Your Sleep Tracker May Not Tell the Whole Story

Wake-Up Call: Sleep trackers are nearly as common as pajamas when it comes to bedtime attire. Nearly half of American adults have used one, according to the American Academy of Sleep Medicine. While wearables claim to offer insights into how well and how long we sleep, new research indicates they aren’t sharing the complete picture of what’s actually happening when we hit the hay. 

The Study: Researchers monitored 107 study participants in a sleep clinic for eight nights. Each wore a research-grade actigraphy device on their wrist while also undergoing polysomnography. While actigraphy tracks movement, polysomnography (considered the “gold standard” of sleep tests) measures brain waves, breathing, and eye movement to determine when people are awake or asleep. 

The Takeaway: There were some discrepancies between the results of actigraphy and the results of polysomnography, suggesting wearable sleep trackers aren’t completely accurate. The wearable overestimated total sleep time and sleep efficiency (how long people are actually sleeping while in bed), but underestimated how much time they stayed awake by about 15 minutes. 

Keep in Mind: Wearable sleep trackers may do a better job of detecting sleep patterns over time, but they’re less accurate when it comes to more complex metrics.