If you get a decent night’s rest regularly, you’re likely to be slimmer, happier and healthier. So why are we getting worse at sleeping, not better? The Times science editor Tom Whipple investigates.
Back when commercial sleep trackers were new, Simon Kyle, from Oxford University, decided to conduct a study. He gave wearable devices to people who already had sleep problems and told them he was going to see how their performance in the day was affected by their sleep the night before.
He knew and his subjects knew just how important sleep was. By this time - 2018 - good sleep had already joined diet and exercise in the holy trinity of a healthy lifestyle.
Study after study had shown how sleeping badly affected our health, both physical and mental. It impaired both day-to-day and long-term cognitive performance. Poor sleepers got fatter, sadder, sicker and stupider. So it was not surprising that “eight hours” had become the new “five a day”.
Six years later and we now have watches, eye masks and rings that have been repurposed to log sleep. We can put phones under our pillows to listen out for sleep apnoea, and smart mats under our sheets to track our tossing and turning.
Then there are the remedies. You can buy weighted blankets to put above you and temperature-controlled mattresses for below - heating and cooling to match your core body’s requirements for each cycle of sleep. TikTok influencers promote the “sleepy girl mocktail”, a (supposedly) sleep-inducing drink that very much lacks the now verboten but more traditional sleep inducer - alcohol.
It is easy to mock. Something our ancestors did without thinking has become app-tracked, app-controlled and very, very lucrative. Yet our behaviour makes sense. The data is clear: better sleep means better lives.
That too is what Kyle found in his study. Each morning he gave the participants the sleep score from their tracker. Then throughout the day he asked them how they were getting on.
I set the alarm for an hour before I need to get up. If my chap is here, we make love ... Then I reconstruct my dreams - some good, some disturbing.
The results matched exactly what you would expect. Those with the lowest scores were less alert, had impaired function, lower mood and increased sleepiness. All their fears were true.
Except, there was a very big catch. The sleep scores they had been given weren’t real. It was all in their mind.
Sleep is important. This is incontrovertible. Sleeping badly has been linked to heart disease, strokes, diabetes, obesity, dementia — and almost any other modern disease you care to mention. How much of what we are doing to improve it, though, is helping? And is our anxiety about it becoming counterproductive?
In 1989, the actress Helen Mirren explained her morning routine. “I always set the alarm for an hour before I need to get up,” she said. “If my chap is here, we make love … Then, half-dozing, half-awake, I reconstruct my dreams. Some are good while others are profoundly disturbing.”
Back in my early Microsoft days, I routinely pulled all-nighters. I wasn’t as sharp operating on caffeine and adrenaline.
The same year, Ruby Wax was also interviewed about her day for the A Life in the Day feature in The Sunday Times. “These people who start their day with some lemon juice, muesli and bran — who are they?” she asked. “They’re not part of my world. Neither is 6.15am. I have no idea what 6.15am looks like.” She didn’t so much wake up, she said, as gradually emerge. “This morning was typical. I got up a few times before the real thing.”
Twelve years later, Gordon Ramsay’s answer was different again. “I remember walking into the kitchen absolutely shattered one morning. The chef said, ‘How long did you sleep last night?’ I said, ‘About five and a half hours.’ He said, ‘Too long.’ He went on to say that by the time I was 60 I would have wasted 20 years of my life. I’ve slept less since then.” At the time he was interviewed, he complained he was often awoken by his two-year-old daughter, “playing ding-ding-daddy with my willy”. He had taken to wearing pants.
They are all very different. But if you read some of the more recent answers, you notice a commonality - something they largely lacked before about 2005. This quality might best be described as reverence. For today’s respondents, sleep isn’t something to be defied but deified. Not indulged but improved. Sleep is there to be protected, logged and nurtured.
In 2021, the actor Orlando Bloom was featured in the same column. “I have a smart ring sleep tracker and the first thing I do is look at the app to see if I’ve had a good sleep and check my readiness for the day.” Then he takes some “green powders” and “brain octane oil” - what would Ruby Wax think of that? - before going to bed in time to ensure eight hours. “I’m happy, and so is my sleep tracker.”
Since the turn of the century, sleep has become serious. It has done so, in part, because sleep is indeed serious. For some conditions, poor sleep is clearly a cause. For others, it can be a useful symptom. For many, it is both. “Mental health problems have increased over the past decades, and I think that’s probably tracking to the changes in sleep,” Kyle says. Sleeping badly can lead to depression. Being depressed can lead to staying inside. Being inside means you lack the light exposure or exercise that leads to good sleep.
I can’t sleep without being overly full. I take two hardboiled eggs to bed and eat them when I randomly wake up. It used to be beef jerky, but I’d wake up too puffy.
Sleep has also become serious because, at least anecdotally, we are getting worse at it. “The level of complaints seem to be in part an expression of our modern living,” Kyle says. Maybe, he says, it’s a consequence of how we use technology to extend the day — at the same time as working in buildings that extend the night.
We work indoors. We use artificial light in the office, then in the home. Day and night are smooshed into an endless crepuscular existence. Yet this existence is also superstimulated. “We live,” Kyle says, “with endless incoming streams of sensory information.”
But something else has happened too. Tonight, if you want to sleep better, not only can you buy the right trackers, tonics and tinctures (magnesium foot spray? Pillow mist?), you can also follow sleepfluencers or “sleepmaxxers”, who give their tips for optimising unconsciousness. And why not? Good sleep is great. These new social media stars are, to an extent, what Michael Mosley was to diet or Mr Motivator to lurid Lycra and bouncing around. Except they’re not quite the same. You can motivate yourself from couch to 10k or from cheeseburger to bean burger. Can you motivate yourself asleep?
As anyone who has lain awake at night counting the hours left before an important day knows, you cannot worry yourself into better sleep. You cannot think your way to eight hours. To catch 40 winks, you have to pin them down without seeking them. Sleep creeps up on you when you aren’t looking. Today, though, a lot of us are looking.
“People contact us who are quite obsessed with sleep,” Kyle says. “They become preoccupied with the measurements of sleep and the feedback.” Sometimes, people have simply got it wrong. “People seek help because they experience having a sleep problem, not because, necessarily, they’ve objectively got a sleep problem.” When Kyle and his colleagues measure them properly, often they find they are sleeping fine - yet their lives are blighted, apparently, by insomnia.
And that’s related to what he really found in his study, which concluded that people who had worse sleep scores went on to have worse days. Because the catch was, the sleep scores he gave people were randomly generated. They were a lie. Yet the consequences of the lie were real.
In 2017, a year before he published his study, Kelly Baron, from the University of Utah, wrote a paper. Increasingly, colleagues had seen a different sort of problem in their sleep practices. The paper cited a few examples.
There was the 40-year-old man given a sleep tracker by his girlfriend who claimed he had light and fragmented sleep. He complained of cognitive difficulties - but only occurring on days when his tracker showed fewer than eight hours.
I’ve tried to sleep less, but even though I’m awake more hours, I get less done. The brain pain is bad if I get less than six hours.
There was the 27-year-old woman complaining of numerous problems, all related to her poor sleep. When, eventually, she was monitored in the laboratory, it turned out her sleep was great. “The patient asked, ‘Then why does my Fitbit say I am sleeping poorly?’
“We just saw a variety of patients where it seemed like the devices were making their sleep worse,” Baron says. “They were overly fixated on the devices.”
Baron is not against sleep trackers. She likes sleep trackers. Patients like sleep trackers too, she finds. “People enjoy the wearability, but changing sleep is a lot harder than identifying poor sleep,” she says.
For a minority, however, sleep trackers aren’t helping. “There are still some individuals who are overly intensely monitoring their data, and really determine how they’re going to feel for the day based on what the number says,” she says. “There’s an element of anxiety and trying to hack the best night to gain the advantage. It’s almost like a competition.” She came up with a term for this new condition: orthosomnia.
She is currently formalising an orthosomnia scale, with colleagues in Norway, for use in clinical practice.
Sleep matters. Russell Foster, the director of Oxford University’s Sleep and Circadian Neuroscience Institute, can point to many studies that demonstrate its importance. One of the most telling, for him, is also one of the simplest. It concerns memory. There is lots of research that shows you remember things better if you get a good night’s sleep. This particular study, though, investigated whether the loss of memory was uniform — if it affected every topic similarly. It didn’t.
“The tired brain remembers negative experiences but forgets the positive ones,” Foster says. Everything becomes nastier when you are sleep deprived. “Which may be why there’s such a strong connection to depression and psychosis. One’s whole world view is altered when you’re tired.”
I’m a night owl who gets up early. I get busy at midnight. I used to move the furniture around or do laundry.
He welcomes a population that has woken up to the importance of being awake, that is no longer asleep to the benefits of good sleep. He also understands that, in some ways, we have misunderstood precisely what it is that is important.
“There is a massive amount of anxiety - of unnecessary anxiety. Sleep is a very changeable thing. It changes as we age. It changes depending on what’s going on.”
He recalls giving a talk once. A member of the audience came up to him afterwards complaining that, according to his app, he “didn’t get enough slow-wave sleep”. “He said, ‘I’m quite worried about this. I set the alarm for three o’clock in the morning and wake myself up to check on my app how much slow-wave sleep I’ve had.’ That’s what these damn things can do.
“It should be about embracing the sleep that we get. And we’ve got to stop stressing about it.”
Why, though, do we stress at all? We don’t worry about other essential activities. Why isn’t sleep automatic, like breathing? And was it always like this?
Even when I get home early, which means before 1am, I binge-watch TV. I only sleep three or four hours a night.
We can’t know for certain how we used to sleep. But we can make educated guesses. In the early 2010s, some researchers from the University of California, Los Angeles, visited what is, for anthropologists, the closest thing we have to a time machine.
They went to observe hunter-gatherer tribes, who live like we used to. For 1,165 days, in the savannah of southern Africa, the forests of Bolivia and the bush of east Africa, they collected data. Across three years of campfires and camping out, they logged sleep times and wake times. And they were surprised by what they found.
Contrary to what some had assumed, members of these tribes weren’t going to bed and rising with the sun. They might not have had electric lights or alarm clocks but, like us, they would stay up. Some would chat around the campfire. Others - parents might sympathise - used the time for logistics. Preparing food. Getting arrows ready for the next day’s hunt. Planning.
Between three and four hours after dusk, they were ready for bed. They then spent about 7-8.5 hours in bed and 5.7-7.1 hours asleep. If anything, they slept less than their observers. They also varied a lot. A later, more detailed look at one of the tribes, the Hadza, found that many were what we would call restless sleepers. Some frequently got up in the night, had a smoke, dealt with a crying baby, then returned to bed. There was no evidence they were concerned if they didn’t get their eight hours.
My one key tip is to sleep with my phone at least 5 feet away. That’s helped tremendously. I also do a quick meditation before bed,
This is a preoccupation of Foster’s. He doesn’t like to put a number on sleep. “There is no one optimum duration of sleep,” he says. “Between six hours and ten and a half, or even eleven, can be in the healthy range. And by telling people they’ve got to get seven or eight hours, that can be rather stressful.”
But there was something else of interest that the anthropologists noted, one way in which the sleep of these tribes was not at all like ours: they did not have a word for “insomnia”.
Going to sleep is, on the face of it, a terrible thing for an animal to do. Evolution has created in humans an exquisite organism that can move, sense its environment and protect itself. Then for a third of its life it just incapacitates itself.
While our ancestors in those hunter-gatherer societies slept, they were at risk of attack from animals or enemies. They were vulnerable. They were also not doing anything. They weren’t eating or reproducing. They were just snoring in front of a campfire. This is baffling. Surely any human that had the genes to sleep less would thrive. They would be the ones attacking rather than being attacked, reproducing rather than snoring. Surely natural selection would rapidly select its way out of sleep. Yet it hasn’t. And it hasn’t in any animal we know of. Why do we sleep?
Foster doesn’t think there is any mystery to sleep. We live in a world in which there are, for animals, really two worlds. There is the world of light and the world of dark. These worlds are so different that you can only really optimise for one. Once evolution chooses for you — making you nocturnal or diurnal — then everything else follows. You become active in your chosen world, you become inactive in the one to which you are poorly adapted and then, during that period of inactivity, your body performs all its other essential maintenance functions.
Sleep is like a little time machine - you come out a younger person than before ... That’s what a good night’s sleep can do for you.
Others, including members of his department, disagree. “We haven’t yet found any animal - even insects - that don’t show some sort of sleep state,” says Linus Milinski, part of a group researching the fundamental reasons for sleep. “If you think about it, that’s quite ridiculous.” He simply does not see how this can be explained by light-dark adaptation. “Sleep is so bad, in terms of survivability. You can’t respond to dangers. And, even worse, you can’t reproduce.
“If there were any animals in the past that developed the ability not to need sleep, we should today see loads of those animals.” But we don’t. “In neuroscience, what it comes down to is that we think there must be some sort of repair that goes on during sleep that we really can’t do without — and that for some reason we have to be unconscious for it to take place. We just don’t know why.”
What is sleep? That is an easier question to answer than why we sleep. But only just. It is about molecular biology.
In the office next to Foster’s is his colleague Aarti Jagannath. She studies the genetic and molecular pathways involved in our circadian rhythm, the exquisitely synchronised symphony of chemistry and biology that plays every 24 hours in every human. For our bodies to work we need the right materials, at the correct concentration, delivered to the right tissues and organs at the right time of day.
It begins with the master clock - with “clock genes” in the brain. These genes are the metronome of the body’s circadian symphony. As genes do, they make a protein. The protein has an unusual function. Its job is to stop the gene that made it from producing any others. Once made, the protein prevents more proteins being made. Then it is degraded by other proteins. All this occurs with pretty impressive regularity. It takes, in fact, about 24 hours.
I definitely don’t understand people who sleep 12 hours a day. I see that as the supreme indulgence.
After which, the gene is free to make the protein again and the cycle starts once more.
Those clock proteins in the brain provide the beat of the body. But they are not the symphony. They are more like the conductor. Just as in an orchestra, different instruments come in at different times. “Your body needs to do something completely different during the day versus the night. What we study is: what are the workhorses that actually go off and do all this?” Jagannath says.
There are clock genes in every cell in the body, all controlled by the master clock. For instance, within the long DNA code that determines their particular function, one specific sequence of common genetic code is targeted by the clock proteins. These proteins latch on to this specific code to change what they do by night and by day - regulating the things these genes need to do when we are asleep and the different things they need to do when awake.
But just like in a metronome, the clock genes need to be set. The timing signal is not perfect; it is not exactly 24 hours. It will continue to tick on its own, but left to itself will slowly drift away from the true time and the cycle of light and dark. If you put people in a cave, without access to any natural cues, you find that the clock genes are generally a little slow, taking longer than 24 hours to tick. People will get up a bit later and later each day.
So the master clock needs outside information. There are many cues that the brain integrates to tell us when to sleep and wake. When you eat, when you exercise, when you are stressed (about, for instance, not falling asleep) - all this can influence our 24-hour timing. Important also is simply the length of time we have been awake. When we are conscious, key chemical signals build up in the brain that drive sleepiness, and when we sleep the concentration of these chemicals drops dramatically. Caffeine in coffee blocks one of the receptors that detects these chemicals, which is why, temporarily, it makes you feel less sleepy.
But there is one cue that is most important of all - the key signal that “sets” our biological clock. If the circadian rhythm is indeed a symphony, this cue is the loudest instrument of all: the circadian equivalent of the cannon in the 1812 Overture.s
I am an insomniac. I wake up so early and hope the New York Times has posted its next crossword puzzle.
There are receptors in our eyes that differ from the ones you know from school - the rods and the cones. The rods and cones help us form images. But these other receptors simply measure brightness. They see the dawn and the dusk and set our clocks. Russell Foster was the scientist who did the pioneering work to identify these sensors in the eye.
To see why the sun, or its absence, could explain our current maladies, you could do worse than look in Jagannath’s office. Her window looks out onto a basement without windows. Foster’s work in identifying photoreceptors in the eye gained him the Daylight Award, a prize awarded to both architects and scientists who work on light. His department, though - and they appreciate the irony - has almost no natural light.
They have tried to brighten it up with houseplants, Jagannath says. They failed. “The plants keep dying, which is quite depressing as well.”
When sleep goes wrong, it is because the orchestra isn’t playing at the right time. Maybe the trumpet is being a prima donna and playing its own solo. Instead of a symphony, you get a cacophony.
Sometimes, there are medical reasons for this circadian cacophony. The most extreme - and least resolvable - is total blindness, which means that the brain cannot receive the signals that tell it is day or night. These people are time blind. They live in a world of endless jet lag.
Kyle knows how complex sleep is. But you don’t need to untangle its complexity to fix it. A lot of the time, all we need to do is make everyone pay attention to the conductor.
When he treats patients, Kyle begins by preventing them from sleeping. He tells these patients - all desperate for eight hours, striving for the sleep equivalent of five-a-day - that he will only allow them, say, five and a half hours.
I’ll wake up at four in the morning. My internal clock just clicks and I’m up.
During that allotted period they sleep - exhausted. And they learn something. “We expose them to the ultimate feared outcome, which is less time in bed.” The next day, they are sleep-deprived but they get through it. And as a reward they are allowed a little more sleep, then a little more the day after. Gradually they approach a full night’s sleep.
“People learn that not only do they experience deeper, consolidated sleep, but also that they can function with a limited time in bed. That challenges some of their beliefs.” In this way, he deals first with the worry, then allows the sleep to follow.
Here, then, is the sleep paradox. If you teach people not to fear being awake, if you teach them to let go of their urge to sleep, they are more likely to catch that sleep. Sleep is really important and getting it right will make you happier, healthier and probably more successful. But you really shouldn’t worry about it. Because that could well make it worse.
Now you just have to learn how to reconcile those thoughts as you lie awake beneath your weighted duvet and watch the bedside clock tick over once more to 4am.
Written by: Tom Whipple
© The Times of London