Why Good Sleep Matters: Benefits, Sleep Deprivation Risks, and What the Science Says

What is Sleep?

Sleep is a natural, reversible state of reduced consciousness and physical activity in which the body and brain undergo restorative processes. It is marked by altered brain activity, decreased responsiveness to external stimuli, and distinct stages, including non-REM and REM sleep. Sleep supports vital functions such as memory consolidation, tissue repair, immune regulation, and emotional processing.

An individual's chronotype—their natural tendency to be more alert in the morning or evening—is largely influenced by genetics [1] . Roughly 40% of people are morning types, meaning they wake up early and tend to be most productive in the morning. About 30% are evening types, whose biological clocks are naturally shifted later, making them more alert and focused at night [1] . The remaining 30% fall somewhere in between, often leaning slightly toward eveningness [1] .

Cognitively, sleep strengthens memory, learning, and decision-making, while recalibrating emotional balance and enhancing creativity—especially during dreaming [2]. Physiologically, it supports immune defence, metabolic regulation, cardiovascular health, and gut function [3] [4] [5] . Sleep also modulates blood pressure and reduces inflammation [6] [7]. Compared to diet and exercise, sleep may exert a broader, more systemic influence on overall health.

A brief physiology [1]

There are two key factors that regulate sleep and wakefulness, circadian rhythm and sleep pressure.

Graph: The Two Factors Regulating Sleep and Wakefulness

Credit: Why We Sleep: Unlocking The Power of Sleep and Dreams.

Circadian rhythm

The circadian rhythm (also called Process-C), regulated by the brain’s suprachiasmatic nucleus (SCN), controls daily cycles of sleepiness and alertness. Beyond sleep, it also influences a wide range of essential functions such as eating patterns, mood, metabolism, hormone release, physical performance, and can affect the timing of birth and is linked to time of death. On average, the human circadian rhythm runs slightly longer than a day—about 24 hours and 15 minutes.

Graph: Typical 24 hour circadian rhythm (core body temperature)

This graph shows one of the physiological changes regulated by the SCN: body temperature fluctuates independently of whether a person is awake or asleep.

Credit: Why We Sleep: Unlocking The Power of Sleep and Dreams.

To stay aligned with the 24-hour day, the brain relies on external cues known as zeitgebers (German for “time givers”). Sunlight is the most powerful zeitgeber, helping reset and synchronize the circadian clock each day. Other zeitgebers include food intake, exercise, temperature changes, and social interactions, all of which help fine-tune our internal rhythms to match the external world.

Graph: The Urge to Be Awake

This graph illustrates Process-C, the circadian rhythm of alertness, which peaks in the early afternoon—boosting energy levels—and is strongest just before waking. It gradually declines throughout the day, reaching its lowest point at night.

Credit: Why We Sleep: Unlocking The Power of Sleep and Dreams.

Sleep pressure

Sleep pressure (also called Process-S) is a physiological urge to sleep, driven by the gradual buildup of adenosine. As adenosine levels rise, it gradually lowers activity in brain areas that keep us alert while increasing signals that promote sleep—usually leading to a strong need for rest after 12 to 16 hours of wakefulness. This signal can be temporarily blocked by caffeine, which prevents adenosine from binding to its receptors.

Graph: The Urge to Sleep

This graph shows that by late evening, rising adenosine levels and a declining circadian rhythm work together to produce a powerful drive to sleep.

Credit: Why We Sleep: Unlocking The Power of Sleep and Dreams.

Although these two systems operate independently, they normally work together to regulate sleep and wakefulness. Sleep occurs when rising sleep pressure aligns with a natural dip in circadian alertness. The wider the gap between high adenosine levels and low circadian alertness, the stronger the drive to sleep. Sleep then acts as a reset mechanism, clearing adenosine and restoring the brain's capacity for another full cycle of wakefulness. In contrast, inadequate or poor-quality sleep results in residual adenosine, leading to increased daytime sleepiness.

Sleep cycle

Sleep unfolds in a 90-minute cycle of non-rapid eye movement (NREM) and rapid eye movement (REM) stages, in which NREM can be further divided into 4 stages. Early in the night, NREM sleep dominates, while REM sleep increases in the second half, creating an uneven ratio across cycles.

Graph: The Architecture of Sleep

Credit: Why We Sleep: Unlocking The Power of Sleep and Dreams.

Brainwave is another way to reveal which state of sleep you are in. During wakefulness, the brain shows fast and irregular electrical activity as it processes various types of information. In deep NREM sleep, brainwaves slow down and become more regular. Short bursts of activity, known as sleep spindles, help maintain sleep by reducing sensitivity to external noise. This stage supports the transfer of memories from short-term to long-term storage.

In REM sleep, brain activity becomes fast and irregular again, similar to wakefulness. The body is temporarily paralyzed by signals from the brainstem, preventing movement during dreaming. During this stage, the brain focuses on internal signals, and vivid dreams are most likely to occur.

Graph: The Brainwaves of Wake and Sleep

Credit: Why We Sleep: Unlocking The Power of Sleep and Dreams.

Melatonin

Melatonin is a hormone released by the pineal gland in response to darkness. It acts as a signal that it's nighttime, helping the brain and body know when to prepare for sleep. While melatonin helps regulate when sleep happens, it doesn’t actually create sleep itself. In the morning, light exposure suppresses melatonin production, signaling the body that it's time to wake up.

Graph: The cycle of melatonin

This graph shows that melatonin levels rise a few hours after dusk, peak around 4 a.m., and decline as dawn approaches.

Credit: Why We Sleep: Unlocking The Power of Sleep and Dreams.

A brief history

In 1729, French scientist Jean-Jacques d'Ortous de Mairan conducted a fascinating experiment with Mimosa pudica—a plant known for its leaves that open during the day and close at night [1]. This daily movement, later called “sleeping leaves” by Charles Darwin, appeared to follow the sun.

At first, de Mairan observed the plant under natural sunlight and darkness. As expected, the leaves opened during the day and folded at night. But the real breakthrough came when he placed the plant in total darkness for 24 hours. To his surprise, the leaves continued to open and close as if the sun were still rising and setting. This showed, for the first time, that living things have an internal biological clock that keeps time even without external light cues.

Over 200 years later, in 1938, American physiologist Nathaniel Kleitman and his assistant Bruce Richardson tested whether humans also had such internal clocks [8]. They spent 32 days in total darkness inside Kentucky’s Mammoth Cave. The results were striking: both men maintained a daily rhythm without sunlight. Richardson, in his 20s, followed a 26–28 hour cycle, while Kleitman, in his 40s, showed a rhythm of just over 24 hours.

These experiments revealed that humans—like plants—have a self-generated circadian rhythm. It runs slightly longer than a 24-hour day and varies with age.

In 1952, American sleep researcher Eugene Aserinsky and physiologist Nathaniel Kleitman used Polysomnography (PSG), a scientific gold standard for confirming sleep by recording brainwave activity, eye movement, and muscle activity using electrodes, observed that infants’ eyes darted rapidly during certain sleep phases, accompanied by active brainwaves similar to wakefulness, while other periods showed calm eyes and slower brainwaves. This study led to the identification of two distinct sleep types: NREM sleep and REM sleep.

Anthropology, sociology, art, and more…

Sleep habits vary widely across cultures. Anthropologist Marcel Mauss observed a range of global practices: some people sleep on the floor, others in hammocks, and the Masai of East Africa are even known to sleep while standing [9]. In Kenya, the Ciabra tribe separates sleeping arrangements by gender; the Aché people in Paraguay use mats, while the Efe in Zaire rest on leaves [10] [11] .

Brigitte Steger and Lodewijk Brunt identified three primary cultural patterns of sleep: monophasic, biphasic, and polyphasic [12].

• Monophasic Sleep involves a single, consolidated sleep period—typically eight hours at night. This pattern is common in the U.S. and Northern Europe. Daytime sleep is usually discouraged, except for children, the elderly, or night-shift workers. The rise of this pattern is closely linked to industrialization, which reshaped work schedules and reinforced cultural ideals of productivity and privacy.
• Biphasic Sleep includes a longer sleep at night and a shorter nap in the early afternoon (siesta). It is typical in countries like Spain and parts of South America. The siesta helps accommodate late-night social activity and boosts daytime performance. However, this pattern is declining due to globalization, economic demands, and modern ideals that associate napping with laziness or inefficiency.
• Polyphasic Sleep consists of several sleep periods spread throughout the day and night. It includes a core nighttime sleep and flexible daytime naps. This pattern is common in various parts of the world and includes culturally specific practices like Japan’s inemuri—a socially accepted form of dozing in public spaces while remaining socially "present." While polyphasic sleep can enhance adaptability and alertness, it is not universally accepted and varies greatly between cultures.

Art work: The Harvesters

Credit: Dutch artist Pieter Breughel the Elder

Beyond cultural differences, modern technology—especially artificial lighting—has profoundly influenced sleep behavior. Before the invention of electric power stations (like Edison’s in London in 1882), daily activities typically ended at sunset due to limited light sources. Among hunter-gatherer societies like the Hadza and San, nighttime activities were brief and centered around communal fires, often involving storytelling or singing [13] [14].

The introduction of candles, gas lamps, and oil lamps allowed for extended evening activities. For example, Pierre-Auguste Renoir’s painting Bal du moulin de la Galette captures scenes of working-class Parisians dancing and socializing under the warm glow of early street lamps.

Art work: Bal du moulin de la Galette

Credit: Pierre-Auguste Renoir

The late 19th century saw the widespread adoption of electric lighting—first with mass-produced light bulbs in the 1870s, then fluorescent lighting in the 1880s [1]. These developments further extended nighttime activity and began to interfere with natural sleep cycles. Artificial light disrupts the body’s circadian rhythm by confusing the brain’s SCN, which controls the release of melatonin, the hormone that signals sleep. Exposure to artificial light delays melatonin production and shifts the body’s internal clock, altering traditional sleep patterns.

Mainstream vs. Alternative Views

Mainstream

According to the American Academy of Sleep Medicine (AASM) and the Sleep Research Society (SRS), adults should aim for at least seven hours of sleep per night to maintain optimal health [15]. Sleep plays a critical role in physical and mental well-being; research links insufficient sleep to a wide range of health issues, including hypertension, obesity, type 2 diabetes, impaired immune function, cardiovascular disease, mood disorders, neurodegenerative conditions, dementia, and even loneliness [16]. Beyond these broad health outcomes, researchers are increasingly interested in how sleep affects specific biological processes, including metabolism, hormone regulation, immune response, and gene expression. These underlying mechanisms help explain why even moderate sleep loss can have far-reaching consequences on long-term health.

Melatonin supplements are commonly used to treat sleep difficulties, especially in individuals over the age of 55 or in those with chronic insomnia or circadian rhythm disorders, such as jet lag or shift work disorder [17].

Alternative

While mainstream approaches tend to emphasize sleep quantity—such as achieving a consistent seven to eight hours per night—alternative perspectives focus on sleep quality, flexibility, and alignment with individual natural rhythms.

One well-known advocate is cognitive neuroscientist Sara Mednick, who promotes napping as a powerful tool for mental and physical restoration. She describes naps as a “miracle drug” that enhance alertness, creativity, memory, and emotional regulation, all without the side effects of stimulants like caffeine [18]. Mednick highlights a natural afternoon dip in alertness, typically between 2:00 and 3:00 p.m., during which a short nap can significantly boost cognitive function—often more effectively than a cup of coffee [19] [20].

In the era of biohacking and self-tracking, smart devices have become increasingly popular tools for optimizing sleep. Products like the Oura Ring, developed and popularized by wellness entrepreneur Dave Asprey, track physiological indicators such as heart rate variability, body temperature, blood oxygen levels, and sleep stages to generate personalized sleep scores [21]. These insights help users understand how factors like stress, diet, and exercise impact their rest.

Another popular tool is the Whoop, a wrist strap founded by former collegiate athlete Will Ahmed [22]. It monitors sleep, recovery, and daily strain, translating data into practical recommendations for improving routines and managing stress [22]. Similarly, the Sleep Analyzer Mat by French digital health company Withings provides a contactless solution, placed under the mattress to monitor snoring, sleep apnea, heart rate, and sleep cycles—offering a comprehensive picture of sleep health without the need to wear a device [23]. These tools appeal to individuals seeking data-driven, non-pharmacological approaches to improving their sleep.

Beyond tech, natural remedies also play a role in alternative sleep strategies. Aromatherapy—using essential oils such as lavender, chamomile, and cedarwood—is often employed to create a soothing sleep environment, either through diffusers or by applying oils to pillows and linens. These practices are frequently integrated into broader holistic health systems like Ayurveda and Traditional Chinese Medicine (TCM), which include treatments such as acupuncture, massage, and cupping aimed at restoring balance and improving sleep.

Certain nutrients, such as magnesium, are recognized for their role in improving sleep health, as highlighted by experts like Dr. Rhonda Patrick [24]. Magnesium naturally regulates two key brain chemicals: N-methyl-D-aspartate (NMDA) and γ-aminobutyric acid (GABA). These chemicals are crucial for maintaining stable sleep patterns. Magnesium gently blocks NMDA receptors while boosting GABA activity, which allows more potassium to enter cells—promoting relaxation and supporting better quality sleep.

Moreover, L-Theanine—a water-soluble, non-proteinogenic (means not used to build proteins) amino acid primarily found in tea leaves—has been shown to influence levels of dopamine, serotonin, and GABA, which are key neurotransmitters involved in mood and sleep regulation [25]. It has been suggested to support improved sleep quality by promoting relaxation without sedation. Advocates like author and biohacker Ben Greenfield have highlighted its role in reducing stress and enhancing calmness, making it a popular supplement in sleep and recovery routines [26].

Some nutrients are attracting growing interest for their potential roles in sleep health, beyond their widely recognized functions. Creatine, best known as a workout supplement for enhancing physical performance, is now being studied for its ability to counter brain energy deficits caused by sleep deprivation—highlighting its promise in supporting cognitive resilience and mental clarity [27] [28]. Likewise, glycine, a key amino acid in collagen and often linked to bone health, also plays a critical role in the central nervous system, and may contribute to better sleep quality by promoting relaxation and regulating core body temperature [29].

A growing movement also challenges rigid sleep-wake schedules dictated by traditional work structures. Experts like German chronobiologist Till Roenneberg, British neuroscientist Matthew Walker, and circadian researcher Russell Foster argue for work environments that respect individual circadian rhythms. They critique the modern 9-to-5 schedule as misaligned with many people’s natural sleep patterns—particularly night owls, who often suffer both performance deficits and long-term health consequences when forced into early-morning routines [1] [30] [31].

What does science say?

Nearly 1 in 5 people in the UK aren’t getting enough sleep, and about one-third of American adults fail to meet the recommended 7 hours per night on average [32] [33]. Sleep deprivation is becoming increasingly common in modern societies and often goes unnoticed—despite its significant impact on both individual and public health.

For example, people trying to lose weight may find that sleep deprivation undermines their efforts. When the body is sleep-deprived, it tends to burn muscle instead of fat, making dieting less effective [1]. Even short-term sleep loss can disrupt blood sugar regulation and reduce physical performance, even in otherwise healthy individuals [34] [35].

The consequences of sleep deprivation extend beyond personal health to public safety. Fatigue is a contributing factor in an estimated 20% of car accidents in the UK, US, and EU [36] [37] [38] .

Since melatonin is classified as a natural supplement rather than a medication in many countries, its sale is often poorly regulated, and dosage consistency can vary significantly. One study found that the actual melatonin content in over-the-counter supplements ranged from 83% less to 478% more than what was listed on the label [39].

While melatonin is generally considered safe for short-term use, its long-term effects remain uncertain. It can interact with medications and may influence cardiovascular, reproductive, endocrine, and metabolic systems in healthy individuals. However, its effects on people with chronic health conditions—such as heart disease, diabetes, or cancer—are still unclear [40].

Napping has long been praised for its cognitive and emotional benefits. Research consistently highlights its role in memory consolidation, preparation for new learning, enhanced executive functioning, and improved emotional regulation [41]. These advantages have led some experts to describe napping as a powerful tool for mental and physical restoration.

However, the benefits of napping are not universal. A growing body of research reports a paradox, particularly in older adults: frequent daytime naps have been linked to negative health outcomes, including cognitive decline, hypertension, and type 2 diabetes [42]. This suggests that the health impact of napping may depend on age, health status, and frequency. While the possibility of reverse causality has been noted, further research is needed to determine the direction and strength of this relationship.

One emerging hypothesis proposes that inflammation may mediate the link between frequent napping and poor health outcomes [41]. In environments with high exposure to infectious diseases, mid-day sleep (or siestas) may have evolved as an adaptive response. Sleep has been shown to aid immune function and support fever generation during infection, which suggests that increased daytime sleep might reflect underlying immune responses rather than directly causing negative effects [43] [44].

The rise of digital health technologies has revolutionized how people manage sleep. Smart devices have made sophisticated health tracking more accessible and affordable. These tools provide real-time data on heart rate, sleep stages, body temperature, and more, enabling users to monitor their sleep without needing a clinical setting [45]. Despite their popularity, the accuracy of these devices remains a concern. One study found that commonly used wearables were not reliable for measuring the timing and duration of sleep in real-world conditions [46]. Improvements in multi-state sleep categorization are needed, and clear guidelines must be established for their effective and valid use.

Aromatherapy has shown promise in improving sleep quality, especially among older adults, patients with chronic illnesses, and those with sleep disorders [47] [48] [49]. However, the effectiveness of aromatherapy can vary based on individual factors. For instance, studies show limited benefit for children with autism spectrum disorders [50] [51]. Similarly, other alternative therapies—such as cupping, acupuncture, massage, and treatments from Ayurvedic and TCM—are widely practiced but still require more rigorous scientific evaluation to determine their efficacy.

A systematic review of nine studies on magnesium and sleep health concluded that well-designed randomized controlled trials (RCTs) are still needed, as most existing evidence is observational [52]. While magnesium supplementation appears to improve sleep quality, the exact mechanisms remain unclear. Magnesium is known to enhance GABA activity, but deficiency is also associated with chronic inflammation and oxidative stress caused by sleep deprivation [53]. Adding complexity, another study found that long-term sleep deprivation significantly reduces magnesium levels in red blood cells, highlighting ongoing debate about the direction and nature of this relationship [54].

A systematic review of 19 studies explored the potential of L-theanine in managing sleep disturbances, but emphasized the need for further research specifically on “pure” L-theanine supplements [25]. Meanwhile, individuals with insufficient creatine intake have been found to show a higher prevalence of sleep disorders compared to those who meet recommended levels [55]. Glycine has also gained attention for its potential to reduce sleepiness and fatigue caused by sleep restriction, likely by indirectly modulating neuropeptides in the suprachiasmatic nucleus (SCN) [56]. However, many studies rely on subjective measures, raising the possibility of a placebo effect [57]. The growing interest in these nutrients reflects a broader shift toward gentler, food-based strategies for improving sleep—offering a promising alternative to medications that often come with significant side effects.

Night owls often struggle with early mornings because key areas of their brain—especially the prefrontal cortex—remain in a sleep-like state. The prefrontal cortex is responsible for high-level thinking, logical reasoning, and emotional regulation [58]. Even if night owls are physically awake, this part of the brain can remain sluggish or "offline" during early hours, making it harder to focus, make decisions, or stay emotionally balanced.

Who it might help/harm?

General population

National organizations usually suggest at least 7 hours sleep per night ,which might vary by age, health condition and personal circumstances [59] [60] [61] [62].

People Most Affected by Jet Lag (e.g., Long-Haul Flight Crews)

Jet lag is a temporary sleep disorder caused by rapid travel across time zones, which disrupts the body’s internal circadian clock. Symptoms can last for several days after arrival, as the SCN adjusts slowly, typically by about one hour per day [1].

Traveling east is generally harder than traveling west because falling asleep earlier is more difficult than staying awake later. This aligns with our natural circadian rhythm, which runs slightly longer than 24 hours, making it easier to adapt to longer days (westward travel) than shorter ones (eastward travel).

Frequent jet lag can take a toll on both the brain and body, and has been linked to shrinkage in memory-related brain areas, short-term memory problems, and increased risks of cancer and type 2 diabetes [1] [63] [64] [65].

Caffeine drinkers

Caffeine is a natural stimulant that works by blocking adenosine receptors in the brain, which temporarily reduces sleep pressure and increases alertness [1]. It's commonly found in coffee, tea, chocolate, energy drinks, and cola-type beverages. While caffeine can help people feel more awake, consuming large amounts—especially later in the day—can lead to insomnia. Sensitivity to caffeine varies from person to person, influenced by genetics and age [66].

Caffeine typically reaches its peak level in the bloodstream about 30 minutes after consumption. However, its half-life is 5 to 7 hours, meaning it stays in the body much longer. For instance, drinking coffee at 7:30 p.m. can leave half the caffeine still active by 1:30 a.m., disrupting sleep quality.

NASA research found that spiders given caffeine struggled to build normal webs—performing worse than spiders given LSD or other drugs [67]. Even tiny amounts of caffeine disrupted their ability to spin webs properly.

Alcohol drinkers [1]

Alcohol acts as a sedative, calming your brain by slowing down nerve activity. It starts by relaxing the prefrontal cortex, the part of your brain that controls impulses, which is why you might feel more social and less inhibited after a drink. Many people think alcohol helps them sleep better, but that’s a myth—it doesn’t help you fall asleep easily or improve your sleep quality. But this isn’t real sleep; it’s more like a light form of anesthesia, not the natural, healthy rest your body needs.

Alcohol also messes up your sleep in big ways. It breaks your sleep into pieces with short awakenings you might not even notice, leaving you feeling unrested. Even worse, it drastically cuts down on REM sleep, the dreaming stage that’s crucial for your brain. For heavy drinkers, alcohol can wipe out REM sleep completely, causing serious issues like hallucinations or a condition called delirium tremens, where the brain gets overwhelmed. Once alcohol is metabolized and cleared, the brain attempts to recover lost REM sleep through a “REM rebound,” resulting in intense, vivid, and sometimes wild dreams later in the sleep cycle.

This lack of REM sleep doesn’t just hurt your memory—it also makes you feel less refreshed and sleepier during the day. Plus, alcohol can leave a lingering effect, almost like a “digital hangover,” disrupting your sleep for days after you drink.

People with sleep disorders

People who suffer sleep disorders should seek professional evaluation to determine the underlying causes and receive appropriate treatment. Depending on the diagnosis, interventions may include cognitive behavioral therapy for insomnia (CBT-I), lifestyle adjustments, medical treatments, or the use of carefully monitored sleep aids. Early intervention can significantly improve quality of life, cognitive functioning, and overall health.

How to stack it?

Having good sleep hygiene can help you have a good night's sleep.

Avoid the modern light [1]

Brain’s internal clock, the SCN, is regulated by light, particularly blue light. Natural darkness signals the release of melatonin, promoting sleep. But artificial light messes with this process, delaying melatonin release by 2–3 hours and making it harder to fall asleep.

Even a soft glow, like from a bedside lamp (20–80 lux), can lower melatonin levels a lot. Things got worse with blue LED lights, which are found in devices like smartphones and tablets. These emit blue light that slows down melatonin production and harms your sleep quality.

Here’s what you can do:

• Use dim, warm-colored lights in the evening.
• Skip bright overhead lights.
• Wear blue-light-blocking glasses in the evening.
• Put up blackout curtains to keep your room dark.
• Add software to your devices to cut down on blue light at night.

Avoid alcohol [1]

Drinking even a moderate amount of alcohol in the evening can disrupt your sleep quality and affect how well your brain processes memories. For the best sleep health, it’s recommended to avoid alcohol at night altogether.

Cooler the room [1]

For the best sleep, your body needs to cool down by about 1°C (2–3°F). A cool room helps kick start this process, making it easier to drift off. The perfect bedroom temperature for most people is around 65°F (18.3°C), though it can vary depending on your age, gender, or personal comfort.

Your hands, feet, and head are key players in releasing heat to cool your core. Simple habits like splashing water on your face or letting your arms and legs peek out from under the covers can naturally boost this cooling. A hot bath before bed can also help—though you might think it works because it warms you up, it actually brings blood to your skin’s surface. When you step out, the heat escapes, your core temperature drops, and you fall asleep faster.

Make a schedule [1]

Sticking to the same wake-up time every day, even on weekends, can help keep your sleep schedule steady and improve sleep, especially if you have insomnia—though it often means using an alarm.

Alarms can be tough on your body, causing a sudden spike in blood pressure and heart rate by activating your fight-or-flight response. Hitting the snooze button makes it worse, repeatedly stressing your heart and nervous system, particularly if you do it daily. To avoid this strain, skip the snooze and wake up just once.

Common questions

Can melatonin supplement help solve insomnia?

Melatonin supplements can help with certain types of sleep issues, but they are not a universal solution for insomnia.

What they can help:

• Jet lag – help reset internal clock when crossing time zones
• Delayed sleep phase syndrome – for “night owls” who have trouble falling asleep at a typical bedtime
• Shift work – can support adjusting to irregular work hours
• People with specific conditions shows declines in melatonin production – older adults with age-related insomnia, children with autism spectrum disorder and ADHD [68]

What they can’t help:

• General insomnia – this includes trouble falling/staying asleep without a clear timing issue
• Stress- or anxiety-related insomnia
• Poor sleep habits – melatonin cannot override screen time, caffeine effect, irregular schedule etc.

How do I know if I got enough sleep?

Here are two quick questions to help you figure it out:

• Could you fall back asleep at 10 or 11 a.m., just a few hours after waking?

If yes, that’s a strong sign you didn’t get enough sleep—either in quantity or quality.

• Can you get through the morning without needing caffeine?

If not, there’s a chance you’re using caffeine-contained foods or drinks to cover up regular sleep deprivation.

Still unsure? Try these bonus checks:

• Would you sleep past your usual wake-up time if you didn’t set an alarm?

If so, your body’s probably asking for more sleep than you’re giving it.

• Do you catch yourself rereading the same sentence multiple times while working or studying?

Classic tired-brain move. It usually means you’re running low on mental energy from not sleeping enough.

• Ever forget what color the last few traffic lights were while driving?

That might feel like distraction, but it can actually be a red flag for sleepiness.

The SATED sleep health questionnaire, developed by sleep scientist Daniel Buysse, assesses five key aspects of healthy sleep: Satisfaction, Alertness, Timing, Efficiency, and Duration [69]. It’s a simple yet effective tool for evaluating your sleep quality.

Table: SATED sleep health questionnaire

Credit: Sleep health: can we define it? Does it matter?

Getting enough good sleep really does make a difference in how you think, feel, and function—so it’s worth paying attention to these little clues!

This article is for informational purposes only and does not constitute medical advice. Consult a healthcare provider before making changes to your health routine.