A Good Night's Rest: The Best Sleep Apps
Credit: Andrey_Popov/Shutterstock.com

Sleep is crucial to brain functioning, memory formation and to life itself (look up fatal familial insomnia). But all too often, sleep is elusive. The Centers for Disease Control and Prevention (CDC) found in a 2009 survey of nearly 75,000 adults in 14 states that 35 percent reported sleeping fewer than 7 hours a night.

The amount of time an adult needs to sleep each night varies from person to person, and probably has to do with genetics. But the National Institutes of Health suggests that adults get between 7 and 8 hours of Zzzs each night. To keep you from falling short, a number of smartphone apps on the market claim to track your sleep. The apps aim to not only provide solid numbers on how many winks you're getting, but also to help you understand what might lead to a bad night's rest, so these triggers can be avoided.

Before we get to our reviews of these apps, a warning: Sleep experts are highly skeptical that any consumer gadgets can accurately measure how well a person sleeps. Generally, there are two types of sleep gadgets on the market. The first are the fitness trackers that have sleep-tracking capabilities. Most of these gadgets involve a wearable wristband or sensor that tracks your body movements as you sleep. The second category is smartphone apps, which use the accelerometer that is built into your phone to capture your movements. In this review, we focus on the smartphone apps, which don't involve wearing another device.

Even the gadgets that have wearable sensors, however, are unlikely to accurately measure how long people spend in the various stages of sleep, experts told Live Science in January 2014. Your body movement does not necessarily correspond to sleep stage, said West Virginia State University sleep scientist Hawley Montgomery-Downs. As you might imagine, a smartphone set next to you on the mattress introduces even more room for error, as its measurement of your movements will vary depending on factors like mattress firmness and whether you sleep with a partner.

Sadly, our Live Science office is not equipped with a research-quality sleep lab — like the ones where scientists use electroencephalography to measure brain waves, electrooculography to measure eye movements, and other tests — so we can't vouch for the accuracy of any of the smartphone apps we reviewed. Indeed, when we ran the apps concurrently, they often returned different results, and we can't always tell which is correct.

The home screen of the Sleepbot app
The home screen of the Sleepbot app
Credit: Stephanie Pappas for Live Science

However, most of these sleep-tracking apps have additional features such as "smart" alarms and white noise that may make them worth your while anyway. If you don't mind taking the data you get from these apps with a large grain of salt, our favorite is Sleepbot (iOS, Android). Happily, this app is free.

The graphs within the Sleepbot app show your body movements and sounds over the course of the night.
The graphs within the Sleepbot app show your body movements and sounds over the course of the night.
Credit: Stephanie Pappas for Live Science

Sleepbot has three major features: a motion-tracker, a sound-recorder and a smart alarm. You can choose to activate one, all or any combination of these features simply by tapping a checkmark next to each — making this app one of the easiest to navigate of all the apps we reviewed. To track your nighttime motion, plug in the phone (all of these sleep apps are battery hogs), start the app and place the phone face-down on your bed near your body. The sound-recording feature will automatically detect sleep-talking, snoring and bumps in the night and record clips so you can get a better idea of nighttime disturbances in the morning.

Sleepbot has a soothing blue-light display, but what sets it apart are the easy-to-read interactive graphs. These purport to show you whether you were awake, in light sleep or in deep sleep at each point during the night. The accuracy of these measurements is anyone's guess, but unlike several other apps tested, Sleepbot's motion sensor actually did capture the times a user knew she was awake, like middle-of-the-night bathroom trips. The sound sensor detected such midnight ramblings, too.

For data geeks, Sleepbot provides trend graphs going back 6 months that include your sleep times, wake times, sleep length and sleep patterns. There is an option to log in to a website to back up this data. Finally, Sleepbot offers a "smart" alarm that aims to detect when you're in light sleep to wake you at the best possible time within a 30-minute window before a time of your choosing. One downside to Sleepbot is that it doesn't let you customize this time frame (for example, choosing a 10-minute window), though you can set multiple alarms with a variety of pleasant ringtones. You can also pick a song from your own music library to wake you.

Runner-up

The home screen of the MotionX 24/7 app.
The home screen of the MotionX 24/7 app.
Credit: Stephanie Pappas for Live Science

Another good option that tracks sleep is MotionX 24/7 ($0.99 iOS). The advantage of MotionX 24/7 is that it's not just a sleep tracker — the app also includes a pedometer and a heart-rate monitor. There is a "timed activity" log for recording workouts and one for tracking body weight, as well as an option to set goals for the number of steps you want to take each day and the number of hours to sleep nightly. MotionX 24/7 also integrates with Apple's Health app.

The sleep-tracking portion of the app includes a movement monitor and a noise-activated sound recorder. The sound clips are conveniently embedded in the graph of each night's sleep. This app also has a test mode, so you can be sure your tossing and turning gets picked up by the motion monitor. However, compared with other apps tested, the motion monitor seemed less sensitive. The sound recorder picked up late-night wakeups, but the app did not necessarily record these as "awake" times, so the graph is an estimate of sleep, at best. MotionX 24/7 keeps sleep records for the last 30 days, which can be exported as a .CSV file or shared on Facebook and Twitter.

Like other sleep trackers, MotionX 24/7 has a smart alarm that aims to wake you during a phase of light sleep. The wake-up window can be customized between 1 minute and 60 minutes, with a default of 30 minutes. A similar smart alarm can be set in "powernap" mode for short snoozes.

Although MotionX 24/7's sleep graphs aren't as detailed as those of some other apps, the multifunctionality of this app more than makes up for it.

Other good apps

The Sleep Cycle app offers a customizable alarm.
The Sleep Cycle app offers a customizable alarm.
Credit: Stephanie Pappas for Live Science

Easy to navigate and personalize, Sleep Cycle ($0.99 iOS, Android) has a smart alarm with a customizable window and a library of soothing wake-up music. You can also choose an alarm from your own music library. The alarm can be snoozed with a simple tap on the phone, and the length of a snooze can be set at predetermined intervals or, in "intelligent" mode, will adjust automatically to wake you by the end of your wake-up window. Conveniently, Sleep Cycle lets you set your weekends to automatically turn off the alarm on days when it's not needed.

Sleep Cycle doesn't record nighttime sounds, but uses the phone's accelerometer to detect motion. There is a test function to ensure the phone is positioned well on the mattress. The resulting sleep graph is a bit harder to read than the graphs of other apps. The app includes white noise and a heart rate monitor, and has sections to record notes on sleep quality and mood upon wake-up. There's even a weather feature that displays the forecast each morning.

Smart Alarm Clock ($1.99 iOS, Android) offers multiple modes for combinations of motion-tracking and noise-recording, and includes a smart alarm. There is also a powernap mode for naps under 45 minutes. Along with a library of wake-up music for alarms, Smart Alarm Clock has a series of "chill-out" tracks, mostly white noise, for those who need a little help falling asleep. These can be set to play for up to 90 minutes.

Smart Alarm Clock offers nightly and monthly sleep graphs, though we found that the motion tracker did not capture every middle-of-the-night wakeup. There is a test mode for optimal phone positioning in bed, and the smart alarm window is customizable. A clear, illustrated tutorial introduces you to the app and explains how to change the settings. 

Offering similar features, Sleep Time+ ($1.99 iOS; free Android) is another good option, though without the noise-recording option. The app includes white noise and nature sounds to help you fall asleep and a smart alarm for wake-ups. Unfortunately, the wake-up window is not customizable and there is no test mode to ensure that your phone is properly placed in bed. The color-coded daily, weekly and monthly graphs will appeal to data-lovers, and the percentage breakdowns of sleep and wake time are easy to read. The app includes a section where you can make your own notes on your sleep quality, plus there's a heart-rate monitor.

The Pillow app records both your motion and sound and has a smart alarm, that aims to wait you up when you are sleeping lightly.
The Pillow app records both your motion and sound and has a smart alarm, that aims to wait you up when you are sleeping lightly.
Credit: Stephanie Pappas for Live Science

Designed with a pretty purple color scheme, Pillow (Free iOS) is a simple no-cost option for iPhone users. The smart alarm setting is easy to use and the wake-up window is customizable. The alarm ringtone options are extensive and pleasant. Pillow records both your motion and sound. The free version offers daily graphs, but for long-term trends, you'll have to upgrade to premium for $4.99. The cost of the full app pushes it down our list, as most of its premium features are offered at lower cost in other apps.

Like Pillow, Sleep Better (Free iOS, Android) requires an upgrade to premium ($1.99) to unlock the full features. The basic app offers a smart alarm with a 30-minute wake-up window and a 10-minute snooze interval. There are five free alarm sound options and free daily sleep statistics. The colorful graphs are easy to interpret, and unlike other apps, Sleep Better offers a dream journal section. With the upgraded version, you get more alarm customization options, weekly, monthly and yearly statistics and even insights on how the phase of the moon might affect your sleep. A nice feature in the free version is the ability to record specific triggers that might affect sleep, such as alcohol consumption, daily exercise and stress.

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