How to (really) use a sleep tracker

Technically, you don't need a PhD to tell you how to work these, but we found one anyway.

When it comes to sleep, we're a nation in flux. At the same time we're in the midst of a sleep epidemic, cultural tastemakers from Arianna Huffington to NFL athletes are calling it a panacea. Basically, if you're not getting enough sleep, you're not performing up to your full potential. Enter sleep trackers. Once the purview of sleep labs, mass market options now include dozens of apps, health and activity trackers and devices devoted solely to sleep. But navigating the sleep technology landscape isn't so straightforward. We went to the experts to find out the upsides and downfalls of tracking your zzzz's.

let's get technical

First, a primer on how sleep trackers work. Whether you wear something on your your wrist (such as a Jawbone UP), or it’s part of your bedding (like the pillow clip Sense by Hello uses), it’s using an accelerometer to collect data. That data is fed into an algorithm which interprets movement patterns to figure out if you’re snoozing. “In general, when we’re awake, we move a lot and when we’re asleep we move a little,” says Jennifer Martin, PhD, a clinical psychologist and sleep specialist in Los Angeles. “If you’re perfectly still for two minutes, but you’re moving around before and after, you’re probably not asleep. The algorithm incorporates the information in the minutes before and after––the art is in how much weight you give the adjacent minutes.”

the accuracy dilemma

There are two ways a device can excel or fall short: collecting data and interpreting it. Martin provides this anecdote: Two of her colleagues used the same make and model wearable for a few nights. The device said one person’s sleep was very good and the other’s was poor. When they swapped devices, the person who previously had poor sleep suddenly slept soundly and vice-versa. Mass market trackers just aren’t as accurate as the $500 to $1,500, FDA-approved, medical-grade technology used in labs. As for the algorithms, they’re intellectual property so companies aren’t keen on sharing them (which can make it hard for sleep researchers to confirm accuracy). So keep in mind that if you’re a decent sleeper and have energy throughout your day, no need to panic if your device says otherwise. And technology grows more sophisticated over time. As long as our collective appetite for tracking doesn’t go anywhere, we can expect sleep trackers to get better.

find your sleep sweet-spot

Not all trackers simply tell you how much time you spent in bed. Some technology takes the 'simple' sleep tracker and tacks on additional functionality. For instance, in addition to your sleep time, Sense and Withings Aura also measure bedroom temperature, brightness and loudness. These metrics can help users learn the bedroom environment that works best for them. (The Aura, with its tracker pad that goes under your mattress, is also a lamp that can shine certain colors of light to promote either sleep or wakefulness.) Both Sense and Aura have smart alarm capabilities, which wake you up within a window of time at the lightest part of your sleep cycle. Whether these are a game-changer vary from person-to-person, but at the very least they're a conversation-starter.

a subliminal sleep-aid

One thing sleep trackers do best is cueing you to pay more attention to sleep. In science, it’s called the Hawthorne effect: The mere act of observing (or, in this case, tracking) a certain behavior changes it, Martin explains. Just having a Sense on your nightstand is encouragement enough to put down the smartphone and go to sleep. Martin also recommends that people use trackers to review sleep patterns over time. For instance, you may think you skimp on sleep one or two nights a week when in reality it’s more. And if you learn that all of the devices are the things that are giving you agita and disrupting your sleep, remove all tech from your bedroom and buy yourself an alarm clock.