Sleep Trackers: How Accurate Are They?

A Pittsburgh neuroscientist weighs in on the accuracy of sleep trackers, citing recent studies that show wearables can estimate total sleep time fairly accurately but struggle with sleep-stage tracking. The devices often mistake quiet wakefulness for sleep, leading to overestimation of sleep duration. While trackers can identify significant changes in sleep architecture, their accuracy is limited, and users should not rely solely on their readings. A 2023 study found that students who slept six or fewer hours a night had a lower end-of-term grade-point average, highlighting the importance of using sleep trackers as a guide for improving sleep habits rather than solely relying on their accuracy. The devices can also affect users' subjective feelings of sleep quality, with a 2026 trial showing that participants who received regular reports and guidance on sleep habits reported improved sleep quality, even if their measured sleep time remained unchanged.