Deep sleep is crucial to our health and well-being. Numerous groups, including the American Academy of Sleep Medicine (AASM), recommend adults get 7-9 hours of overall sleep each night, including light sleep, deep sleep, and REM sleep. However, some analysis has found that 31% of grown-ups aren't getting the correct amount of needed sleep . This raises the question: how much deep sleep do you need, and what is deep sleep's role compared to other types of sleep, like REM and light sleep?
Analysis from groups like the AASM is now being joined by top brand names, like wearable activity tracker Fitbit, helping us understand sleep at deeper levels than before. In 2018, Fitbit released data from over 6 billion hours of users' sleep. Their analysis found that while women get roughly 30 minutes more sleep than men each night, neither gender gets their recommended sleep, falling short of the 7-hour mark by 10 to 34 minutes on average . This data is crucial in understanding our sleep habits and how much REM sleep and deep sleep we actually get.
We need to understand how sleep and our bodies work to get more sleep. Keep reading to discover more about deep sleep, the entire rest cycle, and other must-know information like what stage of sleep do you dream and how long is a sleep cycle.
Sleep isn't one long slumber each night. Instead, it's a series of four to six nightly sleep cycles. Each cycle comprises four stages, with the intensity of the sleep growing from light to deep to vivid–with phase periods increasing each sleep cycle per night. Understanding the stages of NREM sleep and REM sleep is crucial for recognizing how much core sleep vs deep sleep you need.
The four stages of sleep are :
1. Stage 1 (NREM or N1): Initially lasting about 1-7 minutes of light sleep that eases us into sleep.
2. Stage 2 (NREM or N2): 10-25 minutes of light sleep, slightly more significant than N1, further subduing our consciousness.
3. Stage 3 (NREM or N3): Deep sleep lasting for 20-40 minutes where the body performs several essential therapeutic processes, including physical recovery and memory consolidation. This is often referred to as core sleep, where brain waves slow, and heart rate and breathing decrease.
4. Stage 4 (REM sleep): 10-60 minutes of deep, vivid dreaming and further cognitive function repairs and rejuvenations. This is the phase of sleep where rapid eye movement (REM) and brain activity increase.
What is Deep Sleep?
Deep sleep, also known as slow-wave sleep, is a critical component of our body and mind, serving as a period to rebuild and even enhance ourselves  . During deep sleep vs REM sleep, the body is in a state of relaxation, allowing for physical repair and recovery. It's a time when the brain drains toxins and performs essential maintenance.
Deep sleep occurs within or around one hour into our nightly sleep. The first sleep cycle is the most substantial period of deep sleep in a night, with the duration lessening as someone sleeps. Many core body operations decrease or slow during deep sleep, including breathing and heart rates. With our bodies in a deep state of relaxation, core functions slow down. During this time, waking someone from a deep sleep can be difficult and could leave the person in a foggy head state.
Deep sleep is crucial in restoring our energy levels, repairing essential bodily and mental functions, boosting our immunity, and much more. Learning and memory are particularly affected by deep sleep, as this stage gives the mind time to process and preserve any new information gathered during the day. This rest period helps us understand crucial information, including job tasks and critical personal life details.
How Much Deep Sleep Do You Need Each Night?
Recommended sleep is determined by several factors, with age being critical. Adults are typically recommended to sleep seven to nine hours per night. If the person sleeps this length and experiences four to six complete sleep cycles in a night, they should spend 20% of their rest in a deep sleep.
However, numerous factors impact how much deep sleep you'll likely receive. Age continues to play an important role. As we mature from young to older adults, we experience less deep sleep and more stage 2 light sleep. Your sleeping habits will also be a significant factor. To recuperate from a case of sleep deprivation, your body will self-regulate itself with additional deep sleep. On the other hand, people who frequently nap typically experience less deep sleep at night because their deep sleep is partially satisfied throughout the day . Understanding how much deep sleep is normal and how much REM sleep is needed can help tailor your sleep habits for better rest.
Benefits of Adequate Deep Sleep
We often hear that it's quality, not quantity, that matters. When we get the right kind of deep sleep, our body and mind begin to experience a world of short- and long-term benefits, including :
- Physical Repair and Recovery: There's a reason why R&R is short for rest and relaxation. Sleep helps the body and mind repair everything from our blood vessels to our immune system and numerous critical bodily functions.
- Enhance Brain Function: Stage 3 is when our brains process and consolidate memories, enhancing our learning and fueling our creativity.
- Improved and Regulated Moods: Deep sleep helps keep our moods healthy, with quality rest serving as a stabilizer that helps combat stress and anxiety.
- Lowered Disease Risk: A lack of adequate sleep increases the chances of contracting several diseases and disorders, including stroke, obesity, and dementia.
- Brain Drain (The Good Kind!): Dr. Maiken Nedergaard and his colleagues at the University of Rochester discovered that the brain has a drainage system that removes toxins. This system works at double speed when we're at rest.
- Controls Glucose Metabolism and Blood Sugar: Glucose and blood sugar levels are kept in check, in part, by a proper night's rest. Without the required sleep, our glucose metabolism can become disrupted, leading to potentially higher odds of developing diabetes.
Risks of Not Enough Deep Sleep
Despite seemingly everyone understanding that they need the right amount of rest, notably deep sleep, many of us fall short of getting our needed slumber. No matter why that may be, our lack of sleep may increase the odds of developing short-term symptoms and potentially long-term conditions.
A lack of sleep can create an array of profound adverse impacts on our minds and bodies. If we don't prioritize our rest, we run the risk of encountering numerous conditions, such as:
- Diminished focus
- Anxiety and other mental health concerns
- High blood pressure
- Decreased cognitive functions
- Decreased motivation
- Slow healing, recovery or rejuvenation
- Sexual dysfunction
- Diminished immune system functionality
Why Might I Be Waking Up Tired?
Waking up tired despite getting a seemingly full night's rest is one of the more frustrating ways to start the day. Millions, if not billions, experience this start to their day regularly. The continued happening may point to a lack of deep sleep.
While a dearth of deep sleep is likely partially or entirely to blame, other factors may also be leaving a person feeling exhausted after sleeping the recommended amount of hours, including:
Sleep Disorders: Various sleep disorders and medical conditions may cause a person to lose sleep or struggle to fall asleep. Conditions and other factors that can lead to sleep disorders include :
- Obstructive sleep apnea
- REM sleep disorder
- Older age
- Traumatic brain injuries
Medications: Certain medications could disrupt sleep through several side effects, including insomnia, body pains, involuntary movements, and much more.
Shifting Sleep Schedules: Disruptions to the body's circadian rhythm can cause fragmented rest, which is linked to declining slow-wave sleep.
Brain Damage: Studies have indicated that injuries to certain parts of the brain may impact sleep. Affected areas include the hippocampus, an integral part of the brain's ability to produce deep sleep's slow delta waves. Without these waves, the body cannot restore brain health or memory functions as required.
Anyone experiencing morning fatigue should contact a trusted medical professional to determine the cause and any possible treatment options. Addressing these concerns early ensures the best odds of a good night's sleep and long-term positive health.
How to Get More Deep Sleep
Deep sleep is a critical component of maintaining our physical and mental health. While most adults understand the importance of getting seven to nine hours of sleep each night and adequate deep sleep, achieving that level of rest is often difficult or impossible.
Regularly missing the amount of needed sleep can lead to health risks that could affect you for days, months, or even a lifetime. Don't wait to address the issue. If you struggle to get the needed rest regularly, contact a medical professional to schedule an analysis of your sleep, overall health, and daily habits.
Sometimes, people may need medical assistance or prescribed medications to sleep. In many cases, people can improve their sleep with a few small but substantial changes, including:
- Developing and sticking to an established sleep schedule: Sticking to a dedicated schedule helps minimize or eliminate circadian rhythm disruptions.
- Sleep Environment: Quiet, dark, and cool places are ideal sleep settings.
- Exercise: Physical activity puts our bodies in motion and promotes better sleep afterward
- No late-night caffeine: Limiting or eliminating caffeine during the late afternoon and evening helps minimize sleep disturbances
- Warm bath or shower: Increasing the body's temperature produces a natural cooldown in the body, which can aid in creating an ideal sleep setting
- Diet adjustment: Avoid late-night eating and heavy meals. Try to stick to a high fiber, low saturated fat diet to promote better sleep
- Music and beats: Listening to calming music or frequency waves created by binaural beats may promote deeper sleep
With every person having unique medical needs and personal preferences, it's always best to consult a medical professional to assess the possible causes and solutions to your deep sleep difficulties.