On our quest to find good sleep that leaves us ready to face the day, a lot of us have turned to data — not in the form of a spreadsheet, but from a sleep tracker. Sleep trackers are designed to give us useful feedback about how we’re sleeping so we can make adjustments that will hopefully help us Unjunk our Sleep. There are many ways to track how well (or how terribly) we’re sleeping at night, including wearables like watches, chest monitors, or rings, as well as apps that use sonar.
If you’re wondering how best to start tracking your sleep, it’s wise to understand how sleep trackers work, what features are most useful, and which type will work best with your sleeping style.
What does a sleep tracker do?
To get all the details on sleep trackers, we checked in with sleep neurologist and Sleep.com Sleep Advisor Dr. Chris Winter, who explains that the initial way at-home trackers worked was by detecting movements through an actigraphy device worn at night. While such devices can help uncover certain sleep issues, Winter says they don’t always provide a complete or accurate picture of sleep.
Most of our sleep trackers today still use movement as one indicator of how well you’re sleeping, but they also incorporate several more metrics to become polysomic devices, which simply means they’re tracking many aspects of what’s going on while you sleep.
The more measurements, the more in-depth look you’ll get. Winter likens the breadth of sleep information to a game of “Guess the Animal.” If the first clue is “This animal is gray,” that leaves the number of possible options incredibly broad. If the next clue is “This animal is large,” that helps narrow down the field of possible answers. By the time you get to “This animal has tusks,” you’re left with just a few options.
Tracking sleep accurately means using a similar narrowing-down process. Measuring movement can provide a helpful data point, but is of limited value by itself —if you sleep with a pet, for example, the dog jumping off the bed to grab some midnight kibble could muddle an otherwise clear view of how your night went. However, if a tracker is also measuring your pulse, breathing, and heart rate variability, then that sudden motion by the dog is less likely to muddle the overall accuracy of your sleep data.
“When you keep adding variables, the precision gets a whole lot better,” Winter says. Tracking more variables can lead to a more comprehensive view of how well you’re sleeping or help to pinpoint why you’re not sleeping well.
Data from a sleep tracker could help you uncover what leads to a good night's sleep. If your sleep data indicates you slept poorly last night, it could help pinpoint habits that are not conducive to great sleep, like that post-dinner espresso. Used in conjunction with a sleep diary, a tracker could help you craft the perfect recipe for which foods, drinks, levels of activity, or bedtime routines are most likely to lead to a night of restorative sleep.
Which type of sleep tracker is right for you?
Most sleep-tracking devices can be separated into two types: wearable and non-wearable. Each has its own set of pros and cons. Which kind of device will suit you best depends on your personal preferences, your sleep style, and whether you sleep alone or share your bed with a partner or pets. Here’s how to choose the right sleep tracker to get the best insight into the quality and composition of your sleep.
Wearable sleep trackers
It’s possible that you already own a sleep tracker. Many fitness watches from well-known companies like Fitbit, Garmin, and Apple can track your sleep. These wristband trackers often work by sensing your movement, pulse, heart rate variability, and breathing, and some can even measure oxygen saturation by serving as a pulse oximeter.
One potential drawback Winter notes about using a watch for a sleep tracker is that you have to track battery life and schedule time to recharge the watch. “The big problem with some watches is you might have to charge the device almost every day, and if you're wearing it during the day, you're probably charging it at night,” he says. In addition, some people simply don’t enjoy the feeling of wearing a watch to bed, and restless sleepers could find it getting caught on sheets or blankets. Still, it could be one of the more convenient ways to track your sleep.
The WHOOP is a popular wrist option that can monitor sleep, activity, and even menstrual cycles.
Other wearable sleep trackers monitor similar variables as a wristband smartwatch, but in a ring form. For example, the Oura Ring not only tracks sleeping at night but can also detect napping, as well your body temperature — something not all smartwatches do. The ring design could work well for sleepers who are uncomfortable wearing a watch to bed.
Headbands like the Philips SmartSleepDeep Sleep Headband are another option in the category of wearable sleep trackers.. Not only does the Philips headband track sleep, but it’s also designed to play quiet audio tones that could help you get a better night’s rest.
Non-wearable sleep trackers
For anyone not interested in wearing a wristband, ring, or headband to bed, it’s possible to track sleep effectively using a non-wearable device. That device could be the bed itself, something that sits on your bedside table (like your phone), or even the bed’s base.
Smart mattresses and mattress bases can track sleep by monitoring your motion, temperature, and heart rate. Some even provide a printout of tracked data, should you decide to discuss the results with a doctor. With an attached microphone, some smart adjustable bases can detect snoring and even change the bed’s position into one that helps minimize snoring.
There’s also the option of a sleep tracking mat that sits under your mattress to monitor movement, heart rate, and sleep sounds. Winter says this is especially useful when used in tandem with a wearable sleep tracker, as the combination could make for a fairly accurate picture of sleep quality. It’s unlikely, however, that anyone would travel with a sleep tracking mat, so this choice might not be the most consistent tracker for those who aren't home much.
The Sleep.com app use sonar technology to measure movement and breathing while you sleep to formulate a SleepScore and gauge your time in different stages of sleep. With your phone placed on a bedside table, the app uses your phone’s speaker and microphone to send and receive soundwaves. This sleep tracker’s technology can weed out data from pets or a restless partner since the app will only be tracking the body that’s physically closest to the phone.
Are sleep trackers better than an overnight sleep study?
The gold standard of tracking sleep is typically an overnight sleep study in a lab. Using electrodes attached to your body, a medically verified in-lab sleep study takes in-depth measurements of brain activity, eye movement, muscle activity, breathing, and blood oxygen levels, among other metrics. In a top-tier lab, that equipment will be properly calibrated for accuracy beyond what a home device can offer. But Winter cautions that an overnight sleep study isn’t always the best way to determine how well you’re sleeping. In fact, it might not be the right choice at all. For one thing, data from a single night of sleep cannot indicate ongoing patterns and habits; for another, many people need a few nights to adjust to a new sleep setting (such as an unfamiliar lab).
Instead, Winter notes that a sleep tracker worn every night gives a great long-term look at sleep patterns that could provide a better picture overall of how sleep is going and what causes a night of poor sleep.
“The real strength of the wearable and non-wearable tracker you can use at home is that although you’re maybe not getting the depth of information that you would get with, say, an in-lab sleep study in Stanford University, you are getting a longitudinal look at sleep that the single-night sleep study really can't match,” Winter says.
Should you be using a sleep tracker?
If you’re curious about the quality or duration of sleep you’re getting, you might enjoy seeing the data points a sleep tracker offers. As Winter points out, an at-home sleep tracker provides a longer-term look at how you’re sleeping, and the more variables a sleep tracker monitors, the better picture you’ll get.
You might already own a fitness tracker or watch that can track sleep. Alternatively, some sleep trackers, like the Sleep.com app, come in a free version, so you can start to gain insights into your sleep right away.