Among adults self-reporting sleep ≤7 h, only 54% had objectively measured short sleep duration (<7 h), with most participants underestimating their sleep by an average of 29 minutes, particularly those with poorer objective sleep, sleep disturbance, and higher stress.
Key Findings
Results
Only 54% of adults who self-reported sleeping ≤7 hours had objectively confirmed short sleep duration (<7 h) by actigraphy.
Sample consisted of 195 adults aged 18–65 (mean age 42 ± 11 years) with self-reported sleep duration ≤7 h and elevated blood pressure.
This is baseline data from a sleep extension study.
The remaining ~46% of self-reported short sleepers did not have objectively short sleep duration, indicating substantial misclassification.
Objective sleep duration was measured with actigraphy.
Results
On average, participants underestimated their sleep duration by 29 minutes compared to actigraphic measurements.
The subjective-objective sleep difference was calculated as the difference between self-reported habitual sleep duration and actigraphically measured sleep duration.
The direction of error was predominantly underestimation (participants believed they slept less than actigraphy indicated).
Bland-Altman analysis showed larger negative differences at longer objective sleep durations, consistent with both sleep perception patterns and statistical regression effects.
Results
Poorer objective sleep quality was associated with greater underreporting of sleep duration.
Longer sleep onset latency was associated with underreporting (p < .001).
Higher wake after sleep onset (WASO) was associated with underreporting (p < .001).
Higher sleep efficiency was also associated with underreporting (p < .001).
These associations were identified using regression models.
Results
Higher perceived stress and greater self-reported sleep disturbance were associated with underestimation of sleep duration.
Perceived stress was significantly associated with underestimation (p < .01).
Self-reported sleep disturbance was significantly associated with underestimation (p < .01).
The authors suggest that poorer subjective and objective sleep and higher stress may intensify perceptions of inadequate sleep, contributing to under-reporting.
Results
Exploratory spline-based logistic modeling revealed a U-shaped relationship between objective sleep duration and the probability of a large subjective-objective sleep difference.
The lowest predicted probability of a large subjective-objective difference occurred at approximately 6.3 hours of objective sleep duration.
This U-shaped relation suggests that both very short and longer objective sleepers are more likely to show large discrepancies between self-reported and measured sleep.
The analysis was described as exploratory.
Methods
The study enrolled adults with self-reported short sleep and elevated blood pressure as part of a sleep extension study.
Eligibility criteria included age 18–65, fluency in English, self-reported sleep duration ≤7 h, and elevated blood pressure.
The sample size was 195 adults.
Data analyzed represent baseline measurements prior to any sleep extension intervention.
Analytical methods included regression models, Bland-Altman plots, and exploratory spline-based logistic regression models.
What This Means
This research suggests that when people say they are not getting enough sleep, objective measurements often tell a different story. In a study of 195 adults who reported sleeping 7 hours or less per night (and who also had elevated blood pressure), researchers used wrist-worn activity monitors (actigraphy) to measure actual sleep duration. They found that nearly half of these self-reported short sleepers were actually getting at least 7 hours of sleep according to the device — meaning self-reports alone significantly overestimated how many people were truly sleep-deprived. On average, participants believed they were sleeping about 29 minutes less than the actigraph recorded.
The study also identified who was most likely to underestimate their sleep. People with worse sleep quality — such as taking longer to fall asleep, waking up more during the night, or reporting more sleep disturbances — tended to think they slept less than the monitor indicated. Higher levels of perceived stress also contributed to underestimating sleep. Interestingly, a statistical analysis suggested that the gap between perceived and measured sleep was smallest at around 6.3 hours of objective sleep, with larger gaps at both shorter and longer sleep durations.
This research suggests that relying solely on self-reported sleep duration to identify people at risk from insufficient sleep may be inaccurate, especially for public health efforts and research studies. People who feel stressed or experience poor sleep quality may be especially prone to thinking they sleep less than they actually do, complicating efforts to target interventions at those who truly need them. Objective tools like actigraphy may provide important additional information when identifying individuals with genuinely short sleep duration.
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Baron K, Landvatter J, Wilson A, Duffecy J, Bress A, Conroy M, et al.. (2026). Actigraphic estimates of sleep duration in those reporting sleeping less than 7 h.. Journal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine. https://doi.org/10.1007/s44470-026-00072-0