How Effective Are Sleep Trackers and Are They Accurate?

September 29, 2015 2 min read

The average adult needs at least seven hours of sleep each night, though unfortunately many get a lot less. Approximately 70 million Americans have a sleep disorder, which may be why there's tremendous interest in popular fitness trackers that allow you to quantify and evaluate the quality of your sleep -- without the expense of a sleep specialist.

Personal sleep trackers seem like a great investment for anyone suffering from insomnia or sleep deprivation. But are they accurate?

Fitness trackers with sleep tracking capabilities, such as Fitbit, work by keeping track of how much you toss and turn in your bed to provide data on your sleep quality. This is done with accelerometers.

They are measuring an indirect approximation of sleep through movement . In order to make these estimations of deep or light sleep they are probably using an algorithm that takes into account the relative amount of movement that a person is having in the course of a night.  On the other hand, sleep specialists base their treatments and diagnoses on polysomnography, a special multifaceted test that typically involves sleeping in a controlled environment -- a sleep lab -- hooked up to plenty of wires. This gold-standard for sleep specialists measures everything from your brain activity, heart rate and breathing to your eye and muscle movements. Polysomnography generates far more information than currently any personal sleep tracker can, and is used to diagnose problems such as sleep apnea, circadian rhythm disorders, nighttime movement disorders and other health issues.

But some experts argue that sleeping in a controlled setting, such as a sleep lab, messes up the evaluation before it even has the chance to begin, since the person won't sleep the same as in their own bed. In general, a personal sleep tracker could be a good starting point for a better night of sleep, but these devices may not be enough to diagnose and solve your shuteye challenges.

If you're desperately tired but still skeptical, a sleep app for a smartphone may be a good place to start, since it will only set you back a few dollars compared with a hundred or more for a tracker device. Sleep Cycle, Sleep as Android and Sleepbot operate on the accelerometers built into a phone.