What is insomnia?

Insomnia means having difficulty getting to sleep or staying asleep, or waking up still feeling tired (fatigued). Many people affected by cancer have trouble sleeping, for lots of different reasons.

Insomnia includes having some, or all, of the following symptoms:

  • Difficulty getting to sleep.
  • Waking up during the night or waking too early.
  • Difficulty sleeping despite good conditions for sleep – such as having a comfortable bed in a quiet, darkened room.
  • Things you do in the daytime are affected by lack of sleep – for example, problems concentrating at work, falling asleep during the day or feeling low in mood.

Other types of sleep problems

If you only sleep for a few hours every night, you may be worried that you have insomnia. But you may need less sleep if you are doing less. If you do not feel tired during the day, try not to worry about not sleeping much at night.

Some people sleep less at night but may have a short afternoon nap, which can be refreshing. Other people, such as night shift workers or parents with small children, might not get enough sleep but not have insomnia. This generally means that they would be able to sleep quite well if they had the right conditions.

It is normal to wake up briefly during the night at the end of each sleep cycle. A sleep cycle lasts about 90 minutes. As we get older, we sleep less deeply and wake up more during the night. But if you wake up a lot, take a long time to get back to sleep and wake in the morning tired, you may need help to improve your sleep quality.

Losing one night of sleep will not have any effect other than making you feel tired the next day. But long periods of sleeplessness can lead to anxiety, depression, concentration problems or difficulty making decisions.

If you are worried that disturbed sleep is affecting how you function during the day, talk to your doctor or specialist nurse.

Causes of insomnia

Different things can affect sleep and cause insomnia. Some are things that can affect anyone, such as anxiety or worries. Others are more common in people affected by cancer.

Things that may affect your sleep include:

  • your bedroom being too hot, cold, too light or noisy
  • having an uncomfortable bed
  • having a poor sleep routine, or sleeping too much during the day
  • you and your partner having different sleep routines
  • smoking, or drinking alcohol or caffeine
  • not doing enough physical activity during the day
  • taking medicines that affect sleep, such as steroids steroids
  • anxiety or emotional distress
  • physical problems, such as pain, discomfort or feeling unwell.

Things you can do to improve sleep

Having good sleep habits can help improve sleep. This includes having a regular bedtime routine.

Routines can tell your brain that it is time to sleep. For example, you could:

  • have a caffeine-free hot drink
  • take a warm bath
  • read in bed for a while.

We have included some suggestions below of other things that could help you sleep better.

  • Sleep for the right amount of time

    Spending too much time in bed is likely to affect the quality of your sleep. Try to sleep for long enough to feel refreshed the next day, without oversleeping. Most adults need between 7 and 8 hours of sleep. But this can vary, so work out what is best for you.

  • Try to do more physical activity

    Doing more physical activity during the day can improve the quality of your sleep. It will also help to build up your strength. This may be difficult if you have recently had treatment and are struggling to cope with low energy levels or side effects. But even something small will help, such as regular, short walks or gentle gardening. Remember that doing exercise just before bed might affect your sleep.

  • Go to bed and wake up at the same time each day

    This is not always possible, but it can help you get into a good sleep routine.

  • Keep your bedroom for sleeping

    If you wake up during the night and find it difficult to go back to sleep, go to another room in your home until you feel ready to sleep again. If you need to sleep during the day, go to your bedroom and sleep.

  • Make your bedroom a relaxing place

    Try to keep your bedroom dark, quiet and comfortable. Having too much light in your bedroom can make it hard to fall asleep. It can affect your body’s sleep clock (also called the circadian rhythm). Your sleep clock roughly follows a 24-hour cycle that is regulated by exposure to light during the day and reduced light at night. This helps you sleep during the night and be awake during the day. Dark curtains or a blind can help to reduce the amount of light in your bedroom. If your bedroom is noisy, using ear plugs may help.

  • Keep your bedroom a constant temperature

    If your room is either very warm or very cold, this may affect your sleep. The room temperature should be comfortable.

  • Avoid watching TV or using a computer before bed

    Try to avoid watching TV or using a mobile phone, tablet or computer before going to bed. It may make your brain more active, which can delay sleep. The screens on these devices have a blue light that can make it harder to fall, and stay, asleep.

  • Avoid going to bed hungry

    Being hungry can disturb your sleep. Try having a light bedtime snack, warm milk or a hot drink before going to bed. But avoid large meals and a lot of fluids. Also try to avoid food and drinks that contain stimulants, such as caffeine, or lots of sugar, such as coffee, tea, cola or chocolate. It is a good idea to avoid smoking cigarettes in the late evening too.

  • Limit how much alcohol you drink before bedtime

    While alcohol can help you to fall asleep more quickly, your sleep is usually interrupted. It may also mean you wake up with a dry mouth and an unpleasant taste. Try to limit how much alcohol you have near bedtime. Even a small amount of alcohol can sometimes make insomnia worse.

  • Understand how naps affect you

    You might find that short, daytime naps help you sleep better at night. Or you may sleep less well after a nap. A short nap after lunch is likely to be better than one during the evening. Find out what suits you best.

  • Try mental exercises

    These could also help you sleep, as they focus your brain away from any worries. Here are a few mental exercises you could try: 

    • Try to remember the lines of a song or poem.
    • Make alphabetical lists, for example of names or countries.
    • Try to remember a favourite experience in detail.


  • Take a break from trying to get to sleep

    Get out of bed and try to empty your mind. You could read or do some relaxation techniques, and then try going back to bed after 10 minutes. You can repeat this if you are still unable to sleep. It may help to avoid watching TV or using computers, phones or anything with a bright light when you are up. But some people find listening to a familiar story or watching a relaxing programme on TV can help them sleep. You could set a timer to switch off the device after a short period of time.

Worry and anxiety as a cause of insomnia

Being diagnosed with cancer can cause feelings of worry and anxiety. These can stop you being able to sleep. Many people find they stay awake, going over the same thing in their mind. It may help to try some of the tips below.

Write down your concerns

If you wake at night and are worrying about things, write them down. There might be nothing you can do about them straight away. But if you write them down, you can then work through them during the day. You could ask for support from a family member or friend.

Talk to someone

You may find that talking to someone about your fears and worries helps you cope. Talking can be a relief, and you may find that you sleep better afterwards.

Try talking to a close friend or family member. Or you might prefer to talk to someone outside of your family. You may find it helps to share your worries with an online community, such as Macmillan’s Online Community. The emotional support forum is a place to talk with others who understand what you are going through. Or you may want to talk to a counsellor. Your GP may be able to refer you to a local counsellor, or you could contact Samaritans by calling their 24-hour confidential helpline on 116 123.

Macmillan offers free one-on-one counselling with a qualified Bupa therapist, who has been trained in supporting people living with cancer. To access this service, call the Macmillan Support Line on 0808 808 00 00 and ask about the Bupa service.

Try relaxation techniques

Simple breathing and relaxation exercises may be very useful in reducing anxiety and stress. They can also reduce muscle tension. Many people with cancer, and their family members, find that these simple methods relax them.

Almost anyone can learn relaxation techniques. You can learn them at home using CDs or podcasts, or you may prefer to join a group. You need to do self-help exercises regularly for them to work well. It may be easier to stay motivated by going to group classes.

You may also benefit from resources such as app-based mindfulness and CBT programmes.

  • Sleepio offers a 6-week sleep improvement programme to help you sleep better if you have increased worries. Sign up for free to Sleepio today.  

Lying flat can be uncomfortable for people who are breathless or in pain. But many relaxation exercises can be done sitting up or using pillows for support. We have a free audiobook which can help you learn ways to manage breathlessness.

The following organisations also offer relaxation sessions, which are free to download or buy as a CD:

Some hospitals and support groups offer relaxation sessions. You can ask if they are provided at your hospital. You may also be able to get relaxation apps on your phone or tablet.

Medicines that can cause insomnia

Many medicines for cancer and some other illnesses can disturb sleep. Not everyone who takes these drugs will have problems sleeping, as medicines affect people in different ways. Talk to your doctor, specialist nurse or pharmacist about whether your medicines may be affecting your sleep. They may be able to give you advice. For example, they may suggest taking medicines that make you very alert, such as steroids, in the morning. 

Some medicines stop you from sleeping because of other side effects. Hormonal therapies for breast and prostate cancer can cause hot flushes and sweats. These may keep you awake. Your doctor, specialist nurse or pharmacist may be able to offer some help and advice with these.

Some medicines can cause drowsiness. It may be helpful to take these at bedtime. But it is important to check with a member of your healthcare team before making any changes to your medicines.

Treating insomnia with sleeping tablets

If not being able to sleep becomes difficult and is affecting your daily life, it can sometimes help to take a short course of sleeping tablets. Generally, sleeping tablets are only prescribed for 1 to 2 weeks, because they can have side effects.

If you think this may help, talk about it with your doctor. They can advise whether tablets are suitable for you.

There are different types of sleeping tablet that work in different ways.

  • Benzodiazepines

    These work by increasing the effect of a substance in the brain called gamma-aminobutyric acid (GABA). GABA is a chemical messenger that can make you feel calm and drowsy. Some benzodiazepines are short-acting and can help you get to sleep. Others are long-acting and can help you stay asleep. Examples of benzodiazepines include: 

    • temazepam
    • diazepam
    • lorazepam.
  • Non-benzodiazepines

    These work in a different way from benzodiazepines, but they also help you sleep by increasing the effect of GABA in the brain. They are sometimes called Z-drugs. Examples of non-benzodiazepines include: 

    • zolpidem (Stilnoct®)
    • zopiclone (Zimovane®).

Side effects of sleeping tablets

Most people have some side effects of sleeping tablets when they wake up the next day. The side effects are often described as being like how people feel after drinking too much alcohol (a hangover). They usually go away quite quickly.

Some of the most common side effects of sleeping tablets are:

  • being clumsy or having poor co-ordination
  • feeling light-headed, dizzy or still sleepy
  • difficulty concentrating or thinking clearly.

Sleeping tablets may increase the risk of having a fall if you get up during the night.

You should not drive if you feel sleepy, dizzy or unable to concentrate.

Tolerance and dependence on sleeping tablets

Doctors may be cautious when prescribing sleeping tablets. This is because sleeping tablets can cause problems with tolerance and dependence.

Drug tolerance means that as you continue to take a drug, it begins to feel as though it is no longer helping. You may need a higher dose to get the same effect. In time, the higher dose will also begin to feel as though it has no effect, while side effects may get worse.

Drug dependence means that you may get withdrawal symptoms if the drug is suddenly stopped. Withdrawal symptoms can include:

  • feeling anxious
  • feeling restless
  • difficulty sleeping.

For some people, withdrawal can feel similar to the symptoms of insomnia.

Tolerance and dependence may sound worrying. But most people do not have these problems if they are only taking sleeping tablets for a short period of time. Talk to your doctor if you are worried about tolerance or dependence. Your doctor may check how you are feeling while taking sleeping tablets.


Melatonin (Circadin®) is a natural hormone that is available as a tablet. It is used to treat insomnia as well as some other conditions. In the UK, melatonin is only licensed to be given as a short-term treatment for insomnia to people over the age of 55. So far, research has shown that melatonin causes fewer problems with tolerance and dependence. But for most people, it only reduces the time it takes to get to sleep by about 30 minutes.

Over-the-counter medicines

Sleeping tablets do not always need to be prescribed by a doctor. Over-the-counter sleeping tablets can be useful in the short term. But many people find if they take them for long periods, they develop a tolerance to these drugs.

Over-the-counter sleeping tablets often contain anti-allergy medication (antihistamine) and are not suitable for everyone. They may not be recommended if you are taking some other types of medicine. If you are thinking of trying an over-the-counter medicine, speak to your doctor, specialist nurse or pharmacist first.

Treating insomnia with behavioural therapies

Behavioural therapies help to change the way you think, feel and behave when it comes to sleeping. There are three main types of behavioural therapy that can be used for improving sleep.

Sleep restriction

For some people, spending too much time in bed means they wake up too early. Sleep restriction aims to help you go to bed at certain times, usually later than you normally would. This helps you get regular amounts of good-quality sleep.

Stimulus control

People who regularly have difficulty sleeping can have a strong mental link between their bed and not sleeping. This therapy aims to break that link by only using the bed for sleeping. You should do other activities such as watching television, using a laptop or eating in a different room if possible. If you worry while lying in bed, this therapy recommends you go to another room and try to distract yourself until you feel tired. This aims to break the mental link between your bed and worrying.


Some people have trouble getting to sleep because their mind becomes active at bedtime. Mindfulness can help with this. Mindfulness is a way of focusing your thinking on the present moment and accepting how you are feeling. There are different mindfulness techniques available, including apps for your phone or tablet.

Cognitive behavioural therapy for insomnia (CBT-I)

Cognitive behavioural therapy (CBT) is done by a trained therapist. This type of therapy aims to change negative ways of thinking that may increase worries and anxiety. Reducing your anxiety may help you get more sleep.

Some of these therapies can be done by a GP with specialist training, or you may be referred to a clinical psychologist.

Cognitive behavioural therapy for insomnia (CBT-I) is a programme which combines:

  • sleep hygiene (having a regular bedtime routine)
  • sleep restriction (see above)
  • stimulus control (see above)
  • relaxation techniques (see above).

It also helps with negative thoughts about sleep. It can help you deal with worries about not having enough sleep and the effect this can have on your day-to-day routine.

CBT-I is available through some psychology services. The therapist may work with just one person, or with a group.

If you think some of these therapies could help you, speak to your GP.

About our information

  • References

    Below is a sample of the sources used in our difficulty sleeping information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk

    National Institute of Clinical Excellence (NICE). Insomnia. Clinical Knowledge Summaries. Last revised March 2021. Accessed January 2020. Available here: cks.nice.org.uk/topics/insomnia 

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Chief Medical Editor, Professor Tim Iveson, Consultant Medical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

Date reviewed

Reviewed: 01 November 2020
Next review: 01 November 2023

This content is currently being reviewed. New information will be coming soon.

Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

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