The rise of the sleep data nerds: ‘The harder you try, the harder it is to sleep’ | Sleep

TThe first thing Annie and her partner do when they wake up in the morning is ask each other how well they slept. “And I literally say, 'I'm not sure yet, let me check,'” and Annie, the HR and security director, reaches for her smartwatch.

Annie started monitoring because she was worried she wasn't getting enough quality sleep. She's now a self-confessed sleep data nerd, collecting her sleep data to gain insight into her overall health and well-being, using it to make lifestyle decisions and even sometimes to determine how much she aims to accomplish in a day.

Sleep monitoring is a rapidly growing industry, reflecting what devices and apps like Fitbits and Strava have done for physical activity. Market reports vary on the value of this industry, but it is clearly profitable and growing rapidly. A quick search turns up a wide range of devices—rings, headbands, watches and other devices worn on wrists, under-mattress devices, and bedside devices—all of which suggest that their use will provide the kind of quality sleep that would make Rip Van Winkle jealous.

Estimated 40% of Australians do not get enough quality sleep, and one in ten suffer from chronic insomnia.. “We know there are a lot of people who are worried about their sleep and whether they're getting enough sleep, especially if they're not meeting some of the recommended sleep duration guidelines,” says Dr Hannah Scott, a senior research fellow in sleep psychology at the Flinders Institute of Health and Health Research in Adelaide and co-creator of a wearable device that monitors and treats chronic insomnia.

Scott says the rise in sleep tracker use is generally good news. “They've certainly raised awareness of the importance of sleep and healthy sleep patterns, so overall I'd say they've probably had a positive effect.” But there is also a downside. “If you try harder to exercise, you'll get better, but we actually have the opposite problem with sleep: the harder you try, the harder it is to actually fall asleep,” Scott says. “We may be causing some problems because people are too obsessed with trying to optimize it.” There's even a term for this: orthosomniawhich describes an unhealthy preoccupation with sleep tracking data.

The most accurate picture of sleep health is provided by something called polysomnography, in which a person spends the night in a sleep laboratory with their head and body covered by electrodes that monitor and measure brain wave activity, eye movements, breathing, heart rate, muscle movements and blood oxygen levels. This provides a wealth of information, such as time spent in different stages of sleep, how many times a person wakes up and how long it takes them to fall asleep, says Professor Christopher Gordon, professor of sleep health at Macquarie University in Sydney.

“Wearable devices—and this puts a lot of different devices into one word—but they generally aren't accurate enough to tell you how long it took you to fall asleep and how long you were awake and asleep at night, and that's because they don't measure brain wave activity,” he says. This brain wave activity is used to determine the time spent in different stages of sleep: stages 1, 2, and 3 of NREM sleep and REM sleep.

Wearable devices can detect and measure—in various combinations and with varying degrees of accuracy—heart rate, temperature, movement and blood oxygen levels, which are then fed into algorithms that determine whether the picture painted by that data represents a person fast asleep or restlessly awake. “It could be a device that specifically measures only movement and looks at algorithms that say if your arms move a lot, you're awake, if they don't move a lot, then you're asleep,” Gordon says. But “this has very little consistency with what's going on in your brain in terms of the quality aspect of sleep.”

Another problem is that there is no clear understanding of what exactly good sleep looks like, says Associate Professor Jen Walsh, director of the Center for Sleep Science at the University of Western Australia in Perth. “This is a topic that is discussed in our profession,” she says. There's sleep quantity—simply the amount of time spent sleeping—and sleep quality, which is more complex and takes into account time spent in different stages of sleep, whether sleep is disturbed, how often, and for how long. “Amount of sleep is fairly easy to determine and calculate, whereas quality of sleep is a little more difficult,” she says. Current recommendations suggest that adults should aim for seven to nine hours of sleep per night, but there are no clear recommendations on what type of sleep—how ​​long each stage—is optimal.

According to Dr Maya Shenker, postdoctoral fellow in trauma and sleep at the University of Melbourne, sleep quality is also very subjective and sometimes doesn't match what even the most accurate laboratory monitoring shows. “If we feel like we haven't slept well, it doesn't matter what the clock tells me,” she says. Even for people with chronic insomnia, sleep often looks much better on polysomnography than what they report subjectively.

Consumer sleep trackers have one advantage over polysomnography for sleep research: they are used every night for an extended period of time. “One night in a sleep lab gives you just one snapshot of that night, but it's not necessarily a reflection of every night while you're at home in your own bed without wires tied to you,” Walsh says.

Rachel says her sleep monitoring ring has helped her understand some of the factors that help her sleep better at night. “If I do Pilates in the evening, I seem to sleep better,” says the Canberra civil servant. And Annie noticed that if she drank a glass of wine at any time in the evening, her heart rate increased by about 10% during sleep.

This is where most experts see the usefulness of sleep trackers for consumers: helping people understand how their lifestyle and behavior affects their sleep and making changes to improve it.

“Many people are interested in changing their sleep habits, but it's hard to know where to start,” says Dr Vanessa Hill, a sleep specialist at the Appleton Institute at CQ University in Adelaide, who also consults for Samsung Health. Typically, data alone isn't enough to change behavior, but “if your watch can send you a notification like, 'Hey, you were out at this time yesterday and that made you sleep better,' or 'You stopped drinking caffeine around this time yesterday,' or whatever, and it helps you fall asleep faster,” that could motivate people to change, she says: “I think that's the best potential that trackers like this could have.”

Hill uses a smartwatch and ring to track her sleep and says she checks her sleep metrics, especially her heart rate while she sleeps, which she talks about. can predict an approaching illness – as soon as she wakes up. “I look at what they were doing at night because if I get sick or have a cold or something, my heart rate variability will tell me that before I feel any symptoms myself,” she says. “If for some reason one night my heart rate variability really changes a lot, I'll just say, I need to relax today, there's something wrong with my body.”

Many experts emphasize that consumer sleep trackers are not diagnostic tools and have some important limitations. “If you train an algorithm on a healthy population, you won't necessarily get the same signal from a population with, say, peripheral vascular disease and reduced blood flow to the fingers,” says Dr Donald Lee, a sleep respiratory therapist at the Woolcock Institute of Medical Research in Sydney. Sleep habits also change throughout life, which may not be reflected by the algorithms used.

However, Lee says sleep trackers do offer an opportunity to encourage healthier sleep habits. “If we can encourage people … to go to bed with a purpose, to turn off the lights and go to bed, and improve their sleep habits by engaging in conversation, that will be useful for health monitoring researchers.”