Accuracy concerns regarding wearable sleep trackers

Research published in the journal Sleep Medicine has raised concerns regarding the accuracy of popular wrist-worn sleep trackers, such as Fitbit and Apple Watch. Studies involving approximately 2,000 participants suggest these devices often fail to align with a user’s subjective sleep quality, explaining only 2.5 to 16.2 percent of the difference in how refreshed a person feels.

Further findings indicate that these wearables may be unreliable for diagnosing insomnia, showing accuracy in only 39 percent of cases. While trackers showed acceptable agreement with the gold-standard polysomnography (PSG) in 82.4% of healthy sleepers, accuracy dropped significantly among those with insomnia. The devices may overestimate sleep duration by up to thirty minutes and frequently overlook nighttime awakenings if the user remains relatively still. Experts note that technology struggles to account for mental or emotional states, such as depression, which impact perceived rest.

Experts warn that relying solely on these metrics may provide a false sense of security, potentially delaying medical diagnoses and treatment for sleep disorders. In response to these limitations, new technologies like the DUVA One system have been introduced, utilizing in-ear sensors and environmental monitoring to address sleep disruptions in real time. Meanwhile, medical professionals advise patients to prioritize personal well-being and physical sensations over digital statistics, distinguishing between sleepiness and fatigue rather than relying solely on device data.