What Is Core Sleep vs. Deep Sleep? (2023)

FAQs

What Is Core Sleep vs. Deep Sleep? ›

It typically includes deep sleep (N4) and rapid eye movement (REM) sleep, the most restorative stages of the sleep cycle. Core sleep generally lasts for about four to six hours per night, during which the body and brain undergo critical processes such as tissue repair, memory consolidation and hormone regulation.

Scientists agree that sleep is essential to health, and while stages 1 to 4 and REM sleep are all important, deep sleep is the most essential of all for feeling rested and staying healthy.

An average sleep cycle lasts about 90 minutes. Ideally, you need four to six cycles of sleep every 24 hours to feel fresh and rested. Each cycle contains four individual stages: three that form non-rapid eye movement (NREM) sleep and one rapid eye movement (REM) sleep.

A small chart shows how many minutes you were awake, and how much time you spent in the each of the three basic sleep stages: REM (where most dreaming happens), deep (a restorative phase for mind and body), and core (Apple's term for light sleep, which is essentially the time not spent in REM or deep sleep).

You should aim for about 13 to 23 percent of your sleep to be in these stages. So, if you get 8 hours of sleep, you should be getting anywhere between an hour and just under two hours of deep sleep. However, it's important to note that what time you go to bed can greatly influence how much deep sleep you get.

“Many people wake up tired, even with adequate amounts of sleep. This is likely due to insufficient amounts of deep and REM sleep” shares Dr. Ghacibeh. “So while all stages of sleep are essential to overall well-being, deep sleep is considered the most important stage.”

Stage 3 and 4 sleep, the most restorative stages, are known as deep sleep. We need about one and a half to two hours of deep sleep a night. In stage 3, very slow brain waves called delta waves are interspersed with smaller, faster waves.

There are normally no dreams during this sleep. You feel disoriented when you wake up from this sleep. Deep sleep can last between 1-2 hours which is a quarter of your sleep time. If you want to understand your sleep habits better, you consult one of our sleep specialists in the New York Metro area.

Deep sleep and REM are defined by certain types of brainwaves and physiological states and these devices can estimate these states with about 80% accuracy.

Some people with insomnia experience changes in their sleep cycles and, as a result, may have more stage 1 sleep and less deep sleep. Stress and aging can also reduce levels of deep sleep. Additionally, people with conditions such as schizophrenia and Alzheimer's disease experience less slow wave sleep.

Can Apple Watch detect sleep apnea? ›

Can an Apple Watch Detect Sleep Apnea? Like Fitbit and other wearables, the Apple Watch can detect certain parameters like heart rate and blood oxygen saturation that may indicate sleep apnea, but it cannot comprehensively detect or diagnose sleep apnea.

Heart Rate and Respiration

Some sleep trackers estimate REM sleep in addition to deep and light sleep stages by measuring heart rate.

If you're under age 30, you may get two hours of deep sleep each night. If you're over age 65, on the other hand, you may only get a half hour of deep sleep each night, or none at all. There's no specific requirement for deep sleep, but younger people may need more because it promotes growth and development.

Deep sleep is as important, if not more important, than REM sleep when it comes to physical rest, so keep an eye on this stage if you're tracking your sleep patterns.

The theorized cause behind this link is elevated levels of C-reactive protein (CRP) caused by excessive sleep. Over time, a buildup of this protein places the body and heart in a stressed state, leading to heart disease. This same protein is also known to cause issues with memory.

For healthy adults, spending 20-25% of your time asleep in the REM stage is a good goal. If you get 7-8 hours of sleep, around 90 minutes of that should be REM.

For healthy adults, 20-25% of your total time asleep should be REM sleep. That's where the 90-minute number mentioned above comes from. If you sleep for 7-8 hours, 20% of that equates to roughly an hour-and-a-half, or 90 minutes. However, it's worth noting that the amount of REM sleep we need also declines with age.

If you aren't feeling rested when you wake up, despite getting to sleep at least 8 hours prior, then it might not be the quantity of your sleep that's the problem. It could be your sleep quality that needs some attention. The amount of sleep you get is important, but equally important is the quality of that sleep.

The most common cause of sleepiness is not sleeping long enough. Getting enough restful sleep is crucial for maintaining good health. Research over the past decade has shown that healthy sleep is just as important as exercising regularly and eating a healthy diet.

Why do I never feel rested no matter how much I sleep? ›

The two most likely reasons you're always so tired no matter how much sleep you get are you've got high sleep debt or you're not living in sync with your circadian rhythm. You may also feel sleepy if you're ill, pregnant, or you've got a medical condition like anemia or diabetes.

Experts aren't sure, but there's evidence that suggests dreaming plays a role in supporting brain functions that occur while we're awake, such as processing thoughts, memories, and emotions. So, is dreaming a sign of good sleep? Researchers believe it either reflects or contributes to healthy sleep.

Remembering your dreams doesn't necessarily have anything to do with how restful your sleep is, Dr. Harris says. Instead, recalling those dreams is a lot more likely to depend on a number of factors, from your current level of stress to the medication you're taking.

Alarm clocks, and irregular sleep schedules can result in abrupt waking during dream or REM sleep, and thus result in recall of dreams. Sleep apnea, alcohol, or anything that disturbs sleep can also cause dream recall,” Dimitriu says.

The Apple Watch shows more light or core sleep and less deep sleep than the Fitbit. Tracking your sleep stages and cycles is most accurately done by polysomnography; it's not as simple as monitoring your heart rate all night.

While both brands offer outstanding, high-quality wearables, Fitbit has more budget-friendly options, superior battery life, and better health and fitness tracking than the Apple Watch. The Apple Watch edges out the Fitbit in terms of accuracy, convenience, and extra features, but it may be too pricey for some users.

Do you know how often you snore? Or how loud it is when you do? With SleepWatch Snore Tracking, all SleepWatch users are able to record, listen to, and track their snoring from their Apple Watch or iPhone. You can now listen to your top snores and track where your snoring ranks on a scale from minimal to heavy.

If you're tired but can't sleep, it may be a sign that your circadian rhythm is off. However, being tired all day and awake at night can also be caused by poor napping habits, anxiety, depression, caffeine consumption, blue light from devices, sleep disorders, and even diet.

Taking a melatonin supplement can help increase deep sleep in a few ways. First, it can help to regulate your sleep cycle. This makes it easier for your body to fall into a deep sleep state. Second, melatonin can help to reduce stress and anxiety.

Reasons this might happen include drinking caffeine or alcohol late in the day, a poor sleep environment, a sleep disorder, or another health condition. When you can't get back to sleep quickly, you won't get enough quality sleep to keep you refreshed and healthy.

Does blood oxygen show on Apple Watch during sleep? ›

Blood oxygen measurements only occur during sleep if the Track Sleep with Apple Watch setting is turned on.

Snoring is often associated with a sleep disorder called obstructive sleep apnea (OSA). Not all snorers have OSA, but if snoring is accompanied by any of the following symptoms, it may be an indication to see a doctor for further evaluation for OSA: Witnessed breathing pauses during sleep. Excessive daytime sleepiness.

The irregular rhythm notification feature on your Apple Watch will occasionally look at your heartbeat to check for an irregular rhythm that may be AFib. This usually happens when you're still to ensure a more accurate reading.

Most new wearables also track the sleep stages you cycle through throughout the night. But “in terms of tracking light, deep, and REM sleep, basically all of the devices performed at only a medium level of accuracy,” says Chinoy. Translation: There's only about a 50-percent chance your data is accurate.

During sleep, it is normal for a person's heart rate to slow down below the range for a typical resting heart rate. Between 40 to 50 beats per minute (bpm) is considered an average sleeping heart rate for adults, though this can vary depending on multiple factors.

In its prototype of the feature, Netflix said, it collects data from a FitBit fitness tracking device to determine whether a user is still watching or has fallen asleep. If the user is snoozing, Netflix will turn down the audio and pause whatever the user is watching.

If you wake up at 3 a.m. or another time and can't fall right back asleep, it may be for several reasons. These include lighter sleep cycles, stress, or underlying health conditions. Your 3 a.m. awakenings may occur infrequently and be nothing serious, but regular nights like this could be a sign of insomnia.

Total sleep time, sleep efficiency, and deep sleep (slow wave sleep) decrease with aging; and number of nocturnal awakenings and time spent awake during the night increase with aging.

So does snoring mean deep sleep? No it doesn't. REM sleep becomes very fragmented and interrupted by snoring so snorers aren't able to reach deep sleep. Only frequent, prolonged and severe snores mean possibly obstructive sleep apnea.

Caffeine, benzodiazepines , and opioid pain medications can all affect deep sleep. Caffeine is a stimulant that can reduce deep sleep even hours after you consume it (for example, in a cup of coffee or tea). Benzodiazepines like Valium and opioid pain medications can also reduce deep sleep.

Is 2 hours of deep sleep a lot? ›

The average healthy adult gets roughly 1 to 2 hours of deep sleep per 8 hours of nightly sleep. There are various ways to gauge whether you are, from personal trackers to a sleep study. If you're waking up tired on a regular basis, it's a good idea to talk to a healthcare provider.

Deep sleep describes a particular stage of sleep that is important for waking up feeling refreshed and alert. Although there are no definitive guidelines for how much deep sleep you need, experts say that most adults need between seven and nine hours of sleep each night.

Definition of Core Sleep

It typically includes deep sleep (N4) and rapid eye movement (REM) sleep, the most restorative stages of the sleep cycle.

In adults, 20% of total sleep time is spent in deep sleep (stage 3). Going with the recommended 7-9 hours of sleep each night, that means the average adult needs 84-108 minutes or 1.4-1.8 hours of deep sleep each night.

Core sleep is the essential part of the sleep and is mainly slow wave sleep. This type of sleep is composed of stages 3 and 4 on non-REM sleep (NREM 3-4). Core sleep is obtained during the first three sleep cycles and the remainder of the night sleep is considered optional sleep.

The most important sleep stage is Stage 3, Non-REM or, Delta (Slow Wave) Sleep, it takes up 25% of our total sleep cycle, and it's known as the 'deepest' period of sleep. It's in Stage 3 that sleep is at its most restorative, helping our bodies heal themselves and our minds rest.

Adults generally average 1-2 hours of deep sleep per night, somewhere between 15 and 25% of your nightly sleep. Most of our deep sleep comes in the first sleep cycle of the night, usually 45-90 minutes. Age has a major effect on how much deep sleep we get each night and how much we need.

Researchers concluded the Fitbit was equivalent to the actigraph in almost every way. Yet, when compared with polysomnography, the Fitbit was largely underestimating deep and REM sleep, missing roughly half of the former and a third of the latter. It also overestimated light sleep.

While some people regularly function on short periods of sleep, research mostly agrees that six hours of sleep is not enough for most adults. Experts recommend that most adults need at least seven hours of sleep every night.

Dreaming. A majority of your dreams take place during REM sleep. However, REM is not the only stage in which dreams occur — that's actually a common myth about sleep. That said, the dreams you experience in REM sleep are usually more vivid than non-REM sleep dreams.