Excessive Daytime Sleepiness

This is a fact sheet about Excessive Daytime Sleepiness. There are many things that can cause excessive sleepiness in the day such as your lifestyle, physical & mental health and your sleep habits.

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January 12, 2024
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min read


Things you should know:

  • There are many possible reasons why you may feel sleep more often than you think you should.
  • Solving the problem of your sleepiness will often come from working on it together with your GP.
  • Don't ignore sleepiness if you drive a car or operate heavy machinery.

What is excessive daytime sleepiness?

Being sleepy is the desire or necessity to fall asleep.  It may or may not include feelings of fatigue and/or ‘being tired’.

Everyone has days when they feel sleepier or tired than normal.  Sometimes you know why this is the case. Often, it's to do with a busy lifestyle or too many late nights.  But some people feel sleepy day in and day out and cannot work out why.  In fact, they may fall asleep at times and places where they really should stay awake, such as on the train home or during a conversation.  Obviously, it is unsafe to feel sleepy while driving. This often alerts us to a problem.

What may cause it?

This is often the hard part. You will need to try to work this out.  Often this will involve your GP too. Usually, the cause of your sleepiness can be worked out just by talking to a health professional.

Some possible reasons for being sleepy during the day are:

  • Your lifestyle. Are you burning the candle at both ends? Do you wish you could spend more time in bed? Are you trying to do too much and not looking after your need for sleep?  Enough sleep is important for good health – make it more of apriority.  Remember that if you have enough sleep, you will be able to do a lot more during the day.
  • Poor sleep habits. Some people spend enough time in bed but are unable to have good quality sleep.  This can make them sleepy during the day.  See insomnia and good sleep habits.  You might sleep well once you have fallen asleep but find it hard to go to sleep until late at night. This could be due to exercise, coffee or cigarettes in the evening, too much napping during the day or Delayed Sleep-Wake Phase Syndrome (DSWPS).  See also Common Causes of Inadequate Sleep.
  • Your physical health. There are many reasons why you may feel tired, fatigued or sleepy. They are not always due to sleep disorders. The cause could be another problem with your physical health. Talk to your GP about a thorough check up. There are a lot of things that could be causing it e.g., heart problems, diabetes, lung disease, iron levels or an underactive thyroid.  Arthritis or other pain may make it difficult to sleep well at night. Some people have to get up several times at night to go to the toilet, which interrupts their sleep. All of these and many other health problems may be the cause of being sleepy during the day.
  • Your mental health. If you are anxious, you may find it hard to get to sleep and/or stay asleep. Depression can also have a big effect on your sleep.  Your GP can talk about treatment options. Part of this could be a referral to a psychologist for help.
  • Shift work. Is changing shifts confusing your body clock? It is best to be consistent with when you go to bed. This can be hard if you work shifts. How well you sleep and how much sleep you have can both suffer with shiftwork. See our information on shift work and/or the body clock.
  • Your breathing at night. Some people do not breathe normally at night. Often, they are not aware of it, but their bed partner may notice that they move around the bed a lot at night, snore or even stop breathing for short periods of time. This will make their sleep lighter. It will be hard to stay asleep for a longtime as well. These symptoms suggest Obstructive Sleep Apnoea (OSA). If it seems like this could be the case, be sure to ask your doctor about it. It is important to treat sleep apnoea and there are very effective treatments available, e.g., CPAP, oral appliances.
  • A sleep or neurological disorder. There are some sleep disorders with no link to breathing problems that can interfere with your nighttime sleep. This will make you sleepy in the daytime (see Common Sleep Disorders).  The key neurological problem that makes you sleepy during the day is narcolepsy.
  • The fatigue of Chronic Fatigue Syndrome is not the same as sleepiness. See Chronic Fatigue Syndrome and Sleep for more information.

Where and when should you seek help?

If you have been struggling with feeling sleepy and cannot explain it, then you should talk to a health professional. Together, you can try to work out why this may be. Tests may be a part of this. If it seems to be a sleep disorder, you may be referred to a sleep specialist.

How do they work out how sleepy you are?

Your GP and sleep specialist will ask you questions about your sleep patterns, your sleep habits and the things that you are finding it difficult to do during the day. For example, if you are falling asleep when sitting in a boring meeting, it is less likely to be a major sleep problem than if you are falling asleep during a meal. A sleep specialist may ask you to fill out a list of questions called the Epworth Sleepiness Scale, which is a screening tool. They may then decide to refer you for an overnight sleep study.  This will show if there is any problem with your night sleep.  In some cases, they may ask that you stay there for the next day so that you can also have a Multiple Sleep Latency Test. The page on narcolepsy discusses this more.

Where can I find out more?


Download a PDF of this Fact Sheet

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