Sleep-tracking apps attempt to create a pattern of your sleep/wake cycles, but the question is, do they work?

Phone apps record body movement to distinguish between REM (deep sleep) and non-REM (lighter) sleep. To use these apps, you simply run them and keep the phone on and plugged in so the app can register your movements while you sleep. That is, if you are comfortable with keeping a radiation-emitting device (your phone) close to your head all night, and you don’t knock it off the bed during sleep.

Unfortunately, monitoring movement only isn’t a fail-safe way to determine sleep stages. The most accurate way to determine sleep cycle uses electrophysiological measurements of brain activity, breathing and body movements, as experts do in a sleep lab. Without these precise measurements and the correct interpretation of them, an app is fundamentally flawed.

Don’t become fanatical about getting a “perfect” sleep. Sleep deprivation studies show sleep loss is compensatory: If you lose sleep one night, you’ll recover it the next night or the next. One or two nights of interrupted sleep really doesn’t have an impact on cognitive performance. You’ll only suffer after many consecutive nights of sleep loss. It’s more important to focus on keeping a regular schedule. Set a regular time to retire and to wake, even if you work the night shift.

Sleep apps are general self-help programs, not medical solutions. Everyone is different, and if sleep apps work well for one person, they may not for another. If you are having ongoing problems with sleep, consult a medical professional.