The Science of Napping
Simple guidelines to nap like a champ
By Dr. Dan Gartenberg
Last Updated: July 11, 2026
Napping Overview
How long should my nap be? What is the perfect nap time of day? How do I get a deep nap that doesn’t leave me feeling groggy? Can naps make up for a lack of sleep?
These are common questions that have a scientific answer. There are different types of naps that are optimal based on your sleep needs, anticipated sleep needs, and the time of day.
Napping is one of the best (and easiest!) things that you can do for your health, work performance, and general well-being. Scientific evidence has shown that napping can improve waking performance and alertness, even after a normal night of sleep. It is the best way to counteract that grogginess that occurs when you’re sleep deprived or feel tired at 4 pm when your circadian alertness decreases.
Napping can be immensely helpful to your work life and your day, but napping the wrong way can leave you feeling drowsy and grumpy. Keeping the following guidelines in mind can help you avoid these negative side effects:
1) Never nap if you have problems falling asleep and staying asleep
Napping can be a great way to optimize consciousness and performance. However, if you have problems falling asleep and staying asleep, there is consensus in sleep science that you should never nap. The reason for this is that napping will reduce the buildup of adenosine, which is a neurotransmitter that increases throughout the day in order to make the brain tired. In other words, if you nap, you will be less likely to be tired when you ought to go to bed. This can make problems falling asleep and staying asleep much worse. As shown in the graph below, taking a nap can flatten your circadian rhythm, which can be counterproductive to health and well-being. Disclaimer: If you drive for a living, operate heavy machinery, or have a job that could cause serious accidents you can ignore this device and make sure you are fully rested in any way possible to complete your job.
2) The ideal time for a short nap is under 30 minutes or over 90 minutes
In general, it’s best to avoid waking up during the deep sleep phase. The danger zone of napping is between 30 to 80 minutes. If you wake up during this window, it’s likely that you’re waking up during the deep sleep cycle. This will leave you feeling groggy and confused when you awaken, keeping you from feeling refreshed.
3) Try to nap in early afternoon during your circadian dip
It’s also best to nap when the circadian component of sleep is low so that it doesn’t take long to fall asleep. Late afternoon naps can keep you from falling asleep that night.
4) Different types of naps are appropriate for different circumstances
Replacement Naps are best for when you are sleep deprived, Appetitive Naps and Micro-naps help to improve performance, and Prophylactic Naps are used in preparation for sleep deprivation
Replacement Naps / A Full Sleep Cycle Nap
Replacement Naps are taken to make up for previous sleep loss. These naps should be long to ensure the restorative powers of a complete sleep cycle. For example, if you are sleep deprived and you feel tired, a longer nap of about 90 minutes may be appropriate. A 90 minute nap means that you will likely go through an entire sleep cycle. 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.
Appetitive Naps
If you are not sleep deprived, then shorter naps of less than 30 minutes are best. These are called Appetitive Naps. In a recent study, people who took less than 20-minute naps in the mid-afternoon experienced increased work performance and rated themselves as being less tired.
Prophylactic Naps
The best time to take a nap can also be influenced by how long you plan to be awake. If you know that you are going to stay awake for a long period of time, taking a nap prior to this period of sleep deprivation can improve your performance. These types of naps that are taken in advance of sustained wakefulness are known as Prophylactic Naps. The key to these naps is to sleep before the period of sleep deprivation. Taking prophylactic naps can help keep you alert and focused.
Micro-nap
A micro-nap is a very short nap that lasts between 1 and 6 minutes. It is a great way to quickly recharge your batteries and boost your energy levels. Micro-nap are best for those who want to quickly regain their focus and energy levels without feeling sleepy or tired. These naps are helpful for a cognitive boost if you are already getting a healthy amount of sleep.
Caffeine-nap
A caffeine-nap, also known as a coffee nap, is a strategy for combating fatigue that involves consuming a caffeinated beverage, such as coffee or tea, and then immediately taking a short nap. The idea behind the caffeine-nap is that the caffeine takes approximately 20-30 minutes to take effect, so by napping during that time, you can wake up feeling more alert and refreshed. The caffeine enhances the effect of the nap, helping you feel more awake and energized when you wake up. The ideal length for a caffeine-nap is around 20-30 minutes, as longer naps may result in sleep inertia or grogginess upon waking up.
Avoid long naps
While naps can be a great thing for healthy sleepers, if you have problems falling asleep and staying asleep, then most sleep experts agree that long naps can make your sleep rhythms worse and make it harder to go to sleep that night. This is because we all have a certain amount of sleep we need each day. This is called a sleep allowance or a sleep bank. When you nap for longer than about half an hour, you are taking sleep time out of your nighttime sleep need.
As you can see in the above graph: the top chart represents healthy sleep, without a nap, and the bottom graph represents what happens to our rhythms when we take a nap. As can be seen by the change in your sleep drive (the arrows pointing down), taking a nap reduces your sleep drive, which then makes you more alert during the night time when you should be tired.
Taking a nap, especially a long one, will make it harder to fall asleep at your bedtime and/or stay asleep. It can also shift your circadian rhythm later, making it hard to fall asleep and wake up for several days in a row. Therefore, it is important to avoid long naps, if at all possible. This rule will help your body to acquire a consistent sleep rhythm so that you feel drowsy and ready to sleep at about the same time each night.
Healthy napping
People frequently take naps because they think they need to catch up on the sleep they missed or simply because they are tired and think they need a nap to get through the day. If you often feel the need to nap in the early afternoon, this is a normal part of the circadian rhythm called the “post-lunch dip.” It’s OK to take a short nap during this time, and this is a popular practice in many cultures. But problems falling asleep later on in the day can occur when your naps last for over 30 minutes. Make sure to set a smart alarm by changing the wake up time in the SleepSpace app to help you wake up from a nap, in order to ensure you keep it brief. Another option is to try to get active and get some light exposure during times you think you need to nap. The best way to do this is going for a walk outside, if at all possible. This will increase alertness and help you sleep better at night. If you can’t go outside, another option is purchase a happy lamp that emits light at 10,000 lux. Dr. Gartenberg recommends the Verilux lamp. Finally, brainwaves can be regenerative even if you don't fully fall asleep, but instead do a relaxation, such as Yoga Nidra, found within the SleepSpace app.
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Neuroscience and sleep is one of the final frontiers of human exploration.
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What are the different phases of sleep?
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REM sleep vs Non-REM Sleep. REM sleep is “almost magical” for your brain.
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In the US there are 4 stages of sleep.. but in Europe there are 5 stages of sleep… this demonstrates that our understanding of sleep is still VERY early stage.
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“N1 Sleep” - the transition between the conscious and unconscious mind.
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You want more REM and you want more DEEP SLEEP and not more light sleep.
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Deep sleep is how you prune, REM is how you integrate.
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When you are in deep sleep your brain is operating on delta waves.. which are a completely different experience to waking life.
Learn more about the science of napping in the Science of Success podcast
Some additional topics discussed include:
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When should you nap? Is napping good for you?
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Taking a power nap right at your circadian dip is often an optimal performance strategy.
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What is your circadian rhythm and how can it shape your sleep schedule and performance?
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What is “chronobiology” and how it can help us be more productive and effective?
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The importance of sunlight in controlling your circadian rhythm.
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How does intermittent fasting interact with your daily energy levels and circadian rhythms?
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What are the hacks and strategies for improving your sleep quality and getting more out of your deep sleep?
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Tip: get rid of noise pollution when you’re sleeping.
Scientific Research on the Benefits of Naps
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Naps can reduce the risk of heart disease: A study of over 23,000 Greek adults found that those who took regular naps had a 37% lower risk of dying from heart disease.
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Naps can improve physical performance: A study of professional athletes found that a 20-minute nap improved their sprint performance by 3.3%.
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Naps can improve immune function: Studies have shown that napping can improve our immune function and reduce the risk of illness. One study found that napping for 2 hours or more improved immune function by up to 40%.
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Naps can improve cognitive function: Studies have shown that naps can improve our cognitive function, including memory, attention, and creativity. One study found that a 60-minute nap improved participants' memory retention by 5 times compared to those who did not nap.
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Naps can improve mood: Napping has been shown to improve mood and reduce stress levels. Studies have found that napping can reduce levels of cortisol, a hormone associated with stress.
Can naps make up for sleep deprivation?
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• Naps cannot make up for chronic sleep deprivation: Chronic sleep deprivation, which is a consistent lack of sufficient sleep over a period of time, cannot be fully compensated for by napping. While napping can help alleviate some of the effects of sleep deprivation, such as fatigue and decreased cognitive function, it cannot fully replace the benefits of a full night's sleep.
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• Napping cannot provide all stages of sleep: A full night's sleep consists of several stages of sleep, including deep sleep and REM sleep. Napping typically only provides the lighter stages of sleep, such as stage 1 and 2, which are not as restorative as the deeper stages of sleep.
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• Naps can disrupt nighttime sleep: Napping too close to bedtime or napping for too long can disrupt nighttime sleep, leading to further sleep deprivation. Napping should be done earlier in the day and for a shorter duration to avoid interfering with nighttime sleep.
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• Naps do not address the root cause of sleep deprivation: Sleep deprivation can be caused by a variety of factors, including poor sleep hygiene, underlying health conditions, and lifestyle habits. While napping can help alleviate some of the effects of sleep deprivation, it does not address the root cause of the problem.
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• Napping cannot provide the same benefits as a full night's sleep: While napping can provide some benefits, such as increased alertness and improved cognitive function, it cannot provide the same benefits as a full night's sleep. A full night's sleep has been linked to numerous health benefits, including improved immune function, better memory consolidation, and a reduced risk of chronic health conditions.
All this being said, one reasonable strategy that would still be considered healthy sleep is to sleep for 20 minutes less than you need at night and then take a 20 minute nap during your afternoon dip. Since the last 20-minutes of sleep are light sleep anyways, when you are getting enough sleep, this will provide you with all the stages of sleep throughout the night and the charge of a nap in the afternoon. This could be considered the best of both world, and the most effective way to use naps.
Power naps, sleep inertia, and afternoon timing
A good nap should help you later today without stealing from tonight
Napping works best when you use it as a timing tool, not as a random rescue. The big questions are not only whether napping is good for you, but how long you should nap, when to nap, when to avoid it, and how to keep a nap from turning into grogginess or a worse night of sleep.
The current SleepSpace nap page already covers the essentials well: short naps are usually better than medium-length naps, early afternoon is usually better than late afternoon, and a nap becomes less helpful when it cuts into your nighttime sleep drive. What matters most is choosing the right kind of nap for the problem you are actually solving. [1] [2] [4]
A power nap is not trying to do the same job as a full sleep cycle nap. A short nap is usually about alertness, focus, and getting through the post-lunch dip. A 90-minute replacement nap is closer to sleep recovery after real sleep loss. Mixing those goals is one of the fastest ways to wake up groggy and then wonder why bedtime got harder. [2] [3] [5]
This is also why the nap conversation belongs next to circadian rhythm, schedule regularity, and the digital sleep diary. When naps keep feeling necessary, the pattern across the whole week usually tells the real story.
Choose the right nap
The first decision is not whether to nap. It is what kind of nap you are taking.
For a performance reset
Use a short power nap when the goal is alertness, not recovery sleep
A short nap of about 10 to 20 minutes is often the cleanest choice when the goal is to feel more alert without dragging sleep inertia into the rest of the afternoon. This is the sweet spot most people mean when they search for the best nap length. [1] [3]
For real sleep loss
Use a 90-minute nap when you are replacing sleep, not sneaking a quick boost
If you are genuinely sleep deprived, a longer nap that lets you move through a fuller cycle can make more sense than waking up in the middle of deep sleep. That is very different from taking a random 45-minute nap because you hit a wall. [2] [6]
The danger zone
The 30-to-80-minute range is where many naps stop feeling restorative
This is the stretch where many people wake up from deeper sleep and get hit with grogginess, confusion, and slower thinking. The problem is not that medium naps are morally wrong. The problem is that they often create the exact feeling people were trying to escape. [2] [5]
For insomnia or bedtime problems
Protect nighttime sleep drive before you optimize daytime naps
If your main problem is falling asleep at night, staying asleep, or trying to stabilize a CBT-I-style schedule, routine daytime napping often works against the plan. The short-term relief can be real, but the nighttime cost often means it does more harm than good. [1] [4]
Timing matters
Early afternoon naps usually work because they line up with biology better than late naps do
The post-lunch dip is not a character flaw. It is a predictable part of daytime alertness for many people. That is why a short early-afternoon nap can work so well if you are slightly sleep deprived. You are using a lower-alertness window instead of forcing yourself through it. [3] [4]
Late-afternoon naps are different. They may feel convenient, but they are much more likely to pull timing later, flatten sleep drive before bed, and make the whole next evening harder to read. [1] [4]
If naps are frequent enough that you need to study their timing, pair them with a digital sleep diary and morning Sleep Score review. That usually tells you faster whether the real issue is sleep debt, schedule drift, snoring, fragmented sleep, or simply a badly timed nap.
What to track around naps
- How long it took to fall asleep for the nap.
- How long the nap actually lasted, not just what you intended.
- Whether you woke up clearer, groggier, or just as tired.
- Whether the nap made bedtime later that night.
- Whether naps happen most on certain workdays, after bad nights, or during snoring-heavy weeks.
Caffeine naps and grogginess
A caffeine nap can help, but it still works best when the nap itself is brief
Why it works
A caffeine nap pairs a short doze with caffeine that is still kicking in as you wake up. The strategy can be useful for a short-term alertness problem because the nap and the caffeine attack sleepiness from different angles. [7]
What it does not fix
A caffeine nap does not solve chronic sleep debt, insomnia, or a schedule that keeps sliding later. It is a tactical move, not a full sleep plan. [4] [7]
Why some naps feel awful
Grogginess after a nap is usually not a mystery. It is often sleep inertia, which is the transition cost of waking up from deeper sleep before the brain has fully restarted high-level performance. [5]
The practical rule
If the goal is to get back to work, drive, study, or make decisions, brief usually beats medium. When the goal is genuine recovery from restricted sleep, decide that on purpose rather than drifting into it. [1] [2]
Use SleepSpace well
Use the app to control the nap, then look at the bigger pattern around it
The simplest way to make naps more useful inside SleepSpace is to use the app for three things: keep the nap brief, log what happened, and compare the nap against the rest of the week instead of judging it in isolation.
A short relaxation inside the SleepSpace app can sometimes give you enough reset without turning into a full nap at all. That can be especially helpful when you want the recovery effect of slowing down but do not want to shrink your nighttime sleep drive.
If the urge to nap keeps showing up alongside poor recovery, middle-of-the-night waking, or heavy breathing noise, it is worth checking snoring and room sound, overnight tracking, and tools based on cognitive behavioral therapy instead of treating the nap itself as the whole problem.
Related SleepSpace resources
Useful next pages if naps are part of your daytime fatigue pattern
Circadian Rhythm
Best next page if the nap question is really about the afternoon dip, late energy, or timing mismatch across the week.
Keeping a Regular Sleep Schedule
Useful when naps are starting to push bedtime later or make weekday and weekend timing feel completely different.
Digital Sleep Diary
Helpful when you want to track naps, sleep latency, awakenings, and wake time in one place instead of guessing from memory.
Benefits of Building a Sleep Drive
Important if you are working on insomnia and want to understand why routine naps can undercut nighttime sleep drive.
Track Snoring
Good next click if naps keep feeling necessary because the real issue may be fragmented sleep, breathing noise, or poor overnight recovery.
Real-Time Sleep Tracking
Useful if you want to connect daytime fatigue with what actually happened in the room and in your sleep window the night before.
Common questions
FAQ about nap length, nap timing, and waking up groggy
How long should a nap be?
If the goal is alertness and you are not majorly sleep deprived, a short nap of about 10 to 20 minutes is usually the safest place to start. If the goal is genuine recovery after sleep loss, a full-cycle nap near 75-90 minutes can make more sense. SleepSpace can help you figure out the best timing for this [1] [2]
Why do I feel worse after a nap?
The most common reason is sleep inertia. You probably woke up from deeper sleep before the brain had fully restarted alert performance. [5]
What is the best time of day to nap?
Early afternoon is usually the best fit because it lines up with the natural daytime dip in alertness better than late afternoon does. [3] [4]
Are caffeine naps actually useful?
They can be. A short nap combined with caffeine can improve alertness better than placebo and can be useful in a specific fatigue situation, but it still is not a substitute for adequate sleep. [7]
Should I nap if I have insomnia?
Usually be careful. If the main problem is falling asleep or staying asleep at night, routine naps often make the nighttime plan harder because they reduce daytime sleep drive. [1] [4]
Can naps make up for bad sleep?
They can help with alertness and performance in the short term, but they do not fully replace chronic lost sleep. A nap is a tool, not a full substitute for a stable nighttime sleep pattern. [4] [6]
Research references
Selected citations on napping, sleep inertia, power naps, and daytime alertness
Show citations (7)
- Milner CE, Cote KA. Benefits of napping in healthy adults: impact of nap length, time of day, age, and experience with napping. Journal of Sleep Research. 2009.
- Brooks A, Lack L. A Brief Afternoon Nap Following Nocturnal Sleep Restriction: Which Nap Duration is Most Recuperative?. Sleep. 2006.
- Hayashi M, Hori T. The effects of a 20-min nap before post-lunch dip. Psychiatry and Clinical Neurosciences. 1998.
- Takahashi M. The role of prescribed napping in sleep medicine. Sleep Medicine Reviews. 2003.
- Tassi P, Muzet A. Sleep inertia. Sleep Medicine Reviews. 2000.
- Bonnet MH. The Effect of Varying Prophylactic Naps on Performance, Alertness and Mood throughout a 52-Hour Continuous Operation. Sleep. 1991.
- Reyner LA, Horne JA. Suppression of sleepiness in drivers: Combination of caffeine with a short nap. Psychophysiology. 1997.