5-6 cycles to feel fully regenerated in the morning. So, Breus explains, five sleep cycles come out to 450 minutes, plus the roughly 20 minutes it takes to fall asleep. Between the ages of 20 and 80 the length of sleep onset increases by less than ten minutes on average. Duration: 90 minutes (a full sleep cycle). Don’t leave the timing to chance, because chances are you’ll wake up somewhere outside the recommended nap lengths. Narcolepsy: A sleep disorder that causes individuals to uncontrollably fall. So, 10-20 minute naps should be just the ticket! It a actually does, given that you are properly trained. As you continue sleeping, these stages get shorter, and. There are typically five stages that make up a baby’s sleep cycle: Stage One: Your baby feels drowsy and starts to drift off to sleep. 5 hours of sleep. For example, an individual may take six 20. Speaking from personal experience, I found that setting an alarm for 1 cycle is rarely reliable, but setting one for 3 cycles worked well for me; when I was in high school I used to randomly jerk awake somewhat regularly. Usually, sleep cycles fall into 90-minute patterns. Researchers say a 20 minute nap is the best length. To gradually adopt a new sleep schedule, you can make adjustments in 15 or 30 minute increments over a series of days. So try one of the apps or alarm clocks others have mentioned (or if you only have a crappy flippy phone like me and don't intend to get an. In general, each cycle moves sequentially through each of the 4 stages of sleep: wake, light sleep, deep sleep, REM, and repeat. Another genius who utilized napping during the day was Leonardo Da Vinci. By the time you wake up the caffeine will have. After a little bit of sleep, whether that’s more of a catnap (baby wakes up after 20 minutes) or after one sleep cycle at night (45 minutes after going to bed) some of the sleep pressure is removed. Below we’ll explain why this is the case, take a look at the benefits of napping, and help you. That’s because sunshine calibrates the body’s internal “circadian” clock. It is not only possible to incorporate the same soothing technique into your bedtime routine, but also to accommodate your child’s specific preferences. Why? 90 minutes is the length of one full sleep cycle, which includes all the light and. NREM-2. 5, 90-minute cycles. M. Catnapping is one of the most common complaints among new parents who visit this site. “There’s an idea that everyone sleeps in 90-minute cycles but that’s an average, not a rule,” says Winter. Each sleep cycle typically takes lasts about 90 minutes, but it can extend to as long as 120 minutes, according to Al-Sharif. Stage 3 An average sleep cycle lasts about 90 minutes. The language is quite complex to understand in general. Because this seems the most restrictive, it’s best for those who can follow a rigid polyphasic sleep schedule. It's the most restful stage, where brain waves and heart. To make sure your power nap doesn’t turn into a marathon sleep sesh, set an alarm to wake you after 20 or 30 minutes. During stage 2 sleep: You become less aware of your surroundings Your body. Nathaniel Kleitman is considered the father of modern-day sleep science. The pair later discovered that the brain also cycles through periods of activity and rest when awake. 2. 9:30 AM –. This unconventional sleep cycle may have given. Taking an additional hour or more beyond the average latency cuts short the total sleep duration for the night. “A full sleep cycle is typically around 90 minutes and throughout that time we are cycling through light and deep sleep phases,” she explains. Polyphasic-sleep. What are sleep cycles? A sleep cycle is the cycle between non-rapid-eye-movement (NREM) sleep and rapid-eye-movement (REM) sleep. 20 minutes of exercise, 20. One normal sleep cycle, including REM sleep, takes about 90 minutes. This is hard, but necessary. Deep sleep occurs multiple times throughout the sleep period, but factors like insomnia, stress, and aging can affect duration of deep. Five cycles are about 7. Too little is… well it’s just not enough. 20 minute sleep cycle: My baby boy only naps for 20 minutes unless I hold him, been like this since 10 weeks old. Birth to 3 months: 14 to 17 hours. periodic phsyiological fluctuations including annual cycles, 28 day cycle, 90 minute cycle and 24 hour cycle. m. However, for most babies older than 2-4 months, normal naps fall within the ranges of normal baby sleep outlined here. , and then take three 20 minute naps, one at 9 a. Most adults aim for 5-6 complete sleep cycles (7. As NREM sleep progresses, the brain becomes less responsive to external stimuli, and it becomes increasingly difficult to awaken an individual from sleep. 5 hours 6 cycles is 9 hoursOne sleep cycle lasts an average of 90 minutes: 65 minutes of normal, or non-REM (rapid eye movement), sleep; 20 minutes of REM sleep (in which we dream); and a final 5 minutes of non-REM sleep. 7 a. Your sleep cycles. Everyman 2: This is another adaptation of the original Everyman sleep cycle. We need all the stages of a 90-minute sleep cycle but deep sleep - which only make up around 20 per cent of total sleep - is thought to be especially beneficial for physical and mental health. Brain-wave patterns showed that seals took short (less than 20 minutes. The Sleep Cycle, Explained. . Over one or two cycles that's basically irrelevant, but over 4-5 that 20-30 minute window can make a difference. Intelligent snooze lets you snooze through your wake up phase. 20 minutes. Stage N2 lasts from about 30 to 60 minutes. Each stage has a different duration, and for some of the stages, their duration will change throughout the course of the night. After the first REM cycle, you start a new sleep cycle and go back into stage 1 or 2, and the cycle starts over. When you’re ready to nod off, start. Different systems of the body follow circadian rhythms that are synchronized with a biological. Regularly waking up for at least 20 to 30 minutes at night might be a sign that you have middle-of-the-night insomnia, Dr. The average length of the first NREM-REM sleep cycle is between 70. The brain has a dual process responsible for regulating sleep-wake states. One cycle normally takes about 90 to 120 minutes before another begins. The power nap is 10 to 20 minutes long. “What’s interesting is that some signatures of. The 90-minute rule is based on this process. A nap 50 minutes or longer demonstrates your baby’s ability to transition from one sleep cycle to the next. But young babies spend only a minority of their time in quiet sleep — approximately 20 minutes per sleep cycle (Grigg-Damberger 2017). Sleep studies use sensors to record eye movements and brain activity, which are used to. Duration: 10 to 20 minutes so you don’t move into a deep sleep stage. During. Therefore, the length of each sleep cycle is about 100 minutes, so the initial REM period is only about 10 minutes. There are many different polyphasic sleep schedules, according to the Polyphasic Society, but one of the most popular. The 45-minute nap is really common, and there are a few specific reasons why: Forty-five minutes is not a coincidence; it is exactly one sleep cycle for a baby. In children and adolescents, REM sleep declines to about 20 to 25 percent of total sleep time. For example, during sleep, on average our brains go through a 90-minute cycle of rest known as non-REM sleep. 20 minute Nap vs. Consider how long it takes to fall asleep and add it to the previous result. It is much easier to fall asleep if you are at ease. THIS PAPER is intended to draw attention to a basic biological cycle—the 90-minute "sleep-dream cycle"—to define and describe the cycle, and to present some data from studies specifically investigating this variable. The first 20 or so minutes of a nap are light sleep, or REM sleep. 30pm. 16-20 hours: 50/50 split of sleep between night and day, waking every 2-4 hours to feed. m. More commonly referred to as the ultradian (alt-ray-dee-in) rhythm, Kleitman suggested that our sleep and wake cycles occur in 90-minute intervals. Each night, you have between four and six sleep cycles. [1] To get the most out of a nap, follow these tips: Keep naps short. Initial sleep cycles contain more slow-wave sleep, whereas cycles in the latter part of the night include more REM sleep. Short naps of less than 90. These 90-minute sleep cycles result in more or fewer sleep cycles per night, depending on how long you sleep. Make it early. 30-90 minute naps may be beneficial for athletes who are sleep deprived and who need optimal muscle growth and repair. Set an alarm. When we study the usual criteria of sleep like REM, amount of sleep, number of awakenings at night,. During REM sleep, brain activity increases substantially. [1] Here are some basic tips for healthful napping: Sleep for no longer than 30 minutes: The ideal nap duration is around 20 minutes and should be no longer than 30 minutes. This is when your eye movement and muscle activity slow down. Everyman: A long sleep time of around 3 hours with approximately three 20-minute naps throughout the day. , and. A 1979 study by Feinberg and Floyd reported that, for the majority of subjects (around 70%), sleep cycles were up to 20 minutes longer or shorter. Most people have a regular sleep cycle of about 90 minutes. As a result, this instantly lowers your heart rate and blood pressure, which will make it easier to fall asleep. , you might expect to wake at 4:00 a. This clock controls a number of processes, including sleep-wake cycles. According to studies, the best length for a nap for adults is 10- 20 minutes and 90 minutes. m. For most adults, seven to nine hours of sleep per night is what’s recommended, but there’s no “one-size-fits-all” when it comes to napping. Sleep guidelines by age. Biphasic (or diphasic, bifurcated, or bimodal) sleep refers to two periods, while polyphasic usually means more than two. Stage 2: Stage 2 follows stage 1 and lasts about 10 to 25 minutes. It seems that if you wake up then, you’ll feel more rested. This cycle consists of taking six 20-minute naps, evenly distributed, throughout your day. You can fit five complete 90-minute cycles during that time. You either sleep for 15 to 20 minutes or a full sleep cycle of 90 minutes to make the most of your nap time. Da Vinci created what is called the polyphasic sleep process, or, the Da Vinci Sleep Schedule. This hormone is secreted in higher amounts at night. On a night when you get the recommended seven to nine hours of sleep, you’ll cycle through each of these stages several times. The dog has a propensity to sleep over a 16-hr interval. A healthy adult doesn’t need to nap, but can benefit from a nap of 10 to 20 minutes, or 90 to. If you work a daytime schedule, a brief (<20-minute) nap is recommended. , 2 p. The exact number of hours, or sleep cycles, you need at night will vary depending on a number of factors, including: Your age, as children and younger adults tend to need more sleep; Your gender, as women tend to need 20 more minutes on average than men;Deep sleep lasts 20 to 40 minutes 11. If you are already well-rested and you take a 90-minute nap, where you complete an entire sleep cycle, it may make it harder to fall asleep at night time. Time your nap with your natural sleep cycle, so you don’t wake up feeling groggy. The composition of a sleep cycle changes throughout the night too. This means we should. Giving yourself a full sleep cycle (90 minutes) can help you retain certain skill you’ve just learned, but for recovering from fatigue a 15-20 minute nap is ideal (and some research suggests a. Each night, you have between four and six sleep cycles. On average, you may need 10-20 minutes to fall asleep, and it takes about 90 minutes to go through each sleep cycle. Here are polyphasic cycles: Uberman Cycle: 20 to 30 minute naps every 4 hours, resulting in 6 naps each day. It's also important to work with your sleep cycles – you don't want to be waking up in the deep sleep part of your cycle, as this will make you feel groggy (known as sleep inertia). migration, hibernation and Seasonal Affective Disorder (S. The 90-minute rule. So. Sleep occurs in cycles, with a rapid eye movement (REM) sleep stage about every 90 to 120 minutes. Infants: 12-15 hours. This means when you wake up you will. ”. 30pm. The first half of the night is when we tend to get the most N3 sleep, with each 20-40 minutes session getting shorter as the night continues. The Uberman is a polyphasic cycle that consists of 6 to 8 equidistant naps across the day, each lasting 20 minutes. Deep sleep (or slow-wave sleep) Starts about 90 minutes into sleep cycle: About 10 minutes: About 30-60 minutes: About 20-40 minutes: First REM stage is about 10 minutes. Because sleep cycles and recommended sleep times vary by age, we took that into account when approximating the best times for you. Sleep Latency. Referred to as a baby’s sleep cycle, this pattern repeats about every 60 minutes over a period of several hours. Generally, these daily ultradian cycles involve alternating periods of high-frequency brain activity (about 90 minutes) followed by lower-frequency brain activity (about 20 minutes). Start Keeping a Sleep Diary. Ernest Hartmann, MD described the 90-minute sleep cycle as a basic or general 90-minute cycle of our night’s sleep and is determined by electroencephalogram and REM criteria. In humans, this cycle takes 70 to 110 minutes (90 ± 20 minutes). Avoid nicotine and alcohol in the. female menstral cycle. 5-hour nap in the middle of the day. It receives both “cortical” and “subcortical” inputs. The composition of a sleep cycle changes throughout the night too. 4. muscle tension. The length and pattern of sleep cycles also vary based on a person’s age. Older Babies’ Daytime Sleep Cycle and Schedule A older baby’s day typically starts between 6 to 7am, but they’re still squeezing two to three naps into their daily routine that generally last an hour or two, max. When you hit the snooze button, you're awake, and as the alarm turns off, your brain then drifts back into sleep. Most people go through four or five cycles per night (assuming they get a full eight hours of sleep). 3 days each year, on average. If you nap in the morning, the sleep consists primarily of light NREM (and possibly REM) sleep. So instead, the typical 50-55 minute newborn sleep cycle includes only about 20 minutes of quiet sleep. m. NREM-1. Dr Raj went on to explain that if you wake. All your body functions right from blood pressure, eye movements,. Exercising for at least 20 minutes per day at least four or five hours before bedtime also improves sleep quality and can help. One sleeps around 5 hours each night, with about a 1 to 1. A 6 nap schedule (2-hour total sleep) will consist of a nap every 4 hours, it will have a 2 hour BRAC (Basic Rest Activity Cycle)and a 4 h rhythm. consciousness. The organized and structured process of normal sleep is known as sleep architecture. Midday Nap Sleep Schedule: With this biphasic sleep schedule, people swap the long siesta for a short, 20- or 30-minute nap during the day. The general advice is that you either take a short nap (20 minutes or so) so that you never make it to the deeper non-rem stages of sleep or take a 90 minute(ish) so that you complete one sleep cycle. The cycle starts over every 80 to 100 minutes. I’m at my wits end I feel like his on me all day. Non-REM and REM sleep are two categories of sleep that are vastly different. How many 90-minute sleep cycles should I get? The number of 90-minute sleep cycles you should get depends on your individual sleep needs. Older women are also more likely to report higher levels of sleepiness, and to sleep 20 minutes less per night. our awareness of ourselves and environment; began as sole topic of psychology. Here’s how much kids and. The cortex detects the onset of being tired, or cognitive functioning being affected by lack of rest. It a actually does, given that you are properly trained. Read through this guide to sleep cycles and stages to better understand how sleep works and what you can do to make it the best rest ever. 10 to 20 minutes is the perfect nap length. Sleeping for an entire sleep cycle will help you feel refreshed and more alert, while also ensuring that you do not awaken in deep sleep. Have you ever heard of someone suggesting a 20 minute power nap? This is because it gives you some light rest before entering REM sleep. Aim for a 10-20 minutes nap to feel refreshed. Everyman cycle: 3. To make sure your power nap doesn’t turn into a marathon sleep sesh, set an alarm to wake you after 20 or 30 minutes. For many sleepers, that magic moment. allowing 15 minutes to fall asleep. FYI everyone, the 90 minute thing is a very rough estimate. Napping for longer than 30 minutes may leave you feeling groggy. If you normally wake up at 10 A. Stay away from electronic screens for at least half an hour before bed. For this reason, I advise napping for 20 minutes. At 20 months, we want to aim for 2-3 hours of daytime sleep. • Duration increases with each sleep cycle and averages 20 minutes. Leonardo da Vinci's sleep schedule included 20-minute naps every four hours. Polyphasic sleep is the practice of sleeping during multiple periods over the course of 24 hours, in contrast to monophasic sleep, which is one period of sleep within 24 hours. • Stage is typified by rapidly moving eyes, fluctuating heart and respiratory rates, increased or fluctuating blood pressure, loss of skeletal muscle tone, and increase of gastric secretions. These natural processes respond primarily to light and dark and affect most living things, including animals, plants, and microbes. Avoiding liquids reduces your chances of needing to get up to use the bathroom in the middle of the night. Stage 3 (N3) Stage 3 is also known as the deep sleep stage. I try to leave her for as long as possible until she starts screaming and then I will go and. And if it’s too bright, there’s no melatonin to help promote sleep. ” That time could take even longer, however, if you do other activities in bed like. Napping for longer than 20 minutes risks going to deep into the sleep cycle, which can result in feeling more tired and groggy, rather than rested. Active phase: In the active phase, REM sleep. Multiply 90 minutes (each cycle time) by five (the number of sleep cycles per night) to get 450 minutes or 7.