Actigraphic estimates of sleep duration in those reporting sleeping less than 7 h.

objectivesSleep duration < 7 h increases risk for chronic disease, which makes identifying short sleep duration critical to public health. The goal of this study is to evaluate objective short sleep duration among individuals who self-report insufficient sleep to test and evaluate predictors of the subjective-objective sleep duration difference.

methodsThis study presents baseline data from a sleep extension study involving adults aged 18-65, fluency in English, and self-reported sleep duration ≤ 7 h and elevated blood pressure. Objective sleep duration was measured with actigraphy, and subjective-objective sleep difference was calculated as the difference between self-reported habitual sleep duration and actigraphically measured sleep duration. Data were analyzed using regression models, Bland-Altman plots and exploratory spline-based logistic regression models.

resultsAmong 195 adults (age m = 42 ± 11 years), 54% had objective sleep duration < 7 h, and on average participants underestimated their sleep by 29 m. Under-reporting of self-reported sleep compared to actigraphy was associated with poorer objective sleep, including longer sleep onset latency (p < .001) and higher wake after sleep onset (p < .001), but also higher sleep efficiency (p < .001). In addition, perceived stress (p < .01) and self-reported sleep disturbance (p < .01) were associated with underestimation. A Bland-Altman analysis showed larger negative differences at longer objective sleep durations, consistent with both sleep perception patterns and statistical regression effects. Exploratory spline-based logistic modeling indicated a U-shaped relation with the lowest predicted probability of a large subjective-objective difference occurring at approximately 6.3 h of objective sleep duration.

conclusionThese findings highlight the importance of objective assessments to determine short sleep duration. Poorer subjective and objective sleep and higher stress may intensify perceptions of inadequate sleep, contributing to under-reporting. Sleep duration < 7 h increases risk for chronic disease, which makes identifying short sleep duration critical to public health. The goal of this study is to evaluate objective short sleep duration among individuals who self-report insufficient sleep and test and evaluate predictors of the subjective-objective sleep duration difference. Results demonstrate that half of individuals with self-reported sleep duration < 7 h did not have objective short sleep duration; most participants tended to underestimate their sleep duration, in particular those with poorer objective sleep, sleep disturbance, and higher stress. This difference between self-reported and objective sleep highlights the complexity of identifying individuals and populations with objectively short sleep duration for research and public health interventions.