Sleep 101

Introduction

Sleep is the body's nightly tune-up. Your brain and body need sleep to clean out waste, repair tissues, regulate hormones, and reset your memory and emotional balance. This seemingly simple act of closing the eyes and drifting off has been found in research to impact nearly every aspect of our health, from cellular repair to psychological well-being1.

In the bigger picture, sleep can affect how well your body can defend itself, how you think, and how you feel. It plays a vital role in brain function, mental health, immune defense, metabolism, and cardiovascular health2,3.

Essentially, sleep isn’t just about feeling rested; it’s one of the body’s most powerful tools for healing and health.

What happens during sleep?

Sleep is a natural, recurring state in which muscles relax and the body cycles through different stages that help restore and balance internal systems. During this time, a series of complex biological processes take place4.

When we fall asleep, the body shifts into an active, carefully orchestrated cycle of healing and rebalancing. Sleep happens in two main categories: NREM (non-rapid eye movement) sleep and REM (rapid eye movement) sleep. These two types cycle throughout the night in 90-minute intervals, like waves washing over the brain and body, each with its own purpose4.

During NREM sleep, especially in the deep stages known as slow-wave sleep, your body slows down—heart rate drops, muscles relax, and brain activity quiets. This is when physical restoration occurs. Cells repair themselves, the immune system regenerates, and growth hormone is released to support tissue healing. Your brain also uses this time to flush out waste products that may accumulate during periods of wakefulness5,6.

Then comes REM sleep, when your brain becomes active again—almost as active as when you're awake. This is the dreaming phase, when emotional processing occurs7. The brain sorts through the day’s information, reinforces learning, and strengthens neural connections. It’s like overnight maintenance of thoughts and emotions8.

Behind all of this is a highly tuned system of brain chemistry and signals. Specific areas of the brain coordinate sleep by releasing neurotransmitters that slow down brain activity and guide you into sleep stages4. These chemical messengers are influenced by your circadian rhythm, an internal clock that’s largely driven by light and dark9. In short, sleep is the body’s nightly maintenance program—and when you shortchange it, your health can pay the price.

Why is sleep important?

• Immune function: Sleep promotes healthy immune activity by helping to increase the production of proteins that fight infection and reduce inflammation, while also supporting immune cell function10.
• Brain health and memory: During sleep, especially in REM and deep stages, the brain consolidates memories, processes information, and removes waste products that accumulate during waking hours11.
• Mental health: Consistent, restorative sleep helps regulate mood and emotional processing by helping balance neurotransmitters and reduce the stress hormone cortisol, potentially reducing risk for depression and anxiety12.
• Cardiovascular health: Sufficient sleep supports heart function by helping to stabilize blood pressure, reduce sympathetic nervous system activity, and modulate inflammation in blood vessels—factors known to influence heart disease risk13.
• Weight and appetite control: Sleep loss is associated with increased levels of ghrelin (hunger hormone) and reduced leptin (satiety hormone), potentially contributing to higher food intake and weight gain14.
• Metabolic health: Poor sleep can impair insulin sensitivity and glucose metabolism, potentially elevating the risk of type 2 diabetes and metabolic syndrome15,16.
• Longevity and general health: Higher sleep quality and regular duration are consistently linked with better physical health, emotional resilience, and life expectancy17.

Fundamentals of sleep

Sleep is a highly organized process that follows a repeating pattern throughout the night, known as sleep architecture, which refers to how the body cycles through different stages of sleep in a predictable order. Each cycle includes NREM stages and REM sleep4, each lasting about 90 minutes and repeating several times a night, like waves gently lapping the shore.

Healthy sleep architecture is key because it ensures the body moves through all the necessary stages to support healing, brain function, and emotional regulation1. Disruptions in this architecture—such as waking often or skipping REM sleep—can reduce the quality of sleep even if total hours in bed seem adequate18.

The role of your body’s internal clock–the circadian rhythm

A key part of what regulates this sleep pattern is the circadian rhythm. The circadian rhythm is your body’s internal clock that operates on roughly a 24-hour cycle. It tells your body when to feel alert and when to feel sleepy, based on environmental cues—especially light and darkness19. When this rhythm is aligned properly, it helps your brain signal the release of melatonin (a natural sleep hormone), control body temperature, and keep sleep stages in balance throughout the night9. The release of melatonin increases in the evening when it's dark, signaling the body that it’s time to wind down and prepare for sleep20. Because of its strong connection to this biological clock, melatonin is called a chronobiotic, as it can shift or reset the timing of the circadian rhythm21.

That’s one of the primary reasons why consistent sleep and wake times are so important—not just for falling asleep, but for getting high-quality sleep that supports overall health.

Sleep stages

NREM sleep stages

Non-rapid eye movement (NREM) sleep is divided into three stages: N1, N2, and N3.

• N1 (light sleep): This is the transition from wakefulness to sleep. It's a light sleep stage that usually lasts just a few minutes. During N1, the brain starts to slow down, muscle activity decreases, and people may experience a sensation of falling or brief muscle twitches called hypnic jerks4. It’s easy to be awakened in this stage, and it accounts for only about 5% of total sleep22.
• N2 (deeper light sleep): This is where the body begins to truly disconnect from the outside world. Brain waves continue to slow, but short bursts of activity called sleep spindles and K-complexes occur, which may help with memory consolidation and sensory processing23,24. Heart rate and body temperature begin to drop, and this stage makes up about 45%-55% of total sleep in healthy adults4.
• N3 (deep sleep or slow-wave sleep): This is the most restorative and hardest stage to wake from. Brain waves during this phase are very slow (called delta waves), and the body shifts into repair mode, releasing growth hormone, strengthening the immune system, and repairing tissues25. Deep sleep is especially important for physical recovery and feeling refreshed the next day, and it tends to occur more in the first half of the night22.

REM sleep

Rapid eye movement (REM) sleep is the most active and mysterious stage of sleep, where the brain lights up with activity while the body stays mostly still. This is the phase where most dreaming happens, and while the eyes dart rapidly under closed lids, the muscles of the body are temporarily paralyzed26. REM sleep is essential for emotional health, memory consolidation, and learning; during this time, the brain sorts through information from the day, deciding what to keep and what to discard4. It also supports neural plasticity, the brain’s ability to adapt and form new connections—especially important for development and long-term brain health27. REM cycles tend to grow longer as the night goes on, making the final hours of sleep especially important for mental restoration.

Sleep cycles

Sleep moves through a series of cycles every night. These cycles alternate between NREM and REM sleep. A typical night consists of 4-6 of these cycles, beginning with deeper, more restorative NREM stages and transitioning into longer periods of REM sleep as the night progresses4. These cycles are influenced by individual factors like age and sleep duration. This natural rhythm allows the body to focus on physical repair early in the night and shift toward mental and emotional restoration closer to morning28. Understanding the structure and timing of these cycles is important because disruptions—like frequent waking or shortened sleep duration—can prevent the body from reaching these critical stages, even if total sleep time seems adequate.

Understanding how sleep cycles work can help you plan your sleep and, potentially naps, in a way that supports better rest. For example, the idea of a "power nap" comes from this concept. A power nap is a short nap, usually 10-20 minutes, that helps recharge the brain without letting you fall into deep sleep. This brief rest can boost alertness and performance while avoiding grogginess29. Staying in lighter sleep stages like stage 1 or 2 may keep you clear-headed and better aligned with the natural sleep cycle. Naps over 30 minutes risk dipping into deeper stages, which may leave you feeling groggy instead of restored30.

The composition of sleep cycles evolves over the course of the night4:

• Early cycles (first half of the night): These cycles are rich in NREM stage N3, or deep sleep. This is when the body focuses on physical repair—healing tissues, building bone and muscle, and boosting immune function. Growth hormone is released to support tissue healing, and the brain flushes out metabolic waste.
• Later cycles (second half of the night): These cycles contain more REM sleep. The brain becomes highly active, processing emotions, consolidating memories, and making sense of new information. REM periods also grow longer with each cycle, which is why the early morning hours are especially important for brain function.

The glymphatic system

You’ve probably heard about the lymphatic system—your body’s natural drainage system that helps remove waste and toxins. The brain has its own version of it called the glymphatic system. The name is derived from the involvement of specialized brain cells, called glial cells. In short, it’s a glial-driven lymphatic-like system—hence the name glymphatic31,32.

The glymphatic system is the brain’s waste clearance system, and it works best while you sleep. Think of it like an overnight cleaning crew. Cerebrospinal fluid (CSF), a clear fluid that surrounds and protects your brain and spinal cord, flows through channels along the blood vessels in your brain. This CSF washes through the brain’s tissue, picking up waste products—like discarded proteins and toxins—and carries them away33.

Furthermore, during deep sleep, brain cells can shrink slightly, allowing the space between cells to expand, making more room for CSF to flush out unwanted waste34. This cleaning process is especially important in helping to maintain optimal cognitive functioning during aging35.

When sleep is disrupted or poor in quality, this clearance system doesn’t work as well, and waste can accumulate over time, potentially impacting memory, mood, and overall brain health36. Keeping the glymphatic system healthy starts with consistent, deep, and restorative sleep—something that matters not just for rest but for long-term brain protection.

Chronotypes

Chronotypes refer to an individual's natural inclination towards specific sleep-wake patterns, the body’s built-in preference for when to sleep and wake up37. Chronotypes are guided by circadian rhythm. While circadian rhythm is a universal biological process that we all have, your chronotype is more like a personal schedule that determines how your body syncs up with that clock38.

These preferences influence when a person tends to feel most alert and when they are more likely to feel tired. “Morning people” and “night owls”—that’s chronotype in action. This rhythm isn’t just about sleep; it affects mood, metabolism, hormones, and even how well the brain functions throughout the day37.

Interestingly, chronotypes are not as fixed as once believed. They can shift over time due to various factors, including age, lifestyle changes, and even alterations in gut microbiome composition39,40. Understanding your chronotype may help you make better decisions about your sleep habits, work schedule, and even meal timing to stay in sync with your natural rhythm to maintain good health41.

Root cause approach to sleep

A root cause approach to sleep starts with the idea that sleep disturbances are not isolated problems. Instead of just prescribing a sleep aid to “knock you out,” a root cause approach digs into the underlying imbalances that might be disrupting the body’s natural sleep rhythms. These root causes can include blood sugar imbalances, chronic stress, nutrient deficiencies, inflammation, hormonal shifts, and even gut microbiome disturbances42. A comprehensive approach treats sleep less like a one-size-fits-all diagnosis and more like a window into deeper biological dysfunction.

It might also include testing for biomarker patterns, optimizing diet to balance blood sugar, supporting relaxation through mind-body therapies, or correcting nutrient deficiencies—all targeted to restore the body’s natural capacity to fall and stay asleep, bringing the system back into harmony. Rather than forcing sleep to happen, this approach aims to remove the barriers preventing it.

Factors affecting sleep quality

Sleep quality can be shaped by a range of physical, mental, behavioral, and environmental factors. While some of these are within our control—like lifestyle choices—others, such as age or medical conditions, may require deeper investigation and targeted support. Here are several factors known to impact how well the body falls, stays, and cycles through sleep:

• Stress and mental health: High stress levels, anxiety, and depression can make it hard to fall or stay asleep. These conditions keep the brain in a more alert state, which can delay sleep onset, cause frequent nighttime awakenings, and prevent entry into deep, restorative sleep43,44. For more information on stress management and mental health, visit Mental Health 101 and Stress Management 101.
• Irregular sleep schedule: Going to bed and waking up at inconsistent times disrupts the circadian rhythm. Irregular patterns can lead to lighter, fragmented sleep and increased risk of insomnia or daytime drowsiness45,46. People with inconsistent sleep schedules have been shown to experience more metabolic issues, more overall inflammatory imbalance, and higher risks of obesity and cardiovascular disease—even if their total sleep time is adequate47,48.
• Sleep environment: A bedroom that is too bright, noisy, warm, or uncomfortable can keep the body in a state of light, disturbed sleep, interfering with the body’s ability to enter and maintain deeper stages49,50. An ideal environment is cool, quiet, and dark, with minimal interruptions throughout the night51,52.
• Underlying health conditions: Medical issues like chronic pain, acid reflux, and autoimmune diseases can contribute to poor sleep53,54. People with these conditions often experience fragmented sleep, which in turn can worsen pain perception55.
• Age-related changes: Older adults often experience changes in sleep architecture56,57, spending less time in deep sleep, waking more frequently during the night, and experiencing early wake times, which can lead to lighter, more fragmented rest58.

Impact of technology on sleep

Technology has become a central part of modern life, but it can come at a cost to our sleep. From late-night screen time to the constant buzz of notifications, digital habits can disrupt the body’s natural rhythm and make it harder to fall asleep, stay asleep, or get restful sleep. That’s because our sleep cycle is tightly regulated by light exposure and brain activity. Here are some key ways technology may interfere with healthy sleep:

• Blue light exposure: Devices like phones, tablets, and laptops emit blue light, which suppresses melatonin, shifting the body’s internal clock. This makes it harder to fall asleep and can push the body's sleep schedule later into the night59,60.
• Use of screens at bedtime: Using devices right before bed can delay sleep onset, reduce total sleep time, increase nighttime awakenings, and lead to feeling groggy and unfocused the next day61,62.
• Increased mental health strain: High screen time—especially on social media—has been linked with increased anxiety and depression. Sleep disturbances often go hand in hand with these outcomes, creating a feedback loop of poor rest and emotional stress63.

Diet and sleep

What we eat affects more than just our nutritional status or energy; it also impacts how well we sleep. Food choices can influence the hormones and brain chemicals that control when we fall asleep and how deeply we rest. And it works both ways: diet affects sleep, and sleep can affect how we eat64,65.

Macronutrients and sleep

Each of the macronutrients—carbohydrates, protein, and fats—interacts with the brain and hormones in unique ways that can either help or hinder restful sleep. Here's how each of them may play a role:

• Carbohydrates: Diets high in refined carbs and added sugars are linked with lighter, more restless sleep66. These foods can cause blood sugar spikes and crashes that interfere with the brain's ability to stay in deep, restorative sleep stages67. Replacing high-sugar, processed foods with whole, fiber-rich carbs—like fruits, vegetables, and whole grains—may help improve sleep quality68.
• Proteins: Moderate protein intake, especially from sources rich in tryptophan (like turkey, eggs, nuts, or seeds), may help with falling asleep and staying asleep by supporting serotonin production69.
• Fats: The type of fat consumed can affect sleep68. Diets high in saturated fats have been linked to lighter, more disrupted sleep, while moderate amounts of healthy fats (like omega-3s from fish or flaxseeds) may support deeper sleep stages and better sleep efficiency69,70.

For more information on foundational nutritional principles and eating practices that promote health, visit Nutrition 101.

Micronutrients and sleep

Certain vitamins and minerals play a surprising yet powerful role in how well we sleep. They support the brain’s chemical messengers, help regulate hormones, and even influence muscle relaxation.

• Magnesium: Magnesium helps the body relax by helping to calm the nervous system and supporting healthy melatonin levels. Low magnesium levels have been linked to insomnia, frequent night waking, and poor sleep efficiency71,72.
• Vitamin D: This prohormone helps support immune function and whole body health. Preclinical evidence shows that it may also play a role in regulating the body’s internal clock and supporting sleep depth73. Deficiencies have been linked to shorter sleep duration and an increased risk of sleep disorders69,74.
• B vitamins (especially B6): These vitamins are involved in producing serotonin and melatonin—two molecules that help regulate mood and sleep. Low levels, particularly of B6, have been associated with insomnia and restless sleep75.
• Zinc: This mineral supports brain signaling and melatonin regulation. Low zinc levels have been linked to poor sleep duration and quality, especially in older adults76,77.
• Omega-3 fatty acids: These healthy fats, found in fatty fish like salmon or in flaxseeds, support brain health and help reduce inflammation. Supplementation with omega-3 fatty acids has been shown to help improve sleep efficiency, reduce night wakings, and support mood—all of which can benefit sleep quality78,79.

Meal timing

When you eat can impact your sleep just as much as what you eat. Eating late—especially within two hours of bedtime—can cause indigestion and disrupt sleep since your body’s digestion slows down at night. Consuming most of your calories late in the evening may also upset gut bacteria and trigger inflammation, interfering with your natural sleep-wake cycle. In contrast, time-restricted eating (like eating between 8 a.m. and 6 p.m.) may improve sleep quality by allowing digestion to finish before bedtime and helping your body stay in sync with its internal clock80.

Caffeine and alcohol

These widely consumed substances have been shown to impact sleep in various ways:

• Caffeine: Caffeine stimulates the nervous system and can delay sleep onset, reduce deep sleep and total sleep time, even when consumed 6-8 hours before bedtime69,81.
• Alcohol: While alcohol may help with falling asleep, it can disrupt sleep architecture, particularly REM sleep, leading to poor sleep quality82,83.

Sleep disorders

Sleep disorders are conditions that interfere with the ability to fall asleep, stay asleep, or feel refreshed after sleep. They’re surprisingly common and can affect everything from energy and mood to immune function and long-term health84. While occasional poor sleep is normal, chronic disruptions can signal a deeper problem with how the body regulates sleep. This often traces back to issues with the circadian rhythm37 and can arise from stress, medical issues, environmental factors, or lifestyle choices85.

Sleep architecture challenges

When this natural rhythm is disrupted, sleep becomes less restorative and more fragmented. Over time, these disruptions can take many forms, each affecting the body and mind in different ways:

• Sleep inertia: This refers to the grogginess and confusion some people feel immediately after waking, especially when abruptly woken from deep sleep. It can impair focus, coordination, and decision-making for up to 30 minutes or more86.
• Fragmented sleep: Frequent awakenings during the night—even briefly—can break sleep into disconnected chunks. Even if total sleep time seems adequate, the body doesn’t get enough uninterrupted time in deep or REM stages87.
• REM rebound: When REM sleep is regularly suppressed—such as from stress, alcohol, or certain medications—the body may attempt to “catch up” with intense REM activity in subsequent nights. This can lead to vivid dreams, night sweats, and disrupted sleep88,89.

Here's a closer look at some of the more common types of sleep disorders managed in a clinical setting:

Insomnia

This is the most frequently reported sleep disorder. About 10% of adults have an insomnia disorder, while another 20% experience insomnia symptoms90. It involves trouble falling asleep, staying asleep, or waking too early and not being able to return to sleep. It can be short-term, often due to stress or life changes, or chronic, lasting at least three nights per week for three months or longer. Insomnia is associated with poor concentration, mood issues, weakened immune response, and an increased risk of chronic disease89.

Sleep apnea

A disorder where breathing repeatedly stops and starts during sleep. The most common type is obstructive sleep apnea (OSA), caused by airway blockage and is estimated to affect 9%-38% of adults, with prevalence increasing with age and obesity91. Another form, central sleep apnea, results from the brain failing to send proper signals to breathing muscles, and complex sleep apnea includes elements of both. Symptoms may include loud snoring, gasping during sleep, and daytime sleepiness. Untreated sleep apnea increases the risk of high blood pressure, heart disease, stroke, and type 2 diabetes92.

Restless leg syndrome (RLS)

A condition involving uncomfortable sensations in the legs, often described as crawling or tingling, paired with a strong urge to move them—especially in the evening or at night. RLS affects approximately 7%-10% of adults, with higher rates among women and older adults93. Movement provides temporary relief, but this sleep disruption can lead to chronic fatigue and mood disturbances. RLS is sometimes related to iron deficiency, pregnancy, or chronic conditions. Over time, it can contribute to chronic sleep loss and cardiovascular disease94.

Narcolepsy

A neurological condition that disrupts the regulation of sleep and wake cycles. Narcolepsy affects about 1 in every 2,000 people in the U.S., though it is often underdiagnosed95. It often involves excessive daytime sleepiness and sudden “sleep attacks,” which are sudden, uncontrollable periods of intense drowsiness and inability to stay awake. Some individuals also experience cataplexy, a sudden loss of muscle tone triggered by emotions, as well as sleep paralysis and vivid dreams96. Narcolepsy can impair safety and daily functioning if left untreated97.

Parasomnias

These are unusual behaviors or experiences that occur during sleep, such as sleepwalking, night terrors, talking during sleep, or acting out dreams (called REM sleep behavior disorder). These events may be harmless or, in some cases, pose safety risks to the person or others. Parasomnias can be triggered by stress, medications, or sleep deprivation and are more common in children but can affect adults as well98.

Circadian rhythm sleep-wake disorders

These disorders result from a mismatch between the internal body clock and the external environment. Common types include delayed sleep phase disorder (falling asleep and waking up too late), advanced sleep phase disorder (falling asleep and waking very early), jet lag, and shift work disorder. Symptoms can include insomnia, daytime sleepiness, and reduced performance. Long-term circadian misalignment is linked to metabolic dysfunction, mood, and certain neurodegenerative disorders99,100.

Emerging sleep issues

Sleep science continues to evolve, and as researchers learn more about how modern life affects rest, several emerging sleep disorders have come into focus. These newer or newly recognized conditions reflect how stress, trauma, environmental disruption, and technology can influence sleep in unexpected ways.

Revenge bedtime procrastination

This describes the habit of staying up late to reclaim personal time after a busy or stressful day, even when exhausted101. The name comes from the idea that people are “taking revenge” on daytime obligations by delaying sleep, which can lead to chronic sleep deprivation and increased fatigue, poor mood, and brain fog102.

Long COVID-associated sleep disturbances

Many people recovering from COVID-19 report ongoing sleep issues such as insomnia, fragmented sleep, and excessive daytime sleepiness. These disruptions may result from lingering inflammation, stress, or autonomic nervous system dysregulation. Sleep problems can persist for months and worsen other symptoms like brain fog and anxiety103,104.

Gaming-related sleep issues

With the rise of online gaming and e-sports, a new category of sleep disturbances related to excessive gaming has emerged. Late-night gaming—especially involving competitive or high-stimulation games—can delay sleep onset, suppress melatonin production due to screen exposure, and fragment sleep throughout the night105. This is especially common among teens and young adults. Chronic gaming-related sleep loss can impair memory, mood regulation, and metabolic health106.

Social jet lag

This happens when weekend sleep schedules drift significantly later than weekday patterns, especially due to late-night screen use or social activities. The internal clock becomes misaligned with the environment, similar to travel-related jet lag107. It can be like experiencing mild jet lag every Monday. Over time, this mismatch is linked to metabolic disorders and mood disturbances108.

Tips for improving sleep hygiene

Sleep hygiene refers to the daily habits and environmental choices that support healthy, restful sleep. Just like dental hygiene helps keep teeth clean and strong, sleep hygiene keeps the brain and body aligned for better rest. Practicing good sleep hygiene can help regulate the body’s internal clock and sets the stage for falling asleep faster, staying asleep longer, and waking up more refreshed109,110.

Here are some evidence-based tips for building strong sleep hygiene habits:

Stick to a consistent sleep schedule, even on weekends

• Going to bed and waking up at the same time every day (sleep consistency) helps train the brain and body to expect sleep at a regular time111. Sleep consistency is one of the most important—but often overlooked—predictors of sleep quality, influencing mental clarity, hormonal balance, and long-term health12,112.

Create a comfortable sleep environment

• A dark, cool, and quiet bedroom promotes better sleep. This comfortable environment helps support deep, uninterrupted sleep. Fine-tuning your bedroom temperature can better suit your preferences, but research suggests that cooler environments are more conducive to sleep (around 62-77 ℉)113,114.

Exercise regularly

• Regular physical activity can improve sleep quality. However, vigorous exercise close to bedtime may have the opposite effect for some individuals (try to finish intense workouts at least 2 hours before bed)69,115.

Establish a relaxing bedtime routine

• Gentle activities like reading, stretching, or listening to soft music (a 30-minute relaxation period) can signal the body that it’s time to wind down116,117.

Reconsider daytime naps

• While short naps can be refreshing, long or late-afternoon naps may interfere with nighttime sleep. If you nap during the day, try to limit it to 30 minutes to avoid the grogginess associated with sleep inertia29,118.

Limit screen time 1-2 hours before bed

• Blue light from phones, tablets, and TVs can delay melatonin production and interfere with sleep onset59,119.

Avoid caffeine after mid-afternoon and in the evening

• Caffeine is a stimulant that can stay in your system for hours, delaying sleep and reducing sleep quality, especially in sensitive individuals. Even if you drink caffeine 6 to 8 hours before bedtime, its effects can still linger in your system69,81.

Reserve the bed for sleep and intimacy only

• Associating the bed with relaxing activities—rather than work or screen time—can help the brain link the bed with sleep rather than work or entertainment120.

Non-drug therapies to support sleep

Getting good sleep doesn’t always mean reaching for a prescription. In fact, many people find real, lasting relief through natural and evidence-based therapies that work with the body’s own rhythms. These approaches aim to calm the nervous system, reset the sleep-wake cycle, and improve sleep quality. Whether used alone or alongside other treatments, they can be powerful tools in a root-cause approach to sleep health.

Here are some of the most researched and effective non-drug therapies for improving sleep:

Cognitive behavioral therapy for insomnia (CBT-I)

• This is considered the gold standard of treatment for chronic insomnia. It helps identify and reframe negative thoughts and behaviors that interfere with sleep. It has also been shown to be more effective than medication over the long term120,121.

Acupuncture

• This traditional Chinese practice has been shown to promote better sleep by helping to calm the nervous system and balance energy flow, with studies noting improved sleep onset and quality, particularly in people with chronic insomnia122.

Botanical therapies

Botanical therapies can be a valuable tool for supporting sleep by addressing root causes such as stress, inflammation, hormone imbalance, and nervous system dysregulation—helping the body restore its natural sleep rhythms.

If you’re considering botanical therapies, it’s important to know that more isn’t always better—don’t take every herb listed. For the safest and most effective results, especially if you're taking medications, consider working with a skilled practitioner who can help tailor the right approach for your unique needs.

Valerian root (Valeriana officinalis)

• Benefits: Can help reduce the time it takes to fall asleep and improve overall sleep quality, especially in individuals with mild insomnia123,124.
• Dosage: 400-600 mg of standardized extract.
• Frequency: 30-60 minutes before bedtime.
• Mechanism of action: Helps modulate GABA receptors in the brain, which in turn help regulate nervous system activity and promote relaxation, assisting the transition to sleep.

Chamomile (Matricaria chamomilla)

• Benefits: Known for its calming effects, chamomile may help reduce the time it takes to fall asleep and improve sleep quality123,125.
• Dosage: 1-2 cups of tea or 200-400 mg of extract.
• Frequency: Daily, 30-60 minutes before bedtime.
• Mechanism of action: Chamomile contains compounds that bind to benzodiazepine receptors in the brain, helping to promote relaxation and reduce central nervous system activity.

Passionflower (Passiflora incarnata)

• Benefits: Shown to help calm the mind, reduce the time it takes to fall asleep, and improve sleep quality126.
• Dosage: 250-500 mg of extract or 1-2 cups of brewed tea.
• Frequency: 30-60 minutes before bedtime.
• Mechanism of action: Supports GABA activity in the brain, which helps calm the nervous system and may ease the transition into sleep127.

Lavender (Lavandula angustifolia)

• Benefits: Shown to help improve sleep onset and quality and reduce nighttime waking123,126.
• Dosage: 80-160 mg of lavender oil capsule (oral), or consumed as tea, or as aromatherapy (2-3 drops essential oil via diffuser).
• Frequency: Once daily, ideally 30 minutes before bed.
• Mechanism of action: Helps modulate GABA receptors and calms the sympathetic nervous system with anxiolytic effects.

Lemon balm (Melissa officinalis)

• Benefits: Helps promote relaxation, mental clarity, and a calm mind. It also supports sleep quality; studies indicate it may help improve sleep disturbances in certain populations126,128.
• Dosage: 300-1,500 mg of extract, or consumed as tea.
• Frequency: One to two times daily, or 30-60 minutes before bedtime for sleep.
• Mechanism of action: Lemon balm influences GABA levels and has mild cholinergic activity, which are pathways associated with relaxation in the nervous system.

Ashwagandha (Withania somnifera)

• Benefits: Supports the body’s response to psychological stress and mood balance. May improve sleep quality, reduce the time it takes to fall asleep, and promote sleep efficiency126,129.
• Dosage: 300-600 mg standardized extract (5% withanolides).
• Frequency: Once or twice daily; often taken in the evening or divided between morning and evening.
• Mechanism of action: Acts as an adaptogen to help normalize cortisol rhythms by helping to modulate stress signaling pathways. It also supports GABAergic activity in the brain, which may help calm the nervous system and promote better sleep regulation130.

Supplements

Supplements can offer supportive tools for improving sleep, especially when used alongside lifestyle and behavioral strategies.

Please remember, before introducing a new supplement, it’s wise to speak with your healthcare provider. If you have a medical condition or are on medication, this step helps you stay safe and make sure everything works together to support your health.

Magnesium L-threonate

• Benefits: Magnesium helps support relaxation, cognitive function, and quality sleep; it may be helpful for those with stress-related sleep issues72,131.
• Dosage: 1,000-2,000 mg of magnesium threonate, roughly the equivalent of 72-144 mg of elemental magnesium. *Loose stools can be a sign that the supplement dose is too high; reducing it may improve tolerance.
• Frequency: Once daily, preferably in the evening.
• Mechanism of action: Crosses the blood-brain barrier and has been shown to raise brain magnesium concentrations, potentially helping to regulate the nervous system and improve sleep architecture.

Melatonin

• Benefits: Supports sleep onset, can be especially useful for jet lag, shift work, or delayed sleep phase132.
• Dosage: 0.3-3 mg.
• Frequency: 30-60 minutes before bedtime.
• Mechanism of action: Mimics the body’s natural melatonin release to help regulate circadian rhythm and help promote sleepiness.

L-theanine

• Benefits: Helps promote relaxation and may help improve overall sleep quality133,134.
• Dosage: 200 mg.
• Frequency: 30-60 minutes before bedtime.
• Mechanism of action: Helps balance the neurotransmitters associated with sleep. Studies indicate that supplementation with L-theanine may help promote alpha brain waves that are associated with relaxation.

Glycine

• Benefits: An amino acid that can help improve sleep quality and reduce sleep onset latency. May help improve sleep satisfaction, reduce fatigue, and optimize cognitive performance in sleep-restricted individuals135,136.
• Dosage: 3 grams.
• Frequency: Taken once daily, 30–60 minutes before bedtime.
• Mechanism of action: Glycine acts as an inhibitory neurotransmitter in the central nervous system, facilitating sleep onset and helping improve slow-wave sleep. It also may lower core body temperature, a physiological trigger for sleep initiation.

Tryptophan

• Benefits: An essential amino acid and serotonin precursor, may help improve sleep quality, increase total sleep time, and support mood regulation137,138.
• Dosage: 1-3 grams.
• Frequency: Once daily, 30–45 minutes before bedtime.
• Mechanism of action: Tryptophan can cross the blood–brain barrier, is then converted to 5-hydroxytryptophan (5-HTP), followed by serotonin and melatonin, helping regulate circadian rhythm and sleep.

Apigenin

• Benefits: A bioactive flavonoid found in chamomile, has been shown to have sedative and anxiolytic properties that may support improved sleep onset and maintenance139,140.
• Dosage: 25–50 mg apigenin or 125 mg of chamomile extract standardized to 20% apigenin.
• Frequency: Once daily, taken in the evening before bed.
• Mechanism of action: Apigenin binds to GABA receptors, promoting relaxation and sleep. It can also modulate brain-derived neurotrophic factor (BDNF) expression and may help balance cortisol, helping improve resilience to stress-related sleep disruption.

GABA (Gamma-aminobutyric acid)

• Benefits: A calming neurotransmitter in the brain, it can help the body relax by slowing down overactive brain signals. May support falling asleep faster, increasing the time in deep (NREM) sleep, and waking up feeling more rested141,142. It may also help lower stress and anxiety levels, improving mood and heart rate variability (HRV) in people who struggle with sleep143.
• Dosage: 100–300 mg.
• Frequency: Once daily, 30 minutes before bedtime.
• Mechanism of action: GABA can enhance parasympathetic nervous system activity and binds to GABA receptors, which may reduce nervous system excitability and promote calmness.

Phosphatidylserine (PS)

• Benefits: Can support stress reduction, sleep quality, and cognitive performance by helping modulate neurotransmitter balance. May also help normalize stress-induced cortisol elevations, improving relaxation and restorative sleep in individuals with chronic stress or insomnia144,145.
• Dosage: 100–400 mg.
• Frequency: Once daily in the evening, or divided into two doses with meals.
• Mechanism of action: Can help reduce hypothalamic-pituitary-adrenal (HPA) axis hyperactivation, thereby potentially lowering evening cortisol and supporting melatonin synthesis. It may also help improve neuronal membrane fluidity and neurotransmitter receptor function, which can contribute to sleep and mood regulation.

Omega-3 fatty acids (DHA and EPA)

• Benefits: May help improve sleep quality, reduce sleep disturbances, and support brain health by helping to balance inflammation78,79.
• Dosage: 1,000-2,000 mg.
• Frequency: Once daily, with meals.
• Mechanism of action: May reduce the production of certain inflammatory cytokines, support brain cell membrane function, and influence neuronal signaling, all of which may influence sleep regulation.

Vitamin D3

• Benefits: May help support better sleep by affecting several key systems in the body, including neurotransmitters that influence mood and relaxation, the immune system’s role in brain health, and supporting circadian rhythms73. Low levels of vitamin D have been associated with poor sleep quality and shorter sleep duration69,74.Dosage: 2,000-5,000 IU.
• Frequency: Once daily with a meal containing fat.Mechanism of action: Vitamin D3 receptors are found in areas of the brain that regulate sleep, helping to modulate the expression of genes involved in the sleep-wake cycle.

Light therapy

• For people with circadian rhythm sleep issues (like shift work disorder or delayed sleep phase), exposure to bright light in the morning may help reset the body’s internal clock and improve sleep timing146,147.

Mindfulness and meditation

• Practices like deep breathing, guided imagery, and mindfulness-based stress reduction may help reduce anxious thoughts and relax the body, making it easier to fall asleep and stay asleep148,149.

Yoga, Qigong, and tai chi

• These gentle movement practices combine breath, movement, and relaxation150. These have been shown to reduce sleep problems and improve sleep efficiency, especially in older adults151,152.

Physical activity and exercise

• Regular movement, especially moderate aerobic exercise like walking, swimming, or cycling, can improve both the ability to fall asleep and the quality of sleep itself. Exercise can help regulate the circadian rhythm, lower stress hormones, and promote the release of hormones that support relaxation and mood153,154. Keep in mind that exercising too close to bedtime may cause sleep disturbances; try to exercise two hours or more before bedtime.

Sleep medications: an overview

When sleep becomes a nightly struggle, a doctor may be able to uncover the root cause—and in some cases, sleep aids may be appropriate when other methods have been less effective. While prescription sleep aids, over-the-counter remedies, and even melatonin can play a role here, they are often best used as temporary tools—not long-term solutions. So when medications are used, the goal is to do so thoughtfully and with a plan for tapering as sleep improves naturally through diet, behavior, and targeted support.

Here's a summary of common sleep medications along with their pros and cons1,155:

• Antidepressants (e.g., trazodone)
  • Pros: Can address both depression and insomnia
  • Cons: Potential for weight gain, sexual side effects
• Antihistamines (e.g., diphenhydramine)
  • Pros: Over-the-counter availability; can help with occasional sleeplessness
  • Cons: Quick tolerance build-up, concerns of confusion, dizziness, and falls in older adults
• Non-benzodiazepine hypnotics (e.g., eszopiclone, zaleplon, zolpidem)
  • Pros: Less addictive than benzodiazepines; shorter half-life
  • Cons: Potential for complex sleep behaviors (sleep-walking, sleep-eating), morning grogginess
• Benzodiazepines (e.g., triazolam, temazepam, estazolam)
  • Pros: Effective for short-term insomnia; may reduce anxiety
  • Cons: Risk of dependency, daytime drowsiness, potential for cognitive impairment
• Melatonin receptor agonists (e.g., ramelteon)
  • Pros: Mimics natural sleep hormone; non-habit forming
  • Cons: Less effective for sleep maintenance; potential interactions with other medications
• Orexin receptor antagonists (e.g., suvorexant)
  • Pros: New class of medications; targets sleep-wake cycle
  • Cons: Expensive; potential for next-day drowsiness; can be habit-forming

All sleep medications should be taken under the guidance of a healthcare professional, as they can have side effects and interactions with other medications. Additionally, most are intended for short-term use and may not address the underlying causes of sleep issues156.

Function tests to assess sleep

Sleep doesn’t just affect how rested someone feels; it can also show up in lab work. When sleep is disrupted or chronically poor, it can influence hormone levels, immune markers, blood sugar control, and more. Laboratory testing may help uncover underlying issues that may be contributing to sleep problems.

• Thyroid (e.g., TSH, free T3, free T4): Measures thyroid function, which can impact sleep patterns and energy levels. An underactive or overactive thyroid can lead to trouble falling asleep, staying asleep, or waking too early157,158.
• Cortisol: This stress hormone test can reveal imbalances in the circadian rhythm. Imbalanced levels—too high at night or too low in the morning—can interfere with sleep cycles and potentially contribute to fatigue during the day159,160.
• Vitamin D (25-hydroxyvitamin D): Low vitamin D levels have been linked to poor sleep quality, shorter sleep duration, and increased risk of sleep disorders. This vitamin can also influence melatonin production73,74.
• Iron status (e.g., ferritin, serum iron, TIBC): Low iron or ferritin levels can be associated with restless legs syndrome or trouble falling asleep. Iron is needed to support dopamine function, which affects movement and arousal during sleep161,162.
• Blood glucose and HbA1c: Poor blood sugar control can lead to nighttime wakings, especially if levels drop too low15,163. Tracking fasting glucose and HbA1c may help uncover metabolic imbalances that can potentially disrupt sleep.
• High-sensitivity C-reactive protein (hs-CRP): This marker of inflammation may be elevated in those with obstructive sleep apnea or fragmented sleep, although there are many other causes of inflammation. Chronic inflammation can potentially worsen sleep quality and increase the risk of other health conditions164,165.
• Magnesium: This essential mineral plays a key role in helping to calm the nervous system and supporting deep, restorative sleep. Low magnesium levels have been linked to insomnia, nighttime awakenings, and restless sleep166,167.
• Sex hormones (e.g., estradiol, progesterone, testosterone): Hormonal fluctuations—especially during perimenopause or andropause—can disrupt sleep by affecting temperature regulation, mood, and melatonin levels168,169.

Other tests to assess sleep

Sleep assessment extends beyond blood tests. Various methods, from clinical studies to consumer wearables, offer different perspectives on sleep quality and patterns. These tools can help identify sleep disorders, track sleep-wake cycles, and monitor physiological changes during sleep84,170.

Clinical tests

• Polysomnography (PSG): This is the gold standard test for evaluating sleep disorders. Often done overnight in a sleep lab, this comprehensive test records brain waves, heart rate, breathing, oxygen levels, and body movements during sleep.
• Home sleep apnea test (HSAT): A simplified version of polysomnography done at home, this test monitors breathing and oxygen levels to screen for obstructive sleep apnea in low-risk individuals.
• Actigraphy: This non-invasive test uses a wearable device, like a wristwatch, to track sleep-wake patterns over days or weeks. It’s useful for identifying circadian rhythm issues, insomnia, or tracking sleep in the home environment.
• Multiple sleep latency test (MSLT): This test is done during the day to measure how quickly someone falls asleep in a quiet environment. It helps diagnose narcolepsy or excessive daytime sleepiness following an overnight PSG.
• Maintenance of wakefulness test (MWT): This measures a person’s ability to stay awake in a dark, quiet room. It’s often used for people in safety-sensitive jobs or those being treated for sleep disorders like sleep apnea.

Wearables

Wearable sleep trackers are becoming more popular tools for monitoring sleep patterns at home. These devices can provide helpful insight into sleep quality, total sleep time, heart rate, and even sleep stages—though they’re not as precise as clinical sleep studies.

• Smart rings: These lightweight rings monitor health data, including sleep stages, heart rate, temperature, and nighttime movement. They may provide sleep staging information and often a daily "readiness" score. They’re discreet and easy to wear, with some showing high sensitivity and specificity with close agreement with PSG171,172.
• Smartwatches: Worn on the wrist, smartwatches utilize accelerometers and heart rate monitors to track sleep duration, sleep stages, heart rate, and movement, while some may even include blood oxygen monitoring. They’re convenient and widely used but can vary in accuracy, especially in detecting lighter stages of sleep173,174.
• Fitness trackers: Fitness bands track similar sleep data to smartwatches and are often lighter and more discreet. They tend to do well with estimating total sleep time but may be less accurate with sleep staging than PSG174,175.
• Smart patches (e.g., wearable sleep stickers): These adhesive patches are worn like a sticker on the skin. It monitors sleep cycles, heart rate, and sometimes muscle activity. They’re noninvasive and useful for short-term tracking, though their use in long-term or clinical sleep assessment is still developing176.
• Smart mattress covers and under-mattress sensors: These devices track sleep without touching the body, measuring movements, heart rate, and breathing. Smart mattresses are often more accurate than wearables at detecting when a person falls asleep and wakes up during the night. They can be helpful for tracking long-term sleep habits, spotting unusual patterns, and improving the sleep environment, but may be less reliable in multi-sleeper beds or for lighter individuals177.

Key takeaways

• Sleep is a foundation of long-term health—just like nutrition and exercise. Consistently poor sleep increases the risk of many chronic diseases.
• Good sleep supports brain health, memory, and mood. During sleep, the brain processes memories and clears out waste through the glymphatic system, which is most active during deep sleep. This can help support cognitive health throughout the aging process.
• Sleep quality matters as much as sleep quantity. It's not just about how many hours of sleep one gets, but also the depth and regularity of sleep, including time spent in deep and REM sleep.
• Consistent sleep schedules support the circadian rhythm. Going to bed and waking up at the same time each day helps regulate the body’s internal clock and can improve sleep efficiency.
• Sleep hygiene is one of the most impactful non-drug practices for better sleep quality. Practices like limiting screen time before bed, creating a relaxing nighttime routine, and avoiding stimulants in the evening have shown measurable improvements in sleep quality.
• Various factors affect sleep quality, including lifestyle choices, environmental conditions, and one’s psychological state. Understanding and addressing these can significantly improve sleep.

Disclaimers

FUNCTION HEALTH IS A HEALTHCARE TECHNOLOGY COMPANY AND NOT A LABORATORY OR MEDICAL PROVIDER. ALL LABORATORY AND MEDICAL SERVICES ARE PROVIDED BY INDEPENDENT THIRD PARTIES. FUNCTION HEALTH DOES NOT OFFER MEDICAL ADVICE, LABORATORY SERVICES, A DIAGNOSIS, MEDICAL TREATMENT, OR ANY FORM OF MEDICAL OPINION, THROUGH OUR SERVICES OR OTHERWISE. FUNCTION HEALTH’S SERVICES ARE NOT A SUBSTITUTE FOR MEDICAL CARE, MEDICAL ADVICE, AND/OR A DETAILED DISCUSSION WITH YOUR PRIMARY CARE PHYSICIAN OR OTHER LICENSED PROVIDER. IF YOU HAVE ANY QUESTIONS REGARDING ANY LABORATORY RESULTS OR OTHER INFORMATION THAT YOU ACCESS THROUGH FUNCTION HEALTH, WE RECOMMEND THAT YOU DISCUSS THOSE QUESTIONS WITH A PRIMARY CARE PHYSICIAN OR OTHER LICENSED PROVIDER. ALL MATERIAL, INFORMATION, DATA, AND CONTENT THAT FUNCTION HEALTH PROVIDES IS STRICTLY FOR GENERAL INFORMATION PURPOSES.

WITHOUT LIMITATION, THE IDEAS AND INFORMATION PROVIDED IN THIS SLEEP HEALTH 101 GUIDE ARE STRICTLY FOR GENERAL INFORMATION PURPOSES AND DO NOT CONSTITUTE ANY FORM OF MEDICAL ADVICE OR A MEDICAL OPINION. EACH INDIVIDUAL, INCLUDING YOURSELF, PRESENTS A UNIQUE SET OF HEALTH REQUIREMENTS, RESTRICTIONS, LIMITS, AND OTHER NEEDS – IN ADDITION TO POTENTIAL ALLERGIES, AS WELL AS POSSIBLE CONTRAINDICATIONS WITH CURRENT MEDICATIONS – AND THIS SLEEP HEALTH 101 GUIDE DOES NOT ACCOUNT FOR THOSE INDIVIDUAL CIRCUMSTANCES. MOREOVER, SCIENTIFIC RESEARCH AND KNOWLEDGE ON THE TOPIC OF WEIGHT UNDERGO CONTINUOUS REASSESSMENT AND EVALUATION; FUNCTION MAKES NO WARRANTY REGARDING THE ACCURACY, RELIABILITY, EFFICACY, TIMELINESS, OR VALUE OF THE INFORMATION CONTAINED IN THIS SLEEP HEALTH 101 GUIDE. PLEASE CONSULT WITH YOUR PRIMARY CARE PHYSICIAN OR ANOTHER LICENSED MEDICAL PROVIDER BEFORE MAKING ANY CHANGES RELATING TO YOUR DIET, EXERCISE, SLEEP SCHEDULE, LIFESTYLE, MEDICATION REGIMEN, SUPPLEMENT INTAKE, AND/OR OTHER DAILY PRACTICES.