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Excessive Daytime Sleepiness — From Causes to Cures

Woman asleep with head on kitchen counter a sign of excessive daytime sleepiness

It’s natural to feel sleepy during your afternoon dip and when bedtime arrives. What’s not natural, though, is feeling drowsy for most of the day. If you are, you may be dealing with excessive daytime sleepiness (EDS).

Call it whatever you will — drowsiness, sluggishness, tiredness — EDS makes you feel like you're running on a low battery as you struggle to get through the day. But you're not alone, as studies show 9-28% of the general population is caught in the claws of excessive sleepiness.

As a prevalent public health issue with serious consequences for the individual and society, it's time to learn all about EDS and how you can manage it to optimize every aspect of your waking life, from performance boosts to improved well-being.

Please note: This post is meant for informational purposes only and should not replace medical advice from a health care professional. While the RISE app is designed to support natural sleep and boost sleep hygiene to address symptoms of sleep deprivation like EDS, it does not treat medical conditions such as sleep disorders or neurological disorders.

Excessive Daytime Sleepiness in a Nutshell 

Did you know EDS isn't a sleep disorder in itself? Rather, it's a symptom of sleep deprivation. The International Classification of Sleep Disorders defined excessive daytime sleepiness (EDS) as “the inability to stay alert and awake during the major waking episodes of the day, resulting in unintended lapses into sleep.” In that sense, EDS is characterized by persistent drowsiness, which is vastly different from the occasional yawn during your energy dips (more on that later).

On top of its trademark sleepiness, EDS may also cause:

  • A lack of energy or tiredness
  • More intense sleep inertia (i.e., you feel groggier for longer upon waking up)
  • Difficulty focusing or staying alert
  • Making more mistakes than usual
  • Poorer decision-making
  • Impaired memory
  • Slower reaction times or a feeling of sluggishness
  • Increased irritation, stress, anxiety, and depression
  • Sleep attacks (in medical conditions like narcolepsy)

If you’ve experienced one or more of the above symptoms almost every day for at least three months, there’s a high chance you’re under the duress of EDS.

The Miscreants of Excessive Daytime Sleepiness

Excessive daytime sleepiness: A man works on a computer at night

EDS is mainly driven by sleep insufficiency, but in some cases, excessive sleepiness is a byproduct of an underlying medical condition. With countless potential causes, it can be difficult to resolve excessive sleepiness without an accurate diagnosis.

It probably comes as no surprise that sleep deprivation is the No. 1 cause of EDS. Not meeting your sleep need means you’re accumulating sleep debt — the amount of sleep you’ve owed your body over the past 14 days. Even a small amount of sleep debt is capable of infusing your system with daytime drowsiness.

Similarly, circadian rhythm sleep disorders (CRSD) — a misalignment between your biological sleep-wake cycle and your actual sleep schedule — are common contributors to EDS. Examples of CRSDs are jetlag and shift work disorder (SWD). For CRSD, excessive sleepiness may not necessarily rear its head during the daytime. To illustrate, night shift workers battling SWD will likely feel drowsy during their working hours in the middle of the night.

EDS is also strongly associated with sleep, mood, mental, and central nervous system disorders, such as:

  • Obstructive sleep apnea (OSA), where your airway is restricted during sleep and disrupts your breathing
  • Insomnia, which is difficulty falling asleep and/or staying asleep
  • Idiopathic hypersomnia, which is an intense urge to nap even after meeting your sleep need
  • Parasomnia, which are unusual behaviors like sleepwalking that can occur at any stage of the sleep cycle
  • Narcolepsy with or without cataplexy (or muscle weakness), which causes overwhelming daytime drowsiness
  • Restless legs syndrome, which causes uncontrollable leg movement and/or uncomfortable lower body sensations
  • Periodic limb movement disorder, which causes repeated leg cramping or jerking during sleep
  • Mood disorders, including depression and anxiety
  • Mental disorders, like post-traumatic stress disorder (PTSD) and schizophrenia
  • Neurological disorders, like Parkinson's disease and dementia
  • Metabolic health problems, such as hypothyroidism

On top of that, certain medications, such as sedatives and antidepressants, come with drowsiness as a side effect. Ironically, these sleep-inducing medications are also used to address some of the above medical conditions, further compounding the issue of EDS. For example, benzodiazepine, which tackles chronic insomnia, heightens daytime drowsiness and suppresses rapid eye movement (REM) sleep.

Certain risk factors also predispose you to excessive sleepiness, including:

  • Sleep deprivation (due to insufficient sleep or sleep loss)
  • Anxiety
  • Depression
  • Insomnia
  • Obesity
  • Smoking
  • Certain ages (i.e., teenagers, young adults, and elderly people)

Measuring Excessive Daytime Sleepiness: A Gnarly Issue

When asked to describe symptoms of EDS, most patients tend to throw around words like “tiredness,” “a lack of energy,” and “difficulty concentrating.” Consequently, it can be hard to pinpoint EDS, much less measure its severity.

That said, the Epworth Sleepiness Scale (ESS) and the Multiple Sleep Latency Test (MSLT) are the two most common tools for diagnosing EDS.

The ESS is a simple questionnaire to determine your sleepiness in eight different situations, like reading and driving. The results may range from 0 (no daytime sleepiness) to 24 (maximum daytime sleepiness). Usually, an ESS score greater than 10 indicates abnormal sleepiness.

On the other hand, the MSLT is “an objective test that measures the tendency to fall asleep under controlled conditions.” It’s usually performed with polysomnography (a comprehensive sleep study) when diagnosing narcolepsy and idiopathic hypersomnia.

The results of MSLT are categorized as such:

  • Less than 15 minutes: Mild sleepiness
  • Less than 10 minutes: Moderate sleepiness
  • Less than 5 minutes: Severe sleepiness

Do note that either assessment method may be implicated by individual factors such as sleep debt, sleep need, and sleep hygiene.

The Debilitating Impacts of Excessive Daytime Sleepiness

Excessive Daytime Sleepiness: A child sleeps in class

If you’re only a little bit tired, you’re already suffering from cognitive and emotional decline, possibly jeopardizing your personal safety. In fact, William Dement, a founder of the field of sleep medicine, had a mantra: "Drowsiness is a red alert." If you find that a little dramatic, picture yourself behind the wheel on a busy highway, and you'd soon find Dement's statement isn't overly cautious at all. As such, imagine the wide-reaching repercussions EDS can have on your daily life.

Deeper scrutiny of the current scientific literature on daytime drowsiness produces more worrying insights — some of which you may personally relate to:

Through the cultural and societal lens, people with EDS are often viewed as “lazy.” This opens up a new can of worms in the form of reduced psychological well-being. A 2014 study confirmed narcolepsy patients struggle more with “vitality, physical well-being, relations with friends and leisure activities, especially in adolescents.” Another systematic analysis surveyed 297 subjects with narcolepsy and discovered they are more likely to entertain depressed, suicidal thoughts.

While you may chalk up persistent drowsiness to insufficient sleep the night before, EDS isn’t something to sweep under the rug. Yes, the physical, emotional, and mental costs are more than hefty. But, it also affects the people around you. Picture this: Falling asleep at the wheel with your 4-year-old son strapped in his car seat. Not only is this dangerous for you and your son, but it puts others on the road in danger as well.

How to Manage Excessive Daytime Sleepiness

Before you resign yourself to a lifelong fate of intense sleepiness, rest assured there's light at the end of the tunnel. It all begins with reviewing your sleep debt, working with your circadian rhythm, and reaching out to a health care professional if need be.

Refine Your Sleep Hygiene With the Two Laws of Sleep

RISE app screenshot showing how much sleep debt you have
The “Sleep” tab in the RISE app shows your running sleep debt over the past 14 days.

Since the most common cause of EDS is sleep deprivation, you can take action, starting right now, to get enough sleep. It all boils down to improving your sleep hygiene to account for what we at Rise Science call the Two Laws of Sleep, a theory scientifically known as the two-process model of sleep regulation first established by sleep scientist Alexander Borbély in the 1980s. The Two Laws of Sleep focus on:

  • Keeping sleep debt low
  • Working with your circadian rhythm

Before we go any further, let us clarify that everyone naturally has two energy dips during the day. Courtesy of your circadian rhythm — your body’s internal clock — you’ll feel less awake during the afternoon dip and when bedtime approaches. These two energy dips will happen even if you've met your sleep need and maintained circadian alignment (although a high sleep debt and circadian misalignment will undoubtedly worsen your drowsiness during these two windows of time).

That’s why we’ve created a comprehensive Sleep Guide to help you navigate the vast terrain of sleep hygiene. For a concise overview of how better sleep hygiene can help you combat EDS, we’ve included the most pertinent recommendations below:

  • Be consistent: Go to bed and rise at the same time every day, even on the weekends, according to your circadian rhythm.
  • Step into the light: Sunlight is the most powerful circadian cue to spark wakefulness and banish drowsiness.
  • Move your body: During sleep, your core body temperature is at its lowest. As such, morning exercise is another helpful circadian cue to raise your body heat and up your wakefulness.
  • Avoid sleep-barring substances before bedtime: Caffeine remains in your system for up to 10 hours. You don’t have to avoid caffeine altogether, but you should begin to limit caffeinated beverages in the afternoon. You should also abstain from alcohol and nicotine at least 3-4 hours before bedtime to encourage healthy, natural sleep. RISE can tell you exactly when to limit these things based on your unique chronobiology and send you reminders. Go to the Energy tab in the app and add the “Limit Caffeine” and “Avoid Late Alcohol” reminders to your Energy Schedule.
  • Do an evening wind-down: Unplugging and slowing down helps prepare your mind and body for slumber. Take a hot shower, meditate, or read a book.
  • Reserve your bed for sleep and little else: Form a healthy association between your bed and sleep by only using it for slumber-related activities.

For the most part, bettering your sleep hygiene is conditional on slumber-promoting behaviors from day to night. Yet, many of us have difficulty sticking with new habits, no matter how well-intentioned they are.

That’s why RISE, the only sleep app based on the Two Laws of Sleep, comes with sleep hygiene recommendations personalized to your unique biology. Below, we give you a few sneak peeks into why RISE is the perfect ally to wrangle sleep deprivation and tackle EDS:

  • The “Sleep” tab shows your running sleep debt over the past 14 days. This gives you an idea of how consistent you’ve been in meeting your sleep need recently. There’s also a specific section to record your naps, which further minimizes sleep debt.
  • The "Energy" tab shows your circadian rhythm as a rolling graph of energy peaks and dips. Turning on the in-app notifications for the “Peaks and Dips” habit will send you reminders tailored to your biological rhythm. This way, you won’t be caught off guard when you feel the need to recharge during your afternoon dip.
  • The “Energy” tab also has other helpful reminders for improving your sleep hygiene. For example, the “Evening routine” habit lets you customize your evening wind-down routine with in-app notifications based on your personal sleep and wake times.

Rule Out Underlying Medical Conditions

A doctor smiles while holding a tablet

If you’ve tried improving your sleep hygiene or are getting enough sleep every night but still experience chronic drowsiness, it’s time to consult a  health care professional.

As mentioned earlier, EDS is closely entangled with myriad health problems. To identify the underlying cause(s) of your daytime drowsiness, a primary care doctor will review your medical history and conduct a detailed examination. Depending on which health problem is at fault, your doctor may refer you to other health care professionals — say, a sleep specialist in the case of sleep disorders.

Treatment options will vary according to the underlying medical condition. For example, sleep specialists usually recommend cognitive behavioral therapy for insomnia (CBTI). While wakefulness-promoting medications, such as modafinil and pitolisant, tackle sleep disorders like narcolepsy. If you're plagued with sleep apnea, you may be treated with a continuous positive airway pressure (CPAP) machine — it delivers a steady oxygen supply into your nose and mouth to ensure normal breathing during sleep.

The bulk of EDS treatments commonly combine pharmacologic interventions with sleep hygiene practices to resolve extreme drowsiness in a more sustainable manner. In other words, notwithstanding medical conditions, almost everyone can benefit from better sleep hygiene.

Stop EDS in Its Tracks for a Better Quality of Life 

EDS isn’t just an everyday inconvenience that saps your energy levels; it’s disadvantageous to your productivity, performance, emotions, mental welfare, and social relationships; essentially, everything that matters.

Understanding the causes of excessive daytime sleepiness is the first step to feeling and functioning better throughout the day. Follow up with mindful improvements to your sleep hygiene using the Two Laws of Sleep (sleep debt and circadian rhythm). If you still don’t see much improvement, you may need medical intervention to uncover hidden health problems and formulate an effective treatment plan. 

That said, in most cases, good sleep hygiene makes for a powerful defense against extreme drowsiness. That’s why we recommend getting the RISE app to make healthy wake and sleep habits the foundation of your battle plan against EDS.


About Our Editorial Team

Reviewed by
Jeff Kahn, M.S., Rise Science Co-Founder
Our Editorial Standards
We bring sleep research out of the lab and into your life. Every post begins with peer-reviewed studies — not third-party sources — to make sure we only share advice that can be defended to a room full of sleep scientists.
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Updated Regularly
We regularly update our articles to explain the latest research and shifts in scientific consensus in a simple and actionable way.

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Rise is the only app that unlocks the real-world benefits of better sleep.

Instead of just promising a better night, we use 100 years of sleep science to help you pay down sleep debt and take advantage of your circadian rhythm to be your best.

Over the past decade, we've helped professional athletes, startups, and Fortune 500s improve their sleep to measurably win more in the real-world scenarios that matter most.

Rise Science is backed by True Ventures, Freestyle Capital, and High Alpha; investors behind category winners Fitbit, Peloton, and Salesforce Marketing Cloud.

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