We all sleep – but why is it necessary, and what happens when we have trouble sleeping? Read on to discover why it is so important for your overall health to get quality sleep.

What is sleep?

Sleep is a fundamental human requirement that has restorative functions. Quality sleep is as essential to survival as food and water.

In total, we spend about one-third of our lives sleeping or attempting to sleep. As the noted pioneer of sleep research Allan Rechtschaffen states: ‘If sleep doesn’t serve an absolutely vital function, it is the biggest mistake evolution ever made.’

During sleep, tissue grows and repairs itself and the immune system is strengthened. Without sleep, it’s not possible to form and maintain pathways in your brain which can, among other things, help you create new memories. Not getting enough sleep makes it harder to concentrate and has an impact on alertness and response times.

Everyone needs sleep, and research has shown that a chronic lack of sleep, or consistent poor-quality sleep, increases the risk of disorders including high blood pressure, heart disease, diabetes, depression, and obesity.

What is good sleep?

Good sleep leaves you feeling rested and ready for the day and tasks ahead.

In order to have ‘good’ sleep, you need to enter the rapid eye movement (REM) stage of the sleep cycle. This is one of the two basic types of sleep, the other being non-REM sleep. Both REM and non-REM sleep are linked to specific brain waves and neuronal activity.

You will experience all stages of non-REM and REM sleep several times during a typical night. A good night’s sleep typically comprises four or five cycles, with each lasting around 90 minutes. It’s important to experience all four stages – the three different non-REM sleep stages plus REM sleep – in order to wake up feeling rested.

As you drift off to sleep, you may experience body twitches or jerks; this is normal as the body enters a very light stage of sleep from which you can be easily roused.

Stage two of non-REM sleep is also quite a light sleep as the body prepares for the deeper sleep that will happen in stage three. It is difficult to wake someone in stage three sleep; if you are roused at this deep sleep stage, you may feel disorientated and a bit groggy. This stage provides the most restorative sleep.

Once you’ve gone through the three stages of non-REM sleep, you enter REM sleep, during which the brain is more active. It is at this stage in the sleep cycle that you may dream. REM sleep is important for mental and emotional development.

While you sleep, your brain and body work hard. Your brain processes and stores events from the day, while the body releases a number of different hormones, including a growth hormone from your pituitary gland, which helps the body repair itself.

Sleep allows the sympathetic nervous system, which controls the flight or fight response, to relax while giving the immune system an opportunity to release small proteins that help the body fight inflammation or infection. The brain also releases a hormone that stops the need to go to the toilet while asleep.

So, while you are getting a restful night’s sleep, your body is working on keeping you healthy.

Causes of poor sleep

It’s common to have brief instances of poor sleep. Stress and worry can lead to difficulty drifting off, while illness, stress, and anxiety can cause restless nights. Changes in life circumstances – most notably having a newborn baby to look after – can lead to poor sleep. These causes tend to be temporary and should resolve themselves after a period of time. Other behaviours that can lead to poor sleep include drinking caffeine or alcohol close to bedtime, or using screens in bed.

When short instances of poor sleep become longer stretches, it can start to impact other areas of life, making manageable tasks much harder. In some cases, it may be necessary to seek advice from a doctor.

Things to look out for

A lack of quality sleep can have an impact on mood and lead to feelings of irritability, as well as affecting concentration and alertness. If you regularly wake up feeling tired and this starts to become disruptive to your daily life and general health, it might be helpful to try making changes to your sleep routine.

Who might be susceptible to poor sleep?

The amount of sleep needed varies throughout life and between individuals. Babies spend a huge proportion of their time asleep, while the average time an adult needs or might expect to sleep is around eight hours a night. However, there is no ‘normal’ length of time; it is a matter of whatever is natural for each person.

People who work shifts can be more susceptible to sleep problems, as the work schedule interrupts the natural wake-sleep cycle. Shift workers can be prone to insomnia.

As sleep is a fundamental human requirement which is necessary for our healthy functioning, it’s important for everyone to be aware of what is normal for them and do what they can to get quality sleep.

What can we do to maintain good sleep health?

There are plenty of ways to help ensure a good night’s sleep. The key is to have a regular sleep routine. This can involve the environment you sleep in – such as making sure the room is quiet and dark – as well as the behaviours leading up to bedtime. These measures are known as ‘sleep hygiene’ and can impact the chances of having a restful night with good sleep.

The key to a good night’s sleep is the production of the natural hormone melatonin, which helps control sleep patterns. It’s produced during the hours of darkness and encourages sleep. Melatonin supplements can help reduce the time it takes to fall asleep and alleviate subjective feelings of jet lag.

Alcohol, caffeine and exercise should be avoided before bed, and screen time should be limited. It is not recommended to look at mobile or tablet screens in bed as they produce a blue light which has been shown to affect the ability to go to sleep by blocking the production of melatonin.

Natural and artificial blue light can have an impact on alertness; think how energised you feel in the bright sunshine. Exposure to all light impacts the body’s natural sleep-wake cycle, but too much blue light can stop the body winding down for sleep. It’s recommended that screen use is avoided for two hours before bed; if this isn’t possible, glasses that block blue light could be a solution, or try switching electronic devices to ‘night mode’.

There are plenty of other suggestions for effective sleep hygiene to help promote a relaxed and calm state ready for sleep. These include:

  • Engaging in relaxing activities in the lead-up to bedtime – for example, a warm bath with scented candles, meditation, reading or listening to peaceful music.
  • Sticking to the same waking time, even at the weekend.
  • Only going to bed when sleepy, and getting up again if you are still awake after 20 minutes.
  • Setting a bedtime that will allow for a solid seven hours of sleep. In other words, don’t go to bed after midnight if you need to be at work for 8 am.
  • Making the bedroom a calm environment, not too hot or too cold, and keeping it quiet and dimly lit.

Some natural herbal supplements can also be used in conjunction with sleep hygiene practices to promote relaxation and sleep and lead to a restful night.

Look into our Consumer Health section and discover Seripnol, a natural treatment that will help you fall asleep faster and maintain a better quality and duration of sleep during the night thanks to the joint action of melatonin, magnolia, jujube and L-teanin. Especially if you are undergoing stressful moments, your sleep can be greatly affected and the lack of a good night’s rest can be detrimental to how you affront the challenges of the day ahead.

Scientific studies

There have been numerous studies into sleep, including the impact that getting too little sleep can have on health and public safety, and how sleep affects psychological and neurological functions, like memory.
More recently, research has focused on how the COVID-19 pandemic has affected our sleep. Research published in The Lancet highlighted some of the global work on COVID-19-related sleep disorders.

Referenced sources

  1.  Institute of Medicine (US) Committee on Sleep Medicine and Research; Colten HR, Altevogt BM, editors. Sleep Disorders and Sleep Deprivation: An Unmet Public Health Problem. Washington (DC): National Academies Press (US); 2006. 3, Extent and Health Consequences of Chronic Sleep Loss and Sleep Disorders.
  2.  Partinen M. Sleep research in 2020: COVID-19-related sleep disorders. Lancet Neurol. 2021;20(1):15-17. doi:10.1016/S1474-4422(20)30456-7
You might be interested in…


Stress is a common by-product of modern, busy lives. It infects work, home, relationships with multiple triggers that often appear beyond our control.