The other day, I was plodding away on the treadmill at the gym when I overheard two blokes chatting.
“I had a great night last night,” said one.
My ears pricked up. A juicy story?
“Scored 96.”
I yawned.
“That’s insane,” his companion gasped. “My average is 67 and I can’t seem to get it much higher.”
“Ah, but how’s your HRV?”
“Never check that, but I know my REM score’s been all over the place this week.”
It was only the mention of REM, AKA rapid eye movement, that made me realise they were comparing notes on their sleep performance.
Welcome to the world of orthosomnia, the medical term for an unhealthy obsession with attaining perfect sleep, usually driven by a wearable device. The term was coined by US researchers in a study published in the Journal of Clinical Sleep Medicine, which showed that, ironically, geeking out over your nightly sleep data may actually make your insomnia worse. The scientists observed how some people spent excessive time in bed trying to perfect their score, while others experienced anxiety about not achieving a good enough sleep performance.
But what constitutes “a great sleep score”? And is it even possible to hack an involuntary biological process?
Katie Fischer, a behavioural sleep therapist, says that many of her clients are chasing the “perfect” night’s sleep. “The thing is, if you ask good sleepers what they do, they will usually say ‘nothing’,” she says. “They’re not thinking about sleep. They’re tired, go to bed and drift off. They wake up feeling refreshed and don’t worry about the occasional bad night because they know that happens sometimes. Meanwhile, people who come to me with problems are often putting pressure on themselves to attain a magic number of sleep hours, typically eight, without understanding that they might not need that much.”
She has seen clients distraught because their trackers have recorded only 11% deep sleep a night. “I tell them that’s pretty normal. We sleep in cycles of roughly 90 minutes and we transition between light, deep and REM phases. For most people, deep sleep will only account for 13-23% of the night. Time awake is also a normal part of sleep. We can have between three and six rousings a night; often we’re not even aware of them. Most people have no idea what normal sleep looks like, so they panic when they see stats with lots of awakenings and not much deep sleep.”
Someone who knows first-hand about crunching sleep numbers is Ollie Matthews, a functional medicine practitioner and health coach. He has experimented with most leading device brands including Samsung and Apple Watches. Currently he uses an Oura Gen3 smart ring and cross-references it with his Garmin Connect, which he bought for running but which handily also has a sleep tracker.
“The way I’ve used these has changed over the years, mostly because I’ve seen how my own clients can become a bit obsessed with them, as I was myself,” he says. “It used to be that the first thing I would do when I woke up was check my data, and sync it to my other devices, without actually checking in with my own body. I would panic if my ‘readiness’ score was low or my sleep score had dipped.”
On his Garmin tracker there is a “body battery’” indicator that logs the user’s level of “charge”, based on their stress level (measured by HRV, which stands for heart rate variability), how much rest they have had, their sleep score and, for some people, body temperature. “I’ve managed not to be as obsessed with it now,” says Matthews. “I used to look at it when I was falling asleep, to track my sleep latency [how quickly you’re getting into sleep state]. And I wouldn’t listen to the helpful messages it was sending me, such as: don’t train at the gym when my sleep scores were low. I suppose the appeal of these is that you can gamify your own health, and your entire life.”
It may sound overzealous to be cross-referencing two devices, but Matthews says this is purely because since he upgraded to the latest Oura ring, it seems to be picking up on his wife’s movements much more than the previous one. “I’ve resolved it by us sleeping in separate beds – though, to be fair, she is pregnant, so it’s not just about the sleep tracking.”
In 2007, in San Francisco, the Wired editors Gary Wolf and Kevin Kelly coined the term “quantified self” when describing the concept of “self-knowledge through numbers”. Now, this ever-growing trend for self-scrutiny has spread to the quest for optimal sleep. Against a backdrop of apps, books and podcasts hosted by sleep geeks, the UK industry for sleep trackers was estimated at £270m last year and is forecast to more than double by 2030.
As someone who once went through a terrible year of insomnia during a stressful life episode, I haven’t dared to use one. It would stress me out to have a nightly critique of my sleep quality. But I am curious. What are these devices actually measuring in order to come up with all this data?
Dr Neil Stanley, the author of How to Sleep Well, has been working in the field of sleep research for 42 years, starting out at the neurosciences division of the RAF. He sighs when I ask him to explain how most devices analyse our shuteye. “These things can just about measure how much sleep you’ve had, and how long it took you to get there,” he says. “But the only accurate way of distinguishing between light sleep, deep sleep and REM sleep is by observing the brain.” He mentions that while one study showed that sleep trackers are now “reasonably accurate”, some of the claims made are questionable.
But Stanley also wants to raise a more fundamental question. “I’ve spent my career hooking people up to monitors in spaces designed to be the finest bedrooms on the planet. I’ve sat there watching the squiggly lines that measure the different stages of sleep. And, to be honest, it doesn’t mean a thing. Because what even the most accurate data cannot do is influence you to sleep more hours. So, for the general public, what’s the point?”
He also says that if there is one night when someone misses out on the sleep they need, the body will usually rebound to catch up the night after. “I’m not saying that you can’t improve the quality of your sleep; there are lots of things you can do. I would recommend anyone to keep a pen-and-paper sleep diary of what time they go to bed, how tired they feel, when they wake up and how awake they feel at 11am. In other words – listen to your body, not data.”
Fischer agrees. “Perfect sleep doesn’t really exist. There’s no foolproof recipe, and micromanaging data only creates stress. What matters is: how do you feel? Do you have enough energy to get through the day and feel as if you’re functioning well with a good quality of life? The best way to keep tabs on it is to look at patterns over a week or two rather than obsessing over one or two individual nights. You want to check that you’re feeling well rested at least four nights a week without having spells of being awake for longer than 30 minutes.”
Prof Guy Leschziner, the author of The Secret World of Sleep and a consultant at Guy’s and St Thomas’ hospitals in London, also questions the usefulness of sleep tracking. “There are some intrinsic differences between tracking sleep and tracking exercise. If a Fitbit tells you that you’ve only done 2,000 steps, it’s not that difficult to up your count. But being told that you are not sleeping enough hours or deeply enough isn’t actionable,” he says.
“The magic way of getting a good’s night sleep is to recognise what the obstacles are. Are you sleep deprived because there aren’t enough hours in your day? Or is it that you can’t fall asleep in the first place? Or do you get enough hours but find yourself still feeling sleepy during the day (a possible sign of a sleep disorder)? On the basis of that information, you can seek help.”
He is of the opinion that any data about REM sleep, associated with dreaming, emotional processing and memory consolidation, is meaningless. “We don’t know how to interpret those numbers. We do know that REM sleep serves an important function, but in the past, when certain antidepressants suppressed REM sleep altogether, people didn’t suffer any consequences.
“The other issue is that even the most accurate devices have not been validated in people who suffer from abnormal sleep. So if you suffer from insomnia or sleep apnoea, your device is likely to be less accurate.” The new Apple Watch 10 gives sleep apnoea notifications – is this not useful? “In theory, yes. We know that 80% to 90% of people with the sleep breathing disorder don’t know they are suffering from it. But it’s only just been released, so any claims of accuracy would need to be properly evaluated.”
Leschziner believes there is one group who can definitely benefit from sleep tracking: those who have been burning the candle at both ends and have lost track of how much sleep they are getting – or losing. Schuggie Macinnes falls into this category. He runs a business as a “ceilidh caller”, hosting Scottish events at weddings and clubs across the Midlands. But during quieter times he also works as a payroll manager for a housing association. And he’s a father, who likes to keep fit. “My sleep patterns are erratic,” he says. “Some nights I might be in bed at 9pm and sleep in until 10am. Other days, I’ll be up at 4.50am to get to the gym, then drive to work. Then if I’ve got a ceilidh, I won’t be home until 2am. My son plays football so I have to get up early the next day. I wear a Whoop band and eventually it gave up on telling me how much sleep debt I had. It was off the scale.”
Far from getting stressed by the numbers though, Macinnes believes monitoring how much sleep he is getting is really helpful. “It’s very hard for me to keep track otherwise. So I’ll know when it’s a good idea to try to prioritise more sleep. It’s also helpful to see how what I do in the run up to going to bed – eating late, having a drink – impacts the quality of my sleep.”
But there are some life circumstances where monitoring sleep data is of no use whatsoever. Leila Green, an entrepreneur, was a keen runner who used a Garmin watch to log her times. As it had an inbuilt sleep tracker, she began to make use of that too. “I really liked it. I’d wake up each morning intrigued. How did I do? It was fun.”
That all changed when Leila gave birth to triplets. “On a bad night, I wouldn’t get more than four hours, and that would be broken. In the morning, my watch would send me super unhelpful comments like ‘you may find you are more tired than usual today’. It began to feel like the watch was telling me off. It just wound me up. And I felt like a sleep failure. My other problem with sleep data is it’s something that happened in the past so you can’t do anything about it. I’m desperate for coffee, the kids are screaming; the last thing I needed was a negative review of the night before.”
However, now that her sons are at nursery, Leila has gone back to wearing her tracker. “It made sense to start using it again because I wanted to improve my exercise and sleep and get on top of things. And even if I feel like I’ve had a terrible night, sometimes I might look at my score in the morning and it’s giving me 90%. It’s psychosomatic, I guess. My watch has told me I’ve had a great night’s sleep so I can’t really be tired can I? I will get on with my day feeling like I’ve been awarded a gold star.”
Where will it all end? A recent article published by Loughborough University on the future of sleep tech mooted concepts including pyjamas embedded with sensors to track changes to posture, breathing and heart rate, and hugging a robot pillow coded with a respiratory pattern to help people get to the land of nod more quickly. It’s enough to make you want to go and lie down.
