Excessive daytime sleepiness (EDS) is not the same as feeling tired all the time. Instead, it’s a persistent urge to sleep during typical waking hours that can be linked to a number of underlying causes, including sleep disorders, medical conditions, lifestyle factors, and medications.

It’s natural to feel tired once in a while. Life can be stressful. Sleep isn’t always quality. And sometimes, it’s just “one of those days.” Experiencing excessive daytime sleepiness, or EDS, however, is much more than just feeling fatigued.

EDS is part of a broader type of sleep dysregulation called hypersomnia (also known as hypersomnolence). Hypersomnia includes EDS, a persistent, overwhelming urge to sleep during your normal waking hours, as well as prolonged nighttime sleeping, or sleeping beyond what’s typical or necessary for your age and overall health.

You can experience EDS, prolonged nighttime sleeping, or both with hypersomnia, but living with EDS doesn’t necessarily mean you’ll experience extended overnight slumber, too.

For many people, EDS is a symptom of an underlying condition and not a stand-alone diagnosis. Your doctor can help you determine the cause of EDS so it can be treated at its source.

Only your doctor can diagnose the underlying cause of EDS, but becoming familiar with conditions that can lead to this overwhelming urge to sleep may help uncover clues that inform your diagnosis.

Central disorders of hypersomnolence

Central disorders of hypersomnolence are a group of central nervous system (CNS) disorders that feature EDS and/or prolonged nighttime sleep. Conditions that fall within this group include:

  • narcolepsy type 1
  • narcolepsy type 2
  • idiopathic hypersomnia
  • Kleine-Levin syndrome

Although the disease pathways related to each of these conditions vary, dysfunction in the CNS (the brain and spinal cord) affects parts of the brain responsible for sleep regulation, causing EDS, prolonged nighttime sleeping, or both.

Sleep deprivation

Sleep deprivation is a cumulative sleep deficit that develops when you don’t get enough sleep over a long period of time. Not meeting your sleep needs impairs the body’s ability to recover and restore, resulting in a wide range of physical and psychological symptoms.

EDS is a common symptom of sleep deprivation. Your body needs to sleep, and if you’re functioning at a deficit, you may experience overwhelming sleep urges during the day. According to the National Heart, Lung, and Blood Institute, as many as 40% of adults report falling asleep without meaning to at least once a month.

Sleep apnea

Sleep apnea is a disruption in your ability to breathe while asleep. Obstructive sleep apnea (OSA) occurs when your upper airway collapses or narrows during sleep and interrupts your breathing. Central sleep apnea (CSA) is the result of miscommunication between your brain and your respiratory muscles.

Breathing disruptions in sleep apnea can jolt you out of sleep, even if you aren’t aware that it’s happening, causing sleep fragmentation and interrupting restorative sleep stages.

A research review from 2021 notes as many as 58% of people living with untreated OSA experience EDS, and even with treatment, as many as 22% continue to report it as a persistent symptom.

Central disorders of hypersomnolence aren’t the only conditions that affect your nervous system and sleep function. Other neurological conditions can cause secondary hypersomnia as they impact neurological pathways essential for sleep, causing EDS.

Examples of neurological conditions that may cause EDS include:

  • brain tumor or injury
  • Parkinson’s disease
  • multiple sclerosis (MS)
  • Alzheimer’s disease and other dementias

Restless leg syndrome

Restless leg syndrome (RLS), also known as Willis-Ekbom disease, is a movement disorder characterized by irresistible urges to move your legs while awake.

Although some research suggests RLS has neurological underpinnings, its exact pathology isn’t clear. Leg movements in sleep are involuntary and are called periodic limb movement disorder (PLMD), which is another common sleep disorder.

Like other medical conditions that can disrupt slumber, RLS may cause EDS by preventing people from falling asleep in the first place due to the irritating symptoms.


Low energy and sleep disturbances (hypersomnia or insomnia) are included in the Diagnostic and Statistical Manual of Mental Disorders, 5th edition, text revision (DSM-5-TR)’s criteria for major depressive disorder (MDD).

Why MDD impacts sleep is not fully understood, but imbalances in brain chemicals and sleep disturbance from other physical and psychological symptoms may play a role. An analysis from 2019 found as many as 50.8% of people included in the sample population reported EDS with MDD.

Chronic fatigue syndrome

Chronic fatigue syndrome (CFS) is also known as myalgic encephalomyelitis. It’s a multisystem disease that presents with extreme fatigue that worsens after activity.

For some people, CFS may also be accompanied by sleep disorders and EDS, but EDS is not a core symptom of CFS.


When you don’t have enough red blood cells (RBCs) or hemoglobin in your bloodstream that’s a condition called anemia.

RBCs and the protein they contain called hemoglobin are essential for transporting oxygen throughout your body. If you can’t supply your cells with enough oxygen, your energy levels drop. If they drop low enough, you may feel the need to lapse into sleep.

According to a cross-sectional study from 2022 looking at anemia in older adults, 29.6% of those living with anemia reported EDS, compared to 18.6% of those without anemia reporting EDS.

Excessive daytime sleepiness can be a side effect of many medications, such as:

  • antidepressants
  • anxiety medications
  • antihistamines
  • blood pressure medications
  • antipsychotics
  • prescription pain medications
  • antiepileptic drugs

If you notice EDS while taking medication, speaking with your doctor can help determine if what you’re experiencing is a side effect.

Sometimes EDS is simply caused by chronic insufficient sleep. Even if you aren’t meeting the criteria of sleep deprivation, missing out on quality sleep often enough can trigger excessive sleepiness during the day.

Lifestyle factors that can contribute to insufficient sleep leading to EDS include:

  • poor sleep hygiene (sleep routines, habits, and environment)
  • sedentary lifestyle
  • shift work
  • substance use
  • chronic stress
  • poor diet and dehydration

Treating the underlying cause of EDS is the first step toward reducing this symptom, but you can also take proactive steps to improve your sleep at night and boost alertness during the day.

Strategies to reduce EDS include:

  • keeping a consistent sleep-wake schedule
  • improving your sleep environment by making your room cool, dark, and quiet
  • skipping stimulants like caffeine in the evening, cutting them off before mid-afternoon
  • finding alternatives for sedating medications
  • avoiding sleeping pills that can cause sleepiness to linger into the day
  • avoiding high-carbohydrate meals mid-day
  • working in brightly lit spaces
  • taking a short nap, early in the day to avoid impacting nighttime sleep

EDS is characterized by overwhelming, persistent urges to sleep during typical waking hours. Along with prolonged nighttime sleep, EDS is a form of sleep disturbance known as hypersomnia.

EDS can have many different underlying causes. Physical and psychological conditions that interrupt sleep or affect sleep cycles, as well as lifestyle factors that contribute to chronic sleep insufficiency, are all possibilities.

Speaking with your doctor about EDS can help determine which underlying factors may be involved.