Sleep - the best medicine?

One in three people in the UK experience poor sleep — so how can you improve yours?


One in three people in the UK is said to experience poor sleep, but how does poor sleep affect health?

We investigate the different stages of sleep, the effects of sleep on your health, and how you can improve your sleep.

What is sleep?

To most, sleep is just a thing that you do. You pop your head down on a pillow, close your eyes, and the next thing you know, you open your eyes, and hours have passed.

But what is sleep?

Everyone needs sleep, but its biological purpose remains a mystery. Sleep is a complicated process that affects how you function in ways scientists are only now beginning to understand [1].

However, we do know that during sleep, you progress through sleep cycles, each lasting, on average, roughly 90 to 110 minutes.

During these cycles, you progress through five different phases – stage one, two, three, four, and rapid eye movement (REM).

The different stages of sleep [2]:

  • Stage one – Light sleep is where you drift in and out of sleep. If you are in light sleep, you can wake up with ease and may be able to remember some images from dreams or experience feelings like falling and waking up with a sudden jump.
  • Stage two – Your brain waves start to slow down, and your eyes stop moving.
  • Stage three and four – When deep sleep happens, your brain waves slow down and exclusively emit delta waves. Delta brain waves directly link to deep sleep and can be measured using an electroencephalogram (EEG). It is harder to wake someone in stages three and four of sleep. If you wake up in these stages, you may feel disorientated and grumpy.
  • REM – REM sleep usually starts around 70 to 90 minutes after you fall asleep. As the night progresses, REM sleep periods increase in length as deep sleep decreases. When you switch to REM sleep, your breathing becomes more rapid, irregular, and shallow, your eyes jerk rapidly, and your limb muscles become temporarily paralysed. Your heart rate increases, and your blood pressure rises. If you wake up during REM sleep, you may be able to recall strange dreams. 

What controls sleep?

You have two internal biological mechanisms, also referred to as clocks. They are your circadian rhythm and your sleep-wake homeostasis, which work together to regulate when you are awake and sleep. 

Your circadian rhythm controls your timings of sleep. Your circadian rhythm synchronises with environmental cues such as light and temperature. It makes you feel sleepy at night and wakes you up in the morning without an alarm.

Our genetic make-up can play a part in our circadian rhythm. In 2017, Jeffrey C. Hall, Michael Rosbash, and Michael W. Young received a Nobel prize for their circadian rhythms research. By studying fruit flies, they isolated a gene that produces a protein that builds up cells overnight, then breaks down during the day. This process affects when you sleep, your brain functions, and more [3].

Sleep-wake homeostasis reminds the body to sleep and regulates sleep intensity. The sleep drive gets stronger the longer you are awake and therefore causes you to sleep for longer and more deeply after a period of sleep deprivation.

Sometimes other factors can affect your sleep-wake needs.

Factors that affect your need for sleep:

  • Medical conditions
  • Medication
  • Stress
  • Sleep environment
  • Diet

Why do we need to sleep?

Sleep affects almost every tissue and system in the body – from the brain, heart, and lungs to metabolism, immune function, mood, and disease resistance.

Most adults need between six and nine hours of sleep every night [4]. However, one in three of us suffers from poor sleep [5]. Poor sleep can lead to sleep deficiency, which can be dangerous long-term.

Reasons for sleep deficiency include:

  • Not getting enough sleep.
  • Not sleeping long enough or getting a good quality of sleep.
  • Sleeping during the day, meaning your body clock is out of sync.
  • Having a sleep disorder that prevents you from getting enough sleep or causing poor quality sleep.

What can cause a bad night’s sleep?

Different factors can cause a bad night’s sleep, from not having a routine to having caffeine too late on in the day.

Mental health

Your mental health and quality of sleep are closely linked. Poor mental health may affect your ability to get to sleep, and poor sleep can affect how you feel the next day.

If you find it hard to fall asleep, stay asleep, or wake up earlier than you would like to, then you may be experiencing insomnia. Panic attacks, flashbacks, nightmares, or psychosis can disturb you when you are asleep, and low mood or low self-esteem may mean it is hard for you to wake up or get out of bed.

Have a look at Mind’s contacts for sleep support if you are frequently feeling tired or sleeping at times when you need to be awake.

Poor sleep could also be down to stress. Our Stress Cortisol Saliva Tests (4) can help you to understand your stress levels over the course of the day and help to see if your cortisol could be affecting your wellbeing, or sleep pattern.

Shift work

Night workers make up 12% of the UK workforce. If you work shifts, your sleeping pattern and circadian timing can become affected. Long-term, 10-30% of shift workers are diagnosed with shift work sleep disorder, where they have experienced chronic sleep and circadian disruptions.

Sleep and circadian timing are both essential biological processes that affect many aspects of physical and mental health. Working shifts can heighten your risk of sleep problems, occupational and driving accidents, and health conditions such as cardiovascular disease [6]. People who work shifts tend to have shorter and poorer quality sleep during the day.

If you work shifts, take extra care to make sure you are getting enough quality sleep.


Environmental factors that may influence sleep include [7]:

  • Temperature – We sleep best when our environment is colder than usual at night. If your room is too warm, then it may be affecting your sleep.
  • Noise – Limit noise around you. If this is not an option, try listening to music that has binaural beats at a delta frequency of 3hz – the same wavelengths that your body emits during deep sleep [8].
  • Too much light – If it is too bright, your body may resist falling asleep. A black-out blind or sleep mask can help. Limiting blue light an hour before bedtime can also help with getting better sleep.
  • Safety – Sleeping can make you feel very vulnerable. Make sure you know that your doors are locked, and your house is safe before falling to sleep.

Sleep apnoea

Sleep apnoea is when your breathing stops and starts whilst you sleep [9]. Because your breathing is stopping and starting, you may wake up during different stages of sleep cycles, and your circadian rhythm could be affected.

Sleep apnoea can cause:

  • Fatigue
  • Lack of concentration
  • Mood swings
  • Headaches when you wake up
  • Low testosterone levels in men

If you think you may be experiencing any symptoms of sleep apnoea, you can use the Epworth Sleepiness Scale questionnaire (a questionnaire designed to help diagnose sleep apnoea).

If you suspect you have symptoms, fill in the questionnaire and take your answers to your GP.

How is poor sleep risking my health?

Poor sleep can affect both your mental and physical health. Here are six ways that sleep impacts your health. 

Six ways sleep affects your health [10]:

  1. Sleep boosts immunity – Prolonged lack of sleep can disrupt your immune system, meaning you are less able to fight off common colds and viruses.
  2. Sleep can help you lose weight – People who sleep less than seven hours a day tend to gain more weight than those who get more than seven hours. This could be due to the reduced levels of leptin (the chemical that makes you feel full) and increased levels of ghrelin (the hunger-stimulating hormones) when sleep-deprived.
  3. Sleep helps with mental health – Chronic lack of sleep may lead to long-term mood disorders like depression or anxiety.
  4. Sleep can help prevent diabetes – People who sleep less than five hours a night have an increased risk of developing diabetes. Missing out on deep sleep changes the way the body processes glucose, leading to type 2 diabetes.
  5. Sleep wards off heart disease – Sleep deprivation is linked with increased heart rate and blood pressure and higher levels of chemicals linked with inflammation, which may put extra strain on the heart.
  6. Sleep increases fertility – Regular sleep disruptions can cause infertility by reducing the secretion of reproductive hormones.

How to get a good night’s sleep 

From better sleep hygiene to having a consistent routine, there are steps that you can take to get a better night’s sleep. We have put together six ways to help you get a better night’s sleep.

Six ways to get a better night’s sleep:

  1. Exercise during the day - 20 – 30 mins of exercise a day can help you feel tired later on, but do not exercise too close to your bedtime. If the gym isn't for you, there are other ways to get your body moving.
  2. Avoid bright lights and loud sounds before bed – Turn off your TV and phones, as the blue light can affect your circadian rhythm, keeping you awake.
  3. Do not lie in bed wake – Try reading or listening to a podcast until you feel tired. If you are struggling to relax, you can find some ideas on how to help in our top ten ways to de-stress blog.
  4. Take time to wind down – Taking a warm bath, writing a list to organise your thoughts, or listening to relaxing music can help you wind down and decompress after a busy day.
  5. Avoid caffeine – Switch to de-caff drinks from about midday onwards and avoid caffeine in the evening before going to bed.
  6. Have a consistent routine – Going to bed and waking at the same time every day can help sync your circadian rhythm and help you get a better quality of sleep. Even if you don’t get a good night’s sleep, make sure you still get up at the same time. That includes weekends, too.

Sleep organisations that can help

British Snoring & Sleep Apnoea AssociationThe British Snoring and Sleep Apnoea Association covers information and support for people affected by snoring and sleep apnoea.

The Sleep Charity: The Sleep Charity, incorporating The Sleep Council, provide advice and support to empower the nation to sleep better. They offer support for adults, teenagers, and children to get a better night’s sleep.

Mind: Mind explains how mental health problems can affect sleep and vice versa. They have a list of resources and contacts if you’re struggling with your mental health and getting a good night’s sleep.


  1. Walker, M., 2018. Why we sleep. [London]: Penguin Books. 

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