What is a sleep diary and how can it help your health?

Amy Gallagher
Senior Sleep Physiologist at Cromwell Hospital
20 January 2022
Next review due January 2025

It’s common to have a few sleepless nights now and again. But sometimes, poor sleep can become a regular thing. This can take its toll on your physical and mental health. If you’re trying to improve your sleep, it can be hard to know where to begin. This is where keeping a sleep diary can help. By monitoring how you sleep, you can gain clues about what might be causing any issues.

Here, I explain the benefits of using a sleep diary, and how to get started with tracking your sleep.

An image showing a person and a dog asleep

What is a sleep diary?

Keeping a sleep diary involves jotting down details of things that may affect how well and how long you sleep. So, this could include information about your schedule, what you eat or drink, or how much exercise you do. All these factors can affect how well you sleep at night.

It also records whether you have trouble falling asleep in the first place or staying asleep. This can help you to get a good picture of your sleep habits and behaviours.

Why is a good night’s sleep important?

Good sleep is a key part of good health. Benefits include:

  • better heart health
  • the ability to concentrate better
  • a stronger immune system
  • better mental health


If you’re not sleeping well, it can affect your general health and wellbeing in many ways. You might feel more anxious than usual the following day, or struggle to complete daily tasks. In the long-term, poor sleep can have more serious effects on your health and wellbeing. Such as an increased risk of many chronic illnesses, including heart disease.

How can a sleep diary help?

Keeping a sleep diary can help you to work out how long you sleep for each night. You can then compare how much sleep you’re getting against the recommended seven to nine hours.

A sleep diary can also help you to recognise if your habits or routines are affecting the quality of your sleep. For example, perhaps you find it harder to fall asleep when you work late into the evening. Or maybe drinking a glass of wine after dinner causes you to wake up more during the night.

How to keep a sleep diary

You might like to record details of your sleep in a notebook or on your phone. It can help to use a template (PDF 2.1MB), which will prompt you to record the most important details about your sleep. You simply complete a short series of questions both morning and night.

What to record

While the contents of a sleep diary can vary, you might consider recording the following.

  • Any exercise you did within four hours of going to bed.
  • Any caffeinated drinks or high sugar foods you had within four hours of going to bed.
  • Whether you watched TV or spent time on your phone or tablet before bed.
  • If you had any daytime naps, and if so, how long they were.
  • How refreshed you feel in the morning, on a scale from 0 to 5.


Top tips for getting the most out of your sleep diary

To help you get the most out of your sleep diary, follow these tips.

  • Record both your daily habits (in the evening) and the quality of your sleep (in the morning). This can help you to make connections between an event such as drinking coffee, to an outcome, such as poorer sleep.
  • Keep your sleep diary every day for at least a week. This will give you more information about what’s going on and perhaps identify any patterns.
  • Set a reminder on your phone to help you to remember to complete your diary.
  • Leave your sleep diary by your bed so you remember to fill it out.


Using fitness trackers and apps to monitor your sleep

It can sometimes be difficult to accurately remember how long you stayed asleep for, as well as any disruptions during the night. For example, research suggests that if you have trouble sleeping, you may underestimate how long you actually sleep for. One way to help with this is to use a fitness tracker or health app.

Many newer fitness trackers also record the quality of your sleep. When worn at night, they can reveal:

  • how deeply you slept
  • the total number of hours you were asleep for
  • if you woke up during the night


You can then compare this data with your own observations. These trackers aren’t always 100 per cent accurate. But they may help to give you a better picture about how long you really sleep for.

What should I do with the results of my sleep diary?

The information in your sleep diary might help you to understand your sleep patterns better. It can also help you notice areas of your daily routine that might need changing. From this information, you could try some simple changes to help improve the quality of your sleep. For example, switching off your electronic devices earlier in the evening, or avoiding alcohol before bed.

If these changes don’t improve your sleep, it may be worth showing your sleep diary to a healthcare professional. They may be able to see if you have a sleep disorder, such as insomnia or sleep apnoea. Treating these conditions can help improve the quality of your sleep and day-to-day life.

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Amy Gallagher
Amy Gallagher
Senior Sleep Physiologist at Cromwell Hospital

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    • Sleep and mental health. Mind., published May 2020
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    • How sleep deprivation affects your heart. The Sleep Foundation., updated December 2020
    • How much sleep do we really need. The Sleep Foundation., updated March 2021
    • Personal communication, Amy Gallagher, Sleep Physiologist at Bupa, January 2022
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    • Robbins R,et al. Sleep tracking: A systematic review of the research using commercially available technology. Curr Sleep Med Rep 2019; 5(3):156–63. doi: 10.1007/s40675-019-00150-1

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