Sleep is an active, structured state in which the brain cycles repeatedly through two basic phases: non-REM sleep, which has three stages, and REM sleep. Certain stages help you feel rested and energetic the next day, while other stages help you learn information and form memories. Sleep also supports systems such as metabolism and immunity, and may help the brain clear toxins that build up during waking hours. 1 Last updated August 10, 2026 · 16 cited sources What are the stages of sleep and why do they matter? How much sleep do people actually need? What happens to your body and mind when you don't get enough sleep? How does ADHD affect sleep and what actually helps? How does autism affect sleep patterns? Which natural remedies and supplements actually help you sleep? How can couples and families sleep better together? What are the most common sleep disorders and how are they treated? If you need support now Explore the library Common questions Most read this month What other readers are opening most across this topic right now. Intrusive Sleep and ADHD: Understanding the Complex Relationship Intrusive sleep in ADHD stems from dysregulated dopamine and arousal systems. Learn why ADHD brains crash during the day and how to… Prescribed Sleep Medication List: A Comprehensive Guide to Common Sleep Aids Explore prescribed sleep medication list: 5 drug classes, safety profiles, dependence risks, and clinical evidence. Find the right sleep aid for your… Adenosine and Sleep: The Key to Understanding Your Body’s Natural Sleep Cycle Adenosine sleep research has fundamentally changed how scientists understand why you feel tired, and why you can't just think your way out… ADHD and Hypersomnia: Understanding the Complex Relationship Between Sleep Disorders and Attention Deficit Explore the intricate relationship between ADHD and hypersomnia, their symptoms, and effective management strategies for better sleep and focus. Sleep Problems in Adults with Autism: Understanding and Management Strategies Discover why 80% of autistic adults face sleep problems. Learn evidence-based management strategies, from sensory fixes to medical interventions. Sleep Debt: Understanding, Managing, and Recovering from Lost Sleep Sleep debt is the gap between the sleep your body needs and the sleep it actually gets, and it compounds. Miss an… What are the stages of sleep and why do they matter? REM stands for rapid eye movement, and each of the stages has its own pattern of brain waves and brain cell activity. You move through non-REM and REM sleep several times a night, with increasingly longer, deeper REM periods occurring later in the sleep session. The stages are not interchangeable: each is linked to different activity in the brain. 1 The third stage of non-REM sleep is where the deepest and most restorative sleep happens. Your heartbeat and breathing slow to their lowest levels and your muscles relax, and NINDS describes this as the deep sleep you need to feel refreshed in the morning. REM sleep looks very different. During most stages of sleep the thalamus, the brain's relay station for incoming signals, goes quiet, which is how you tune out the external world. In REM it becomes active again and sends the cortex the images, sounds and other sensations that fill your dreams. The amygdala, a structure involved in processing emotions, also becomes increasingly active during REM sleep. How much sleep do people actually need? Most adults need about 7 to 8 hours of good quality sleep a night, meaning a main sleep period that is long enough for them and not broken up by frequent awakenings. The recommended amount changes across the lifespan, so a child's needs are not an adult's. There is also real variation between individuals, and the amount each person needs may be partly inherited. 2 , 3 , 4 The simplest way to tell whether you are getting enough is how you feel. Waking up refreshed and not being overly sleepy during the day are good signs. If you need several cups of coffee to feel alert, that is a hint you may not be getting enough good quality sleep. If you want a more concrete estimate of your own need, a relaxing two week vacation without alarms gives you one: during the second week, note when you go to bed, when you wake and how long you slept, then average across 5 to 7 days. There is a health argument for landing in that 7 to 8 hour range too, since adults who regularly do have a lower risk of obesity and high blood pressure. What happens to your body and mind when you don't get enough sleep? Going short on sleep makes it harder to learn, focus and react. You may take longer to finish tasks, react more slowly and make more mistakes, and find it harder to make decisions, solve problems, remember things, manage your emotions and behavior, and cope with change. Day to day this shows up as feeling very tired, not waking refreshed, and struggling at work, at school, behind the wheel and with other people. 4 , 5 The effects are not only mental. Sleep deficiency raises blood sugar above normal levels, which may increase the risk of diabetes, and over time it changes how the body's defenses against germs respond, so you may have more trouble fighting off common infections. Many people count on catching up at the weekend. Extra weekend sleep does reduce how sleepy you feel, but it may not be enough in everyone to fully undo the mental effects of ongoing sleep loss, particularly the ability to sustain attention. In animals, chronic short sleep causes lasting injury to and loss of certain nerve cells, and whether that kind of damage can be reversed is not yet settled. How does ADHD affect sleep and what actually helps? Sleep problems are very common in adults with ADHD and add to the difficulties the condition already causes. Between 43% and 80% of adults with ADHD have insomnia. Stimulant and non-stimulant ADHD medications can contribute: insomnia is reported noticeably more often by people taking the medication than by people taking a placebo, though rates differ considerably between drugs. 6 , 7 Why ADHD and poor sleep travel together is not fully understood, and both genetic and individual environmental influences appear to be involved. Among the treatments that have actually been tested in adults with ADHD, the most consistent support is for morning light therapy, with early, preliminary support for melatonin, behavioral therapy and weighted blankets. Many of the sleep approaches people already use have simply not been tested in this group, so low risk options such as light therapy are a reasonable place to start. How does autism affect sleep patterns? Sleep disturbance is common in autistic children and adolescents, with somewhere between 44% and 83% having sleep problems that affect how they function during the day. The pattern usually involves trouble falling asleep and staying asleep, frequent and long awakenings during the night, irregular sleep and wake times, short overall sleep and waking very early. 8 Sleep problems are not unusual in childhood generally: up to 40% of typically developing children and teenagers have them, and these tend to ease as the child grows. The difference in autism spectrum disorder is persistence. Sleep problems often continue rather than resolving with age, which is one reason they are worth raising with a clinician rather than waiting out. Which natural remedies and supplements actually help you sleep? Melatonin is the supplement with the clearest support, but for specific problems rather than for poor sleep in general. It may help with jet lag, sleep problems caused by shift work, delayed sleep-wake phase disorder, and some sleep disorders in children. For long-standing insomnia the picture is different: melatonin may shorten the time it takes to fall asleep and reduce daytime sleepiness, but not much else, and two clinical practice guidelines have recommended against using it for chronic insomnia. 9 , 10 , 11 Herbal sleep aids have not fared well. Valerian, chamomile, kava and homeopathic sleep remedies have not been shown to work for insomnia, and kava supplements have been linked to a risk of severe liver disease. Yoga and tai chi may improve sleep quality, though not necessarily insomnia itself. Relaxation techniques used before bed, such as progressive muscle relaxation, guided imagery, biofeedback or deep breathing, are generally considered safe and can be a useful part of a wider plan to improve sleep. For most other complementary approaches, there is not enough consistent evidence to say whether they help. Natural does not automatically mean safe, so follow the label instructions and tell your health care provider what you are taking. How can couples and families sleep better together? Sharing a bed is common and it does affect how you sleep, but not in one predictable direction. When sleeping alone is compared with sleeping beside a partner, the results are mixed: sometimes both partners sleep more poorly, sometimes only the woman does, and sometimes men get more sleep. Comparisons between households point the other way, with married couples tending to sleep longer and spend less time awake after falling asleep than single people living alone. 12 , 3 , 13 The quality of the relationship seems to matter as much as the shared mattress. Both individual sleep and the way two people's sleep fits together are influenced by things like conflict between partners and overall relationship quality. Where a household can make real gains is in shared habits: everyone keeping consistent bed and wake times, a bedroom that is quiet, dark and cool, screens off at least 30 minutes before bed, no large meals or alcohol late, and no caffeine in the afternoon or evening. Daytime naps in preschool age children are normal and support healthy growth and development, so there is no need to phase them out early. What are the most common sleep disorders and how are they treated? Some people cannot get enough quality sleep no matter how hard they try, because of an underlying sleep disorder. Common ones include sleep apnea, restless legs syndrome and narcolepsy. Warning signs worth taking to a doctor are persistent trouble falling asleep, waking repeatedly through the night, and feeling sleepy or tired during the day even when you have had enough hours in bed. 3 , 14 A provider can order tests, including a sleep study, to work out whether a sleep disorder is behind the problem, and may ask you to keep a sleep diary first. For long-term insomnia, the usual first choice of treatment is not a pill but cognitive behavioral therapy for insomnia, known as CBT-I. It runs for 6 to 8 weeks and helps people fall asleep faster and stay asleep longer. It combines cognitive therapy to reduce the anxiety that builds up around not sleeping, relaxation or meditation, education about sleep habits, and sleep restriction therapy, which deliberately limits time in bed. It can be delivered by a doctor, nurse or therapist, in person, over the phone or online. Explore the library Everything we have written on this topic, grouped by what you might be looking for. The science of sleep Sleep stages, brain waves, and the mechanics behind a night's rest. Slow Wave Sleep: Understanding Deep Sleep Stages and Their Importance Drugs That Increase Slow-Wave Sleep: Enhancing Deep Sleep Naturally and Pharmaceutically Deep Sleep Stages: Understanding the Most Restorative Phase of Rest Sleep Cycle Length by Age: How Sleep Patterns Change Throughout Life Sleep Stages and Snoring: When and Why It Happens Sudden Awakenings from Deep Sleep: Causes, Effects, and Solutions REM Sleep: Understanding Its Importance, Stages, and Impact on Health Deep Sleep Wake-Up Techniques: Effective Methods to Rouse Heavy Sleepers Delta Waves Sleep: Unlocking the Power of Deep, Restorative Rest ADHD Deep Sleep: How Attention Deficit Affects Your Most Restorative Rest Trazodone and REM Sleep: Effects, Benefits, and Considerations Adenosine and Sleep: The Key to Understanding Your Body’s Natural Sleep Cycle REM Sleep Nightmares: Causes, Effects, and Coping Strategies Delta Brain Waves: Unlocking the Benefits of Deep Sleep and Healing Non-REM Sleep Disorder: Causes, Symptoms, and Treatment Options Sleep Duration for Dreaming: How Long You Need to Enter REM Sleep Sleep aids, supplements, and medications Supplements, foods, and medications people use to improve sleep, and how they compare. Best Antipsychotics for Sleep: Exploring Effective Medication Options Sedatives for Sleep: Exploring Options, Benefits, and Risks Propranolol for Sleep: A Comprehensive Look at Its Use as a Sleep Aid GHB for Sleep: Examining the Controversial Sleep Aid Doxepin for Sleep: An In-Depth Look at This Effective Sleep Aid 5-HTP and GABA Dosage for Sleep: Optimizing Your Natural Sleep Aid Regimen Gabapentin and Melatonin for Sleep: A Powerful Combination for Better Rest Dramamine for Sleep: Exploring Its Effectiveness as a Sleep Aid Flexeril for Sleep: Exploring the Use of Cyclobenzaprine as a Sleep Aid Rozerem for Sleep: A Comprehensive Guide to This Melatonin Receptor Agonist Sleep-Inducing Drugs: Exploring Instant Solutions and Ambien’s Effectiveness THC for Sleep: Benefits, Risks, and Effective Usage Mirtazapine for Sleep: Effectiveness, Dosage, and Alternatives Sleep Medication for Children: A Comprehensive Guide for Parents CBD vs THC for Sleep: Comparing Effectiveness and Side Effects Benzodiazepines for Sleep: Effectiveness, Risks, and Alternatives Sleep Medication Without Weight Gain: Effective Options for Better Rest Lorazepam for Sleep: Dosage, Effectiveness, and Considerations Melatonin for Airplane Sleep: The Ultimate Guide to In-Flight Rest Prescribed Sleep Medication List: A Comprehensive Guide to Common Sleep Aids Sleep disorders and treatment Insomnia, apnea, narcolepsy, sleepwalking, and the therapies used to treat them. Physical Therapy for Sleep Apnea: Effective Treatments to Improve Sleep Quality Sleep Paralysis Supportive Therapy: Effective Strategies for Managing Episodes NightLase Therapy: Revolutionary Treatment for Sleep Apnea and Snoring CPAP Settings for Sleep Apnea: Optimizing Your Therapy for Better Sleep Sleep Apnea CPT Codes: A Comprehensive Guide for Patients and Providers Insomnia Persists Despite Medication: Causes and Solutions Sleep Apnea and Narrow Airways: Causes, Symptoms, and Treatment Options Insomnia Support: Effective Ways to Help Someone Who Can’t Sleep ADHD and Hypersomnia: Understanding the Complex Relationship Between Sleep Disorders and Attention Deficit Sleep Paralysis and Stress: Exploring the Connection Between Mind and Body REM Sleep Behavior Disorder: Diagnosis, Treatment, and Management Strategies Insomnia Solutions: What to Do When You Lay in Bed for Hours Unable to Sleep Can’t Sleep? 15 Effective Strategies to Beat Insomnia and Get Better Rest Nocturnal Hypoxemia Without Sleep Apnea: Causes, Symptoms, and Treatment Options Central Sleep Apnea: Neurological Causes and Implications Daytime Sleep vs. Nighttime Insomnia: Causes and Solutions Insomnia After Hysterectomy: Causes, Effects, and Solutions Anxiety-Induced Insomnia: Effective Strategies for Restful Sleep How attention differences affect bedtime, sleep quality, and daytime energy. ADHD Medication and Insomnia: Understanding the Connection and Finding Solutions ADHD and Sleep: Understanding the Connection Between Boredom, Falling Asleep, and Alarm Struggles Cricketing Feet: The Surprising Link Between ADHD, Sleep, and Leg Movement ADHD Sleep Medication List: Effective Options for Better Rest ADHD Child Sleep Solutions: Proven Strategies to Help Your Child Rest Better ADHD Staying Up Late: Why Sleep Revenge Affects Adults and How to Break the Cycle Sleeping After Adderall: Strategies for Better Rest While on ADHD Medication Bedtime Routine for ADHD Child: Creating Calm Evenings and Better Sleep

ADHD and Early Waking: Understanding and Managing Your Child’s Sleep Patterns Intrusive Sleep and ADHD: Understanding the Complex Relationship The Ultimate Bedtime Routine for ADHD Adults: Strategies for Better Sleep and Improved Focus Sleep All Day, Up All Night: Causes, Consequences, and Solutions for Disrupted Sleep Patterns The Complex Relationship Between Depression and Sleep: Understanding Excessive Sleep and Its Impact on Mental Health Sleep Inertia and ADHD: Understanding the Struggle and Finding Solutions Sleep Problems in Children: Causes, Solutions, and When to Seek Help Dopamine and Sleep: The Intricate Dance of Neurotransmitters in Rest Autism and sleep Sensory patterns, sleep positions, and strategies specific to autistic sleepers. Autistic Insomnia: Why Sleep Eludes Many on the Autism Spectrum Autism and Night Terrors: Connection and Solutions for Better Sleep Autism Bedtime Routine: A Comprehensive Guide for Parents Autism and Co-Sleeping: Benefits and Challenges for Families Autism and Sleeping Too Much: The Connection Between Autism and Hypersomnia Sleep Problems in Adults with Autism: Understanding and Management Strategies Autism Sleep Aids: Effective Solutions for Better Rest Autistic Sleeping Positions: Insights and Solutions for Better Rest Autistic Children’s Sleep Regression: Causes and Management Strategies Autism Sleep Behaviors: Hand Posturing and Unusual Nighttime Movements Autism and Floor-Related Behaviors: Why Individuals May Lie or Sleep on the Floor Sleep Apnea and Autism: The Complex Relationship, Diagnosis, and Management Sleep deprivation and sleep debt The effects, timeline, and recovery process of running on too little sleep. Sleep Deprivation by Hour: A Timeline of Mental and Physical Effects Sleep Deprivation Recovery: Healing Your Body and Mind After Years of Poor Sleep Sleep Abuse: The Hidden Epidemic of Chronic Sleep Deprivation Sleep Recovery After an All-Nighter: How Long Should You Rest? Working Out on No Sleep: Risks, Benefits, and Strategies for Exercise When Exhausted Sleep Debt: Understanding, Managing, and Recovering from Lost Sleep Staying Awake After No Sleep: Effective Strategies for Alertness All-Nighter vs. Sleep: Making the Right Choice for Your Productivity and Health Long-Term Sleep Deprivation Face: How Chronic Lack of Rest Affects Your Appearance Manic Episodes and Sleep Deprivation: Exploring the Limits of Wakefulness Leg Aches and Sleep Deprivation: The Surprising Connection No Sleep Survival Guide: Navigating Your Day After a Sleepless Night Sleep-Deprived Face: How to Look Refreshed Even After No Sleep Eye Pain from Sleep Deprivation: Effective Remedies and Prevention Strategies Sleep and relationships Cuddling, co-sleeping, arguments at bedtime, and sleeping apart. Cuddling and Sleep: The Intimate Connection of Resting in Your Partner’s Arms Cuddling and Sleep: The Science Behind This Cozy Connection Co-Sleeping’s Psychological Benefits: Nurturing Child Development and Family Bonds Sleep Dependency: Navigating Nights Without Your Partner Sleeping When Angry: Effective Techniques for Calming Your Mind at Night Co-Sleeping and Child Dependency: Examining the Long-Term Effects Grief and Sleep: Navigating Rest During Times of Loss Partner Sleeping While You’re Upset: Navigating Emotional Disconnect in Relationships Sleep Disturbances with a Partner: Causes and Solutions for Better Rest 15 Effective Techniques to Destress Before Bed for a Peaceful Night’s Sleep Sleep Cuddling: The Subconscious Expression of Affection and Intimacy Sleeping Next to Someone You Love: Effects on Sleep Quality and Well-being The psychology of sleep Sleeping positions, personality links, and what psychology says about our nightly habits. Psychology of Bed Sides: What Your Sleeping Position Reveals About You The Best Sleeping Position for Anxiety: A Comprehensive Guide to Better Rest Bedroom Color Psychology: How Your Choices Affect Mood and Sleep Sleeping on the Floor Psychology: Exploring the Mental and Physical Effects BPD and Sleep: Navigating the Complex Relationship Between Borderline Personality Disorder and Rest Sleep’s Restorative Theory: Exploring the Psychology Behind Repair and Restoration Psychology of Sleeping with Door Open: Exploring Habits, Fears, and Benefits Sleeping with Multiple Pillows: The Psychology Behind Pillow Hoarding Fetal Position Sleeping: Psychological Insights and Hand Placement Significance Ancient Sleep Deities: Exploring Divine Guardians of Slumber Across Cultures Sleep Position Change: A Step-by-Step Guide for Better Rest Sleeping Diagonally: Causes, Implications, and Solutions for This Unusual Sleep Position Ancient Human Sleep Patterns: Unveiling Prehistoric Slumber Habits Glymphatic System Sleep Position: Optimizing Brain Health Through Proper Rest Everything else in this library that is not featured in a collection above. Side Sleeping Without Shoulder Pain: Expert Tips and Techniques Shirtless Sleep: Why Men Often Prefer Sleeping Without a Top Hot Feet at Night: Causes, Remedies, and How to Get Better Sleep Sleeping with Feet Elevated: Benefits, Risks, and Best Practices Sleeping with Legs Elevated: Benefits, Risks, and Best Practices Left Side Sleeping Pain: Causes, Solutions, and When to Seek Help Sleeping with Head Elevated: Benefits, Risks, and Best Practices Ear Infection Sleep Guide: Best Positions and Pain Management Techniques Catheter Sleep Solutions: Comfort and Rest with a Urinary Catheter Sleeping After a Cortisone Shot: Effective Strategies for Comfort and Recovery Sour-Smelling Night Sweat: Causes and Solutions for Unpleasant Sleep Odors Left-Side Sleeping: Benefits, Risks, and Comparison with Right-Side Sleeping Sleep Positions for Nausea Relief: Finding Comfort During Stomach Discomfort Rib Pain When Sleeping on Your Side: Causes, Prevention, and Solutions Common questions Is it bad to nap during the day? Napping can boost alertness and performance, and for adults the advice is to keep it to no more than 20 minutes. If you have trouble falling asleep at night, limit naps or take them earlier in the afternoon. In preschool age children, napping is normal and supports healthy growth. 13 What is sleep debt and can you actually catch up on it? Catching up at the weekend does make you feel less sleepy, but feeling better is not the same as being recovered. One weekend of recovery sleep may not be enough in everyone to fully reverse the mental effects of ongoing sleep loss, especially the ability to stay vigilant. 5 Why do I wake up tired even after a full night's sleep? Quality matters as much as quantity, and feeling tired despite enough hours is itself a sign of poor sleep quality, alongside trouble falling asleep and waking repeatedly in the night. If it persists, a provider can look for an underlying sleep disorder, sometimes using a sleep diary or a sleep study. 3 Is it safe to take melatonin every night? Melatonin has a role in specific problems such as jet lag, shift work and delayed sleep-wake phase disorder, but two clinical practice guidelines have advised against using it for chronic insomnia, so nightly long-term use is not the intended purpose. Natural does not always mean safe: follow the label and tell your health care provider you are taking it. 9 , 10 What causes sleep paralysis? Sleep paralysis is a brief period, either as you fall asleep or as you wake, when you cannot move voluntarily even though your eyes and breathing keep working and your mind is clear. Episodes are most likely when sleeping on your back, and around 7.6% of people in the general population have had at least one, with higher rates among students and among people with psychiatric conditions such as panic disorder. 16 Why do some people seem to need less sleep than others? How much sleep a person needs varies, and it may be an inherited trait. Gene mutations have been identified in some people who naturally sleep 6 hours or less, appear healthy, function well and show less decline in performance when they are kept short of sleep. 2 Is it normal to remember dreams every night? Most dreaming occurs during REM sleep, although some dreaming can also occur in non-REM sleep. In REM the thalamus becomes active again and sends the brain's outer layer the images, sounds and other sensations that fill dreams. REM periods grow increasingly longer and deeper later in the sleep session. 1 Why do I sleep more when I'm stressed or grieving? Sleep and emotion are linked: the amygdala, a structure involved in processing emotions, becomes increasingly active during REM sleep. And when sleep is short, managing emotions and behavior and coping with change get harder, which can make a difficult period feel heavier. If your sleep changes markedly and stays that way, a sleep diary and a conversation with a provider are a sensible next step. 1 , 4 , 3 Every claim on this page is linked to a source we have checked. If you spot something out of date, please tell us. 1. Brain Basics: Understanding Sleep National Institute of Neurological Disorders and Stroke 2. Module 2: How Much Sleep Do You Need? (NIOSH Work Hour Training for Nurses) National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention 3. About Sleep Centers for Disease Control and Prevention (2025) 4. Sleep Deprivation and Deficiency: How Sleep Affects Your Health National Heart, Lung, and Blood Institute 5. Neural Consequences of Chronic Short Sleep: Reversible or Lasting? Frontiers in Neurology (via PubMed Central) 6. Adult Attention-Deficit/Hyperactivity Disorder (ADHD) and Insomnia: an Update of the Literature Current Psychiatry Reports (indexed in PubMed) (2017) 7. Managing Sleep in Adults with ADHD: From Science to Pragmatic Approaches Brain Sciences (indexed in PubMed) (2021) 8. Practice Guideline: Treatment for Insomnia and Disrupted Sleep Behavior in Children and Adolescents With Autism Spectrum Disorder American Academy of Neurology (published in Neurology) (2020) 9. Sleep Disorders and Complementary Health Approaches: Usefulness and Safety National Center for Complementary and Integrative Health 10. Melatonin: What You Need To Know National Center for Complementary and Integrative Health 11. Myth-Busting Popular Natural Products Marketed for Disease Prevention and Wellness: What the Science Says National Center for Complementary and Integrative Health 12. Bed-Sharing in Couples Is Associated With Increased and Stabilized REM Sleep and Sleep-Stage Synchronization Frontiers in Psychiatry (via PubMed Central) (2020) 13. Sleep Deprivation and Deficiency: Healthy Sleep Habits National Heart, Lung, and Blood Institute 14. Insomnia: Treatment National Heart, Lung, and Blood Institute 15. 988 Suicide & Crisis Lifeline Substance Abuse and Mental Health Services Administration 16. Lifetime Prevalence Rates of Sleep Paralysis: A Systematic Review Sleep Medicine Reviews (via PubMed Central)