What Is Excessive Daytime Sleepiness, and What Causes It?

Macgill Davis

In today’s fast-paced culture, it’s not unusual to feel tired. But sometimes, it’s more than just tiredness. Excessive daytime sleepiness (EDS for short) can be a symptom of underlying medical and sleep disorders you shouldn’t ignore.

In this article, we’ll describe what EDS looks and feels like, and list its most common underlying causes. At the end, we’ll give you ideas for how you could reduce excessive daytime sleepiness in your life.

First, let’s understand how to tell EDS from an occasional energy slump.

How to Tell If You Suffer From EDS

A 2019 study estimated that EDS is experienced by 10-20% of the population. This means that up to one-fifth of society feels sleepy to the point that it disrupts their plans, productivity, and quality of life.

You may be asking yourself whether the sleepiness you feel can be classed as EDS. An occasional afternoon slump or difficulty getting out of bed happens to everyone. But there are warning signs that your excessive sleepiness may signal an underlying health condition or sleeping disorder. Some of them include:

  • Trouble staying alert
  • Feeling more irritable than usual
  • Difficulty concentrating
  • Slower reaction times
  • Brain fog
  • Worsening memory

Usually, it’s the prevalence of your sleepiness that determines whether or not it might be a serious problem. The Sleep Foundation suggests that when symptoms continue for three months and beyond, that’s when you’re dealing with EDS.

To assess the degree of your sleepiness, you could use the Epworth sleepiness scale. It’s a self-administered questionnaire to determine how prone you are to falling asleep during particular activities throughout the day. Based on the score, you can decide whether this is a problem you may want to take to the doctor.

4 Common Causes of Excessive Daytime Sleepiness

Most causes for excessive daytime sleepiness are connected to sleep problems during nighttime. If your body doesn’t rest at night, it tries to compensate for it during the day. However, there’s often more to it than just going to bed late.

Sometimes, the reason isn’t quite as obvious. There are many potential causes of excessive daytime sleepiness. We list the most common ones below.

1. Sleep Deprivation

Among the most common causes of EDS is sleep deprivation. This means sleeping too short, or missing out on sleep when your body would most benefit from it.

According to the National Sleep Foundation, our circadian rhythms dictate that some hours are more conducive to good sleep than others. If your sleep falls mainly outside of those hours, you may suffer from sleep deprivation — even if you sleep long enough.

One factor that heavily influences this is shift work. People who work at night and sleep during the day usually go against their circadian rhythms. This increases tiredness and contributes to daytime sleepiness.

Even without shift work, you may be missing out on sleep if you’re overworked. Working all day along and into the night is a common cause of sleep deprivation.

2. Bad Sleep Habits

Excessive daytime sleepiness: person yawning while at work

Bad sleep habits are often responsible for reducing your sleep quality. This means that even if you spend the recommended 7-9 hours in bed, it may not be as deep and restful as it should.

Some bad habits include: 

All these habits have been proven to lower the quality of your nighttime sleep, which in turn causes sleepiness and drowsiness during the day.

3. Side Effects of Medication and Others Substances

Certain substances can increase feelings of tiredness and sleepiness. Some of them do that through disrupting nighttime sleep. Alcohol has been shown to decrease sleep quality, even though it’s considered a sedative. Other substances, like caffeine, disrupt your sleep due to their stimulating nature.

Some medication doesn’t directly impact sleep quality but can still impact your energy levels throughout the day. It’s common for certain antidepressants — especially in the first weeks of treatment — to increase feelings of sleepiness.

4. Medical Conditions

The underlying cause of EDS can be a medical condition. Some of them are sleep disorders that cause micro-awakenings throughout the night. They prevent you from going into the REM sleep phase, which is essential for consolidating memories, brain development, and emotional processing.

Here are some examples of disorders that can cause fragmented sleep: 

  • Obstructive sleep apnea: This sleep disorder causes disrupted breathing patterns during the night, which often includes prolonged pauses in breathing. This may mean your brain needs to reactivate breathing every now and then, and hence can’t go into deep sleep.
  • Restless legs syndrome: Characterized by uncomfortable sensations in your legs, restless legs syndrome is a common disruptor of good sleep. It causes you to feel an urge to move your legs, which keeps you from falling asleep.
  • Periodic limb movement: This is quite a rare sleeping disorder. It’s characterized by periodic, repetitive, involuntary movements of your limbs at night. This may be hard to spot yourself, as the movements happen while you’re asleep. It’s often the sleep partner who first notices the symptoms.

Other sleep disorders fiddle with your ability to be awake during the day despite getting good sleep at night. These are related to your brain’s neurology, circadian rhythms, and regulation of hormones that support wakefulness:

  • Narcolepsy: The main symptom of narcolepsy is a decreased ability to regulate your sleep-wake cycles. This can include prolonged drowsiness, difficulty staying awake, and unexpected sleep attacks. Other narcolepsy symptoms are cataplexy (sudden loss of muscle strength throughout the day) and sometimes also sleep paralysis.
  • Idiopathic hypersomnia: The disorder manifests when you chronically feel sleepy despite having slept well and long at night. It may include difficulty waking up, even from a nap. What’s more, those naps don’t leave you feeling refreshed.
  • Circadian rhythm disorders: These occur when your times of sleepiness and alertness fall out of alignment with your circadian rhythms. This can happen due to jet lag, insufficient light exposure during the day, excessive light exposure at night, and a number of other reasons.

The Negative Consequences of Poor Sleep

Tired woman touching her forehead while holding her glasses

Ongoing excessive daytime sleepiness and lack of energy can be a serious bummer. They may ruin your plans, undermine your personal productivity, and make it hard to enjoy life in general.

If you suffer from EDS, your work performance will almost certainly suffer, too. When your brain doesn’t get enough sleep, it can’t function at its full capacity. It acts like a computer that’s never turned off and doesn’t have a chance to reload the system and install relevant updates. 

The ways in which this may manifest in your workday include:

  • Cognitive impairment, such as difficulty focusing on tasks
  • Difficulty remembering things
  • Higher risk of accidents (e.g., falling asleep while driving or operating a machine)
  • Lower productivity
  • Deterioration of your work relationships
  • Increased irritability
  • Struggles with decision-making
  • Slow reaction times

Sleep deficit can also be a serious risk factor for long-term health problems. Scientists found links between not sleeping enough and the weakening of your immune system, neurological disorders, higher blood pressure, risk of heart disease, diabetes, obesity, and other conditions. In some instances, poor sleep and daytime sleepiness may be factors for developing Parkinson’s disease.

It’s worth looking at your sleep and energy levels before your work and health is in serious trouble. So, what are the actions you can take?

10 Ideas to Improve Your Sleep and Energy Levels

Let’s start this with a disclaimer. Because there are so many possible reasons for excessive daytime sleepiness, we can’t give you a panacea for fighting it. If you feel like EDS is heavily impacting your health and/or wellbeing, you should probably see a doctor about this.

A sleep specialist will be able to prescribe a relevant treatment option, depending on the underlying cause of your sleep problems. They’re likely to do a multiple sleep latency test to determine how serious your case is and whether you may have an underlying medical condition.

Some treatments for sleep disorders include cognitive behavioral therapy, timed short naps, or positive airway pressure (specifically used to treat obstructive sleep apnea). There is also a range of sleep medicine available, such as modafinil, armodafinil, melatonin, and others.

However, it may be that you can improve your sleep by changing your habits and routines around it. Sleep studies show that sleep hygiene is closely related with the quality of your sleep

Here are a few actionable ideas for how to improve your sleep hygiene.

  1. Make your bedroom quiet, cool, and dark. These are the three elements of your sleep environment that help you sleep better.
  2. Allow enough time for sleep. Most adults need 7-9 hours of sleep to function at their best.
  3. Try going to bed and waking up at roughly the same time each day. It will help your body settle into a rhythm and make falling asleep and waking up easier.
  4. Avoid stimulants — such as coffee, alcohol, and nicotine — in the afternoon and evening. Try to reduce the consumption of those substances in general.
  5. Use your bed only for sleep. This helps your brain know that this is a place where you relax.
  6. Establish a winding-down routine in the evening. This will calm your nervous system and transition your body into sleeping mode.
  7. Make sure you get enough exercise during the day. More oxygen in your body, as well as getting physically tired, will help you sleep healthily.
  8. Expose yourself to natural light during the day, and avoid screen exposure in the evenings. Your body will be more in tune with its circadian rhythms and know when it’s time to sleep and wake.
  9. Eat your last meal no later than three hours before going to bed. This should allow your body to digest most of the food before you fall asleep.
  10. Have something to look forward to in the morning. This will make waking up easier, and you’ll be more likely to stick to your sleeping schedule.

Eliminate Daytime Sleepiness By Tracking It First

If you’re not sure how much daytime sleepiness is in the way of achieving your goals, we have good news. You can learn that by tracking how you spend your days and how much time you waste due to being overly sleepy.

With an intelligent time tracker like Rize, you can get an overview of the time spent working, resting, as well as the time when you got distracted. This can help you determine the impact your daytime sleepiness has on your performance.

Try Rize now, for 14 days, free of charge. No credit card is required to sign up.