Performance evaluation of consumer sleep-tracking wearables and nearables in healthy young and older adults

Changes in sleep with aging are associated with risk for Alzheimer's and other neurological diseases, risk of accidents, and can be a predictor of health decline. For this reason, continuous sleep monitoring is of great interest for researchers, clinicians, and family members. The objective of this study was to assess the validity of consumer sleep-tracking devices in older relative to young adults.

Analyses were based on one night of sleep assessed in young (19-24 years; n = 13) and older adults (56-80 years; n = 19). Participants wore sleep-tracking wearables (Fitbit Sense 2, Oura Ring) and nearables (Withings Sleep Mat, Sleep Score Max) were positioned nearby. Sleep measures were compared to polysomnography.

Results suggest that devices may be less accurate in older relative to young adults in commonly reported measures. In older adults, devices underestimated total sleep time (Fitbit bias = -74.5 minutes, p=.012; Oura bias = -75.5, p = <0.0001; Withings bias = -45.7, p=.083; Sleep Score Max bias = -56.5, p=.001) and wake after sleep onset (Fitbit bias = -44.1, p=.012; Oura bias = -19.8, p=.2823; Withings bias = -32.1, p=.129; Sleep Score Max bias = -71.6, p=.006) and overestimated deep sleep time (Fitbit bias = -29.3, p=.013; Oura bias = 71.5, p=.001; Withings bias = 97.4, p = <0.0001; Sleep Score Max bias = 88.8, p = <0.0001). Devices performed poorly in identifying individual sleep stages, particularly deep sleep. Limits of agreement were generally greater in older adults than younger adults across all measures, suggesting less precision in measuring older adults' sleep.

Older adults interested in tracking their sleep and clinicians and researchers using consumer devices as a replacement for polysomnography should use caution when interpreting results from these devices.This paper is part of the Consumer Sleep Technology Collection.