image of sleep tracker on wrist

Losing Sleep Over Sleep Trackers

Every time we turn around, it seems, companies are releasing new sleep tech products that claim to use cutting-edge scientific research to improve the quality and quantity of our rest. We know that these tracking devices, apps, and other gadgets don’t always live up to the hype, but now it turns out they could they be creating entirely new problems too.

In an article published in the current issue of the Journal of Clinical Sleep Medicine, Dr. Kelly Glazer Baron of Rush University Medical School suggests that sleep trackers have given rise to a new phenomenon: orthosomnia (from “orthos,” meaning correct, and “somnus,” meaning sleep), an obsession with tracking and optimizing sleep. The fixation is often exacerbated by anxiety about recording the “perfect” night’s sleep, to the point of creating a sleep disorder where one may not exist.

Orthosomnia and quantified sleep

It’s easy to see how we got here. Baron and her co-authors begin by noting that 10% of U.S. adults use fitness trackers and that more and more people are relying on them for sleep data. As a result, users can get stressed if they notice something amiss with their stats.

The problem is that when it comes to measuring sleep, mass-market trackers are unsophisticated and inaccurate compared with medical-grade devices. Even so, people are inclined to listen to their Fitbits and Apple Watches—sometimes even more than to their own doctors. “To the patients,” the authors write, “sleep tracker data often feels more consistent with their experience of sleep than validated techniques, such as polysomnography or actigraphy.”

By way of example, the article offers three case studies of medical patients whose fixation on sleep data caused complications for their treatment. In one case, a 27-year old woman went through a battery of tests, all of which showed no identifiable sleep disorders. “Despite hearing that she slept deeply on the in-laboratory polysomnogram, the patient asked, “Then why does my Fitbit say I am sleeping poorly?” Even after seeing the objective test results, the researchers write, “patients’ beliefs about the sleep tracker data were unchanged.”

The limitations of fitness trackers

While fitness trackers are great at counting steps or measuring the distance of a run, they are less reliable when it comes to producing meaningful sleep data. The authors point to “multiple validation studies that have demonstrated consumer-wearable sleep tracking devices are unable to accurately discriminate stages of sleep and have poor accuracy in detecting wake after sleep onset.”

That’s because most sleep trackers use only an accelerometer and some software to determine whether you are asleep or awake, and this sensor relies entirely on movement. A tracker might think you’re asleep even if you’re simply lying in bed, staring at your phone. Some trackers claim to be able to distinguish between stages of sleep based on how much we move. While it’s true that bodies move at different rates in each stage of sleep, we need to monitor several other factors, including dominant brain waves, in order to identify sleep stages with certainty. Currently, the only way to do this is with complex medical testing methods such as polysomnography.

Finally, fitness trackers tend to display their data without context or explanation, which can be another source of anxiety. You might see, for example, that you’re getting a certain amount of REM vs. non-REM sleep without knowing what those terms mean or how much of each is considered normal. One subject of the study was convinced, based on her Fitbit data, that she wasn’t getting enough deep sleep, despite being shown a detailed set of test results indicating that, in fact, she was getting more than the average for her age group. Deep sleep is highly sought after because of its restorative properties—but it’s also only one part of our sleep cycle. Even on a good night, we might spend just a fraction of our time in deep sleep, so we shouldn’t fret too much if we see tracker data that indicates as much.

Using sleep data for good

Although many sleep doctors are skeptical of fitness trackers, they also realize that consumers are becoming more and more attached to such products, and in “the quantified self” more broadly. Dr. Baron and her team end their article by mapping out a potential future for the integration of sleep trackers into regular courses of treatment.

“The challenge for clinicians,” they write, “is balancing educating patients on the validity of these devices with patients’ enthusiasm for objective data.” Rather than relying solely on trackers, the data can be just one part of more holistic approach to sleep health: “Working with patients to integrate devices into treatment provides the opportunity to increase communication between patients and providers and reduce participant burden.” That way, providers can encourage their patients to keep track of sleep enthusiastically but not obsessively.

Above all, don’t let a fondness for technology hold sway over your sleep. If you have problems with fatigue or insomnia and your tracker backs it up, then talk to your doctor. But if that wristband or phone app or smart pillow is just causing you anxiety, switch it off and look for more traditional methods of winding down.