From fitness trackers to smart speakers, the Internet of Things has permeated all aspects of our lives – including our sleep.
The marketing tells us sleep trackers help us monitor our sleep. Is that true, or is it possible sleep tracking is actually bad for us?
Ultimately, whether or not sleep tracking is bad for your health depends on how you use these devices. Keep reading to learn more.
What are sleep trackers?
Sleep trackers help you track your sleep. You can find them as standalone sleep tracking smartphone apps, or as one of the features included in your fitness tracker or smartwatch.
In their most basic form, sleep trackers tell you two things: how long you’ve slept and the quality of your sleep (i.e. whether you woke up during the night at all). Some sleep trackers also offer listening capabilities, monitoring your sleep for sounds of snoring or sleep apnea, and some claim to tell you how much time you spent in various stages of sleep, light or deep.
If you’re using a sleep tracking app, you let the phone sleep by you in bed. If the sleep tracking is part of your personal fitness tracker, you simply keep wearing that device as normal when you go to bed.
Then, when you wake up in the morning, you take a look at the tracker to see what helpful information it has to reveal.
How are these devices able to share the information they claim? Sleep trackers use the accelerometer in your smartphone, smartwatch, or wearable device. Accelerometers monitor your movement. If you stop moving, it’s likely you’re asleep. When you wake up in the morning and move around, your accelerometer senses that and knows that you’re awake.
This seems straightforward enough. What does the science have to say?
What the science says about sleep tracking
Unfortunately, time and again, studies show that there is “a critical absence of supporting evidence for the advertised functions and benefits in the majority of the devices.”
The distinction in movement between sleep and wake is pretty clear. Several studies have shown sleep trackers are fairly accurate when it comes to measuring your total wake time. A 2015 study favorably compared the Jawbone UP with polysomnography, for instance.
Things start to get fuzzy when sleep trackers claim to distinguish between the stages of sleep. Our bodies make similar movements in light and deep sleep. For example, our bodies are paralyzed during REM sleep (in order to prevent us from acting out our dreams), but we may twitch and confuse especially sensitive trackers into thinking we’re awake when we’re deep asleep. We also naturally move some during sleep, shifting positions a few times during the night to avoid our muscles from going numb.
The best way to distinguish between the various stages of sleep is by observing your brainwaves, not movement. In a sleep lab, sleep technicians will look at your brainwaves, along with other vital functions, such as your breathing, heart rate, body and eye movement, and oxygen levels, to monitor your sleep and diagnose a sleep disorder. It’s not that accelerometry is inaccurate. It’s just that it doesn’t provide the full picture.
The other issue with the reliability of sleep tracking devices is just that – they’re not reliable. There’s large variability among what different devices view as awake vs. asleep. While the 2015 study cited above found a Jawbone to be good at measuring total awake time, a study of a Fitbit Ultra found that it over- or underestimated sleep, depending on the individual user, and yet another study of Fitbit found that it overestimated sleep time for all participants.
Sleep tracking, anxiety, and orthorexia
While the claims of identifying different sleep stages are unsubstantiated, sleep tracking can certainly help you get a better idea of how much sleep you’re getting. Because the tracking in these devices is often automatic, there’s less chance for human error or forgetfulness.
Sleep tracking helps you pay better attention to your sleep health. However, that extra attention can come with extra anxiety. For some people, once they start monitoring their sleep, they become more prone to overanalyzing it, worrying that they are not sleeping enough or that they’re sleeping too much.
When you consider the likelihood that the device is not even fully accurate in regards to measuring your sleep, this opportunity for “clock-watching syndrome” is a real problem. People become obsessed with achieving “correct sleep,” technically known as “orthosomnia.”
Researchers from Rush University are calling this phenomenon “orthorexia.” Just as anorexics become unhealthily fixated on their eating habits, orthosomniacs develop an obsession around their sleep. They obsess over the data, and begin to self-diagnose sleep disorders based solely on what the sleep tracker tells them. In fact, they may become so stressed out over the data that they lie awake at night worry about it, developing insomnia that they didn’t have in the first place. Then, when they bring their concerns to a qualified sleep doctor, they refuse to believe the results of a polysomnogram as valid they disagree with what the sleep tracker says.
The study authors advised that clinicians have to be thoughtful about educating patients about the accuracy of these devices, how to use them properly and what to reasonably expect from their data. Fortunately, by reading this article, you’re already educating yourself!
Even if you don’t develop full-blown orthorexia, your sleep tracker can still interfere with your thoughts around sleep. For example, if your sleep tracker says you’re not getting enough sleep, you may start to believe it and fall into a spiral of catastrophic thinking. How we view or judge our sleep has a big impact on how well we actually end up sleeping, according to a 2014 study.
The study authors split participants into two groups. Both were educated about the importance of REM sleep and how much we need each night. Then the participants were told that the researchers could measure their REM from the night before (although that isn’t true; doctors have to examine your brainwaves while you sleep to be able to detect when you are in REM).
After the researchers “measured” everyone’s REM, they told one group that they got enough REM and the other group that they didn’t. The students who were told they got insufficient REM then performed worse on tasks that assessed their daytime functioning (the PASAT measure in the chart below). Researchers noted they reacted the way one would after a night of sleep deprivation – regardless of whether or not they did get enough sleep.
Finally, there’s one last argument to be made against sleep trackers. Many of us already have a hard enough time shutting our phones off at night. If you take your phone to bed with you to track your sleep, you may be less inclined to turn it off.
And technology interferes with sleep, sleep tracker or not. Our brains perceive the blue light in smartphones and other tech devices more strongly than any other wavelength. In fact, when your brain encounters this kind of blue light, it thinks it’s seeing sunlight, jolting it into alertness and energy – even if it’s late at night and you’re laying in bed trying to fall asleep.
Is sleep tracking bad for YOUR health?
As we’ve mentioned above, if your sleep tracker helps you stick to a sleep schedule and get more sleep, that’s fantastic.
However, if you finding yourself starting to fixate on the data, it might be time to stop using it for a while. Reset your perception of the sleep tracker’s power. This is just another tool in your toolset for living a healthier life, and it’s no longer doing its job if it’s giving you stress and anxiety.
If you’re worried you have a sleep disorder, ask yourself the following questions:
- Do you have negative, obsessive, or otherwise unhealthy thoughts about sleep tracking?
- Do you believe you’re getting fewer than 7 hours of sleep per night?
- Are you excessively tired upon waking up, with fatigue or lethargy that persists throughout the day?
- When you get into bed at night, does it take you longer than 30 minutes to fall asleep?
If you answered yes to one or more of these questions, it may be worth seeing a doctor. The answer could be innocent, such as not following good sleep hygiene (a few behavioral changes can turn that around), or you may in fact have a sleep disorder. Either way, your doctor can help you figure it out and provide further diagnosis.