What the world’s largest sleep survey could reveal about health and disease

Almost 180,000 UK Biobank participants answered nearly 140 questions about their sleeping habits. The results could revolutionise treatments for sleep disorders and reveal how sleep keeps us healthy.

“Life cannot exist without sleep,” says sleep scientist Eti Ben-Simon from the University of California in the US. Most animals, even ‘simple’ ones such as roundworms and jellyfish, sleep. Yet we know a lot less about how sleep supports a healthy life than we know about the role of diet and exercise.

The almost 180,000 UK Biobank participants who answered nearly 140 questions about their sleeping habits could help to change that.

A small amount of previously collected information about UK Biobank participants’ sleeping habits had already offered researchers a tantalising glimpse into the benefits of napping, the importance of regular bedtimes or the health impact of daylight saving time.

The new survey data will let scientists delve much deeper into how our sleeping habits affect the risk of conditions ranging from depression to heart disease. Researchers studying sleep disorders will be able to explore what causes conditions such as obstructive sleep apnoea, shift work disorder and restless leg syndrome. The data may even reveal the exact kind of sleep that keeps us healthy.

Why sleep science matters

“Sleep has been very much of an undervalued field to study for the past decades,” says health researcher Hang Yuan from the University of Oxford, UK. Researchers have traditionally relied on observing small groups of people, often in sleep labs. For these experiments, “we usually have 30, maybe 40, participants”, Ben-Simon says. “That's why I love UK Biobank data, because these are numbers that I can only dream of.”

 

“I think the most important thing is for the sleep community to start moving towards using cohort-based studies like UK Biobank,” says Yuan. The sheer number of UK Biobank participants who answered to the sleep questionnaire will make it possible to pinpoint links between sleep and health with more certainty – and for substantially lower cost than with experimental studies, he explains.

Yuan expects that the data will attract wide interest from well beyond the sleep research community: “It's hard for me to think about something that people research that has nothing to do with sleep. What this survey [data] really allows people to do is to understand sleep in the context of many complex diseases and in combination with many other modalities, like brain imaging data.”

An underdiagnosed issue

The survey data give scientists deeper insight into more than 30 sleep disorders, including insomnia and narcolepsy. “Sleep disorders are a massively underdiagnosed issue,” says Yuan. One reason might be that people seem to be hesitant to see their doctor when they have symptoms.

One study looked at more than 160,000 UK Biobank participants, 29% of whom had said that they experienced insomnia when they were asked during their first, ‘baseline’ visit to UK Biobank. But only 6% of had this issue listed in their healthcare records. “It showed that people don't tend to go to the GP about sleep problems,” says sleep specialist Melanie de Lange, who led the study at the University of Bristol, UK.

 

Some people may think that sleep problems aren’t important, or they might be worried about being prescribed sleeping tablets, de Lange suggests. “There's a strong need for better therapies for sleep disturbances,” says Richa Saxena, a geneticist at the Massachusetts General Hospital, US. “There is a huge opportunity in therapies that are more based on basic science understanding of sleep. It's an area that's really not been explored.”

How to sleep well

The new survey data may also help scientists to create better sleep recommendations. Public health guidelines typically don’t go beyond suggesting seven to nine hours per night – that’s not detailed enough, researchers argue. “It's not just about how long you sleep,” says Yuan. “It's about the quality of your sleep, the timing, the continuity and even the architecture of your sleep stages.”

Sleep regularity is an important factor, as movement data from 100,000 activity-monitor-wearing UK Biobank participants has previously shown. People who went to bed and got up at the same time every day had a lower risk of heart attacks, stroke and death. “The more precise you can be in your wake-up time or bedtime, it seems to be better for many health outcomes,” explains population health scientist Jean-Philippe Chaput from the University of Ottawa, Canada, who led one of the studies.

Activity data from UK Biobank participants also revealed that the autumn clock change doesn’t actually let us sleep an extra hour. “[People] are only getting about half an hour more sleep than on the previous and following Sundays,” explains de Lange, who led the work. “This study...can hopefully, in some small way, help policy makers make informed decisions as to whether to stop the clock changes,” she adds.

Cause and effect

Neuroscientist Valentina Paz from the University of the Republic, Uruguay, hopes that healthcare professionals will start to pay more attention to the benefits of sleep. Her team’s analysis of almost 400,000 UK Biobank participants’ data – including brain scans from 35,000 participants – revealed that daytime naps keep the brain bigger for longer. People who napped regularly had slightly larger brains than non-nappers, seemingly delaying the natural decline in brain volume we all experience as we age.

Yuan is keen to further explore napping with the new questionnaire data. While studies like Paz’ show that naps can be beneficial, feeling the need to sleep during the day can also be a result of poor health that leaves people tired. For example, a 2022 analysis of information from UK Biobank participants had linked regular naps to high blood pressure and stroke.

Paz explains that UK Biobank data is key to untangling cause and effect: “We use a technique that is called Mendelian randomization; you need a large amount of data to do it, and you need genetic data and health data.”

Saxena’s team is also interested in combining the survey results with UK Biobank participant’s genetic data to explore inherited influences behind sleeping disorders. “We have about 50 different parameters that we want to study,” she says. “We’re ready to go.”

To find out more about the survey data, and hear from UK Biobank researchers and participants, read our news story.