Sleep trackers struggle to accurately measure sleep quality, study finds

New research indicates that wearable sleep trackers often fail to accurately reflect how individuals actually feel about their rest. A study involving more than 2,000 people found that device measurements explained only 2.5% to 16% of the variation in how people rated their sleep quality, leaving up to 98% of the perceived experience unaccounted for by technology.

These devices struggle significantly with accuracy in specific populations. While trackers showed acceptable agreement with the gold-standard polysomnography (PSG) in 82.4% of healthy sleepers, accuracy dropped to just 39.4% among individuals with insomnia. The technology often fails to detect nocturnal awakenings if the user remains relatively still and cannot account for emotional or mental states that impact 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. Medical professionals advise that users should prioritize personal well-being and physical sensations over digital statistics.