It’s common to feel sleepy or tired. In fact, around 1 in 2 adults report feeling more tired than they would expect. But how sleepy is too sleepy, and if you are feeling sleepy, what is causing it, and what can be done about it? 

Sleepiness vs tiredness

Although the terms ‘sleepiness’ and ‘tiredness’ are often used interchangeably, they mean different things and have other causes. Here are some key points to remember when differentiating them:

  • Sleepiness is an overwhelming need to sleep. Heavy eyelids, eyes that can’t stay open, finding yourself falling asleep even if you’re trying to concentrate on something else.
  • Tiredness is a sense of being exhausted. Having no energy left to do anymore. Needing to just stop and either lay down or rest. 

We experience each of these symptoms pretty commonly to varying degrees, but it is essential to recognise that tiredness won’t be fixed by sleep and vice versa, sleepiness won’t be cured by rest. 

A more detailed post on tiredness and fatigue is here.

Common causes of sleepiness

Although there are many different causes of sleepiness, it is helpful to break this down into different categories:

Not getting enough sleep

How much sleep do we needThe most common cause of sleepiness is consistently getting less sleep than needed. The American Academy of Sleep Medicine recommends that adults of working age should get at least 7 hours of sleep each night. (Read more: How much sleep do I need?) Everyone is different, so it can be hard to work out how much you need. But if you think of a period in your life when you felt well rested and reflect on how much sleep you averaged each night during that time, you will be able to get an idea of your sleep need. The other way of testing this, is allow yourself a little more time to sleep each night, for example 30 minutes, and see if this helps you feel less sleepy after a few weeks. 

Sleep is not at the right time for your body clock

Many people in this category are shift workers who are working the night shift or sleeping when their body clock expects to be awake. But it can also occur in people with health problems such as depression, ADHD or autism. This situation can be challenging to deal with. To minimise the impact of shift work aim for a work schedule that allows sufficient time for rest and recovery, and shifts that rotate gradually rather than rapidly rotating shifts. (Read more: Coping with shift work) There are also strategies to help better align your sleep, body clock and the day / night light cycle in this video on managing the circadian rhythm

Poor quality sleep

The two most common causes of this are obstructive sleep apnea and insomnia due to hyperarousal or chronic stress.

  • Snoring is very common, around 25% of the men population snore. Sleep apnea is less common than snoring but still common overall. Around 5% of men and 3% of women have bad enough sleep apnea that it is contributing to sleepiness that is having an impact on them throughout the day. 
  • Insomnia – trouble getting to sleep or staying asleep and feeling tired or sleepy through the day – is also common affecting around 1 in 6 adults. Even if you’re not having major trouble getting to sleep or staying asleep, hyper-arousal or chronic stress can impact sleep quality and result in sleepiness or tiredness through the day.

Other sleep disorders such as restless legs syndrome can also result in poor quality sleep. 


Despite getting enough, good quality sleep at the right time, do you still feel sleepy? Are you taking any prescriptions? Many medications, particularly those used to treat anxiety or depression, can cause sleepiness. If you feel uneasy with the effect of the drugs you are taking, it is best to review these with your doctor.

Medical and mental health disorders

Feeling sleepy is a common symptom of a range of medical and mental health disorders. People with chronic inflammatory disorders, recent infection or surgery, auto-immune disorders, heart failure and neurological conditions can be tired or sleepy as part of their condition. Sleepiness can also be a part of mental health problems including depression, anxiety, PTSD (and complex PTSD) and personality disorders, particularly borderline personality disorder

Central disorders of hypersomnolence

These are a specific group of sleep disorders characterized by persistent symptoms of sleepiness. These include narcolepsy and idiopathic hypersomnia. Fatigue syndromes such as ME/CFS, and Long-COVID can also have sleepiness as part of the disorder, but usually also have symptoms of tiredness and fatigue as well as post-exertional malaise (PEM).

What can I do about being sleepy?

First of all, ask yourself if you feel really sleepy or if your symptoms are more of tiredness or exhaustion. If you are tired, rest, managing stress, looking after your general health are necessary steps as the problem may not be with your sleep. If you are sleepy, then work through the list of possible contributing factors to your sleepiness (above) and consider which potential cause best fits your situation.

You may also address sleepiness by trying to get more sleep, especially if you haven’t been getting enough time for rest and are chronically sleep deprived. Try getting to bed a little earlier. Even 30 minutes earlier than your usual schedule can make a big difference as that amounts to 3.5 hours of extra sleep across the week. As best you can, keep a regular arising time that roughly coincides with when the sun comes up where you live. You may not have control over this, but the general principle of having a set time you get up each morning helps to synchronize your sleep and body clocks, improving both sleep and energy levels throughout the day.

What should I do if I need help?

A range of conditions can affect your sleep and result in symptoms of sleepiness. If you have tried to manage sleepiness yourself, but are still having trouble it is best to seek the help of your health professional. They can look at your overall health to look for factors contributing to sleepiness, and refer you on for specialist care if needed.

Related links and posts:

Need more information on how you can sleep better?

At Sleephub we understand the struggle people endure with sleeping problems which is why we have created a comprehensive FAQs page with information for those seeking information about sleep disorders and potential solutions. You can also check out our extensive resources and subscribe to our podcast.




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