Waking up to the importance of sleep

A woman asleep on her side in bed

Sleep: We spend about one-third of our life doing it (or attempting to); cats do it for an average of 15 hours a day, whereas giraffes only need 1.9 hours of it a day. But why do we do it? How can we do it better? And what happens when we can’t sleep?

Why do we sleep? 

The NHS advises that most adults need between 6 and 9 hours of sleep every night. We still don’t know exactly why we sleep, but we do know that poor sleep can have a detrimental effect on our health. There are various theories on why sleep is needed, although no scientific consensus. These include: 

  • To reset connections between brain cells 
  • To process information from the previous day 
  • To clear damaged proteins and waste from the brain  

Professor Nick Franks, Professor of Biophysics and Anaesthetics at Imperial College London researches the neuroscience of sleep and what is understood about its role. His lab, shared with Professor Bill Wisden from the Faculty of Natural Sciences, seeks to understand how and why we sleep.

Speaking at an Imperial College Academic Health Science Centre seminar, Professor Franks said: “It’s astonishing that we still don’t yet know why we sleep. Research has shown the effects of poor sleep, such as reduced mood and concentration as well as increasing the risk of serious conditions such as obesity, heart disease and diabetes. There are many different theories as to why we need to sleep and at Imperial we are exploring and developing our own theories so we can potentially develop new ways of treating a range of diseases linked to poor sleep.” 

These theories could lead to new ways of treating a range of diseases that may be linked to poor sleep, such as dementia.  

In the seminar, Professor Franks described research from a team in Australia looking at cognitive impairment following poor sleep over a period of 24 hours. Study participants were asked to perform a simple hand eye coordination test after varying levels of sleep deprivation. The researchers found that participants’ performance on the test declined with sleep deprivation, especially in participants who had less than six hours of sleep. The team found that with about 24 hours of sleep deprivation, people’s performance was impaired to a similar extent to that seen in people at the drink-driving limit. 

The consequences of a lack of or poor sleep are widespread and can be more serious than just a lack focus or a bad mood. A solid night's sleep seems to be essential for a long and healthy life.  

A scan of the brain

Sleep disorders

Obstructive sleep apnoea (OSA) is the most common sleep-related breathing disorder, estimated to affect around 1 billion people worldwide. OSA is a condition where the walls of the throat relax and narrow during sleep, interrupting normal breathing and causing disrupted sleep. The condition mostly affects people who are overweight or older in age. It can affect quality of life as well as increase the risk of high blood pressure, heart problems, stroke, and potentially memory problems. 

For people with moderate or severe OSA, doctors usually recommend a continuous positive airway pressure (CPAP) device, a small pump that delivers pressurised air into the nose through a mask, stopping the throat from closing. Previous studies have established the benefits of CPAP in middle-aged people with OSA, but until now there has been little research on whether the treatment is useful and cost-effective for older patients. The global population aged 80 years and over is projected to triple, from 143 million in 2019 to 426 million in 2050, and as a result cases of OSA will rise. 

Professor Mary Morrell is Professor of Sleep and Respiratory Physiology at the National Heart and Lung Institute and works to develop new treatments to treat obstructive sleep apnoea. In collaboration with clinical doctors across the UK, Professor Morrell found that the CPAP device can be just as effective in older patients as it is in younger people and leads to a reduction in how sleepy patients feel in the daytime. It also reduces healthcare costs. Professor Morrell and her colleagues hope that their research means that more patients will be able to benefit from CPAP treatment. 

Speaking at an Imperial College Academic Health Science Centre seminar, Professor Morrell said: “The prevalence of breathing problems when people go to sleep is increasing, especially in older people and those who are obese. This will continue to rise as the population of older people increases, and with the rise in obesity. It is a healthcare problem that we can’t afford to ignore. We need to find new ways to treat sleep disorders so we can improve people’s quality of life and their health.” 

Research from Professor Morrell and team also found that CPAP treatment can improve energy levels and vitality (sleep quality, energy levels and daytime sleepiness) in those with a mild case of sleep apnoea - the treatment was previously only recommended for people whose sleep apnoea is moderate to severe. The research, which studied over 200 patients, was one of the first to investigate the use of the treatment for mild cases. 

A man asleep in bed wearing a CPAP machine

Technology to monitor sleep

When putting technology and sleep together, most people think of the negative impact screens have on quality of sleep. But what if technology could help people to sleep better, and detect when things are going wrong? Based in Imperial’s Department of Electrical and Electronic Engineering, the Wearables Technologies Lab is trying to do just this. 

As well as Obstructive Sleep Apnoea, common sleep disorders include REM Sleep Behaviour Disorder (RBD), narcolepsy, sleepwalking and night terrors. Diagnosis of sleep disorders is an expensive and time-consuming process that requires a sleep study, known as a polysomnography, to be undertaken in a controlled environment. This typically involves using many electrodes to monitor and record physiological parameters together with brain activity, eye movements and muscle activity. These signals are then analysed and scored by clinicians to determine if there is any abnormality recorded during sleep.  

The Wearable Technologies Lab, led by Professor Esther Rodriguez-Villegas, is carrying out research aiming to take this process from the hospital to the patient’s home. This would not only save money but would also provide a familiar and comfortable environment for patients. The team are developing tiny wearable devices that can easily be put on by patients during sleep to monitor neural activity, analyse overnight signals and automatically identify unusual patterns that can be helpful for clinicians.

Four hands holding tiny wearable devices to be worn during sleep

Examples of wearable devices to monitor sleep (credit: Wearable Technologies Lab).

Examples of wearable devices to monitor sleep (credit: Wearable Technologies Lab).

Impact of technology on sleep

The NHS advises avoiding using smartphones, tablets or other electronic devices for an hour before going to bed, as the blue light from the screen on these devices may have a negative effect on sleep. Blue wavelengths, which are useful during daylight to boost attention, reaction times and mood, seem to be most disruptive at night. Exposure to light suppresses the secretion of melatonin, a hormone that influences circadian rhythms. Even dim light could interfere with a person’s circadian rhythm and melatonin secretion. While any kind of light may suppress melatonin production, blue light at night does so more powerfully.  

Researchers at Imperial found that pre-teens who use a mobile phone or watch TV in the dark an hour before bed are at risk of not getting enough sleep. The study, published in 2019, was the first to analyse the pre-sleep use of media devices with screens alongside the impact of room lighting conditions on sleep in pre-teens. They found that night-time use of phones, tablets and laptops is consistently associated with poor sleep quality, insufficient sleep, and poor perceived quality of life.  

Previous studies have shown that sufficient sleep duration and quality are vital in childhood to maintain physical and mental development. Sleep is also crucial for cognitive processes and a lack of sufficient sleep has been directly related to poor academic performance.  

A smartphone screen showing a sleep tracking app
A smartphone screen showing a sleep tracking app
A smartphone screen glowing in the dark
A smartphone screen glowing in the dark

Light and wellbeing 

An Imperial-founded student start-up, LYS Technologies, has created a wearable device that helps people to manage the impact of artificial light on their health and wellbeing. Christina Petersen, co-founder and Innovation Design Engineering graduate, was inspired by research suggesting that nurses who work night shifts – and are therefore more exposed to blue light – have higher rates of breast cancer, diabetes and cardiovascular disease. Speaking to The Guardian, Christina said: “I think people are very focused on what they eat and exercise, but light is so essential to life on the planet it’s been neglected in the health calculation.” 

When it comes to light intake, intensity, colour, timing and duration matter. When screens with blue light suppress melatonin, or an office is too dark, the result is a disruption to the circadian rhythm – in the long-term, this is linked to illnesses, as well as affecting our sleep and energy levels in the short-term.  

Christina and co-founder Hugo Starrsjo developed a wearable light-tracking device the size of a £2 coin to help people monitor the kind of light they’re exposed to throughout the day. The device links to a smartphone app and allows the user to see how the light in their everyday life affects their health, enabling them to find the right light for their personal sleep-wake cycles. 

In 2016 Christina was a finalist in Imperial’s WE Innovate programme, the College’s entrepreneurial programme for women. 

A man wearing a light sensor attached to his pocket

Student sleep habits

According to recent research from King’s College London, almost four in 10 university students are addicted to their smartphones, a habit that has a detrimental effect on sleep. More than two-thirds (68.7%) of those addicted to their smartphones had trouble sleeping.  

Imperial’s student Sleep Society, founded in 2017, aims to improve sleep awareness and sleep hygiene in the student community. The Society is run by a team of engineering students as an educational platform not just to research sleep but to help promote better sleep patterns. The Society hears from many students that poor sleep is a common problem, which can lead to more serious problems when they’re older.  

To combat this and improve the quality of sleep in the Imperial community, the Society organises workshops with academics and sleep experts, shares resources and tips for good sleep and offers opportunities to attend lectures on sleep. 

The Society is particularly interested in the link between sleep and mental health in students, specifically whether improving sleep can improve mental health. They recently partnered with the International Sleep Charity to conduct a Cognitive Behavioural Therapy course for students with insomnia (CBTi). Students were either placed on a Short Sleep Hygiene Course for three weeks or a longer full CBTi course for six weeks. Students who completed both courses reported more time asleep, better sleep quality and less morning fatigue.

The Society is led by fourth year Aeronautical Engineering students Nikhil Dawda, Patryk Kulik and Easha Tu Razia.  

An Imperial student studying in the library
An Imperial student studying in the library

Crunching data while you sleep

Despite the negative impact of technology on quality of sleep, is there a way that technology could be used during sleep in a positive way?  

Thousands of people around the world have helped Imperial to accelerate COVID-related research by recruiting their smartphones while they sleep. By running Vodafone Foundation’s DreamLab app while their phone is charging overnight, citizen scientists have proffered their processing power to help in the search for drugs and ‘Hyperfoods’ that could potentially help those with COVID-19.  

The processing power of thousands of smartphones is harnessed which, when combined, can analyse huge volumes of data in less time than it would take a supercomputer, and at a fraction of the cost of cloud computing platforms. While the user sleeps, the app downloads a small bite-sized packet of data – roughly 5 MB in size – and uses the phone’s processors to run millions of calculations, before uploading the results and clearing the data. 

The DreamLab app is also helping researchers to speed up the delivery of personalised cancer treatments

A smartphone screen with the Vodafone DreamLab app

What next?

A woman has a brain scan while sleeping

While many aspects of sleep remain a mystery, what’s clear is that researchers and academics from across Imperial will continue to play a key role at the forefront of discoveries into this vital part of our lives. There’s also no doubt that technology will play an ever-increasing role, both in researching why we sleep but also in informing us how to do it better.

Photo credits

Sleep and wellbeing image: LYS Technologies
Library image: Thomas Angus / Imperial College London
DreamLab app: Vodafone Foundation