Day-to-Day Sleep Variability May Be a Key Feature of Chronic Insomnia: Study
USA: A new study published in JMIR Formative Research reports that adults with chronic insomnia experience greater night-to-night fluctuations in sleep patterns, particularly in measures such as sleep latency, compared to individuals with healthy sleep. The research also demonstrates that a contactless sleep monitoring device can effectively capture these variations, indicating that inconsistent sleep metrics may be a defining feature of chronic insomnia.
The study, led by Devon A Hansen from the Sleep and Performance Research Center at Washington State University, aimed to address a key gap in insomnia research—the lack of long-term, objective sleep data collected in real-world settings. Chronic insomnia affects a substantial proportion of adults and is linked to a range of adverse mental and physical health outcomes. While variability in sleep has long been recognized as a characteristic of insomnia, most assessments rely on subjective reports, limiting accurate evaluation.
For this purpose, researchers conducted a prospective cohort study involving 112 participants, including 83 individuals diagnosed with chronic insomnia and 29 healthy controls. Participants underwent continuous sleep monitoring over an eight-week period in their home environments using a radio frequency–based, contactless device. This technology enabled objective tracking of multiple sleep parameters, including sleep efficiency, sleep latency, intermittent wakefulness, total sleep time, and time spent in bed.
The study revealed the following findings:
- Individuals with chronic insomnia showed lower sleep efficiency compared to good sleepers.
- They experienced longer sleep latency, indicating more time taken to fall asleep.
- Increased intermittent wakefulness was observed, reflecting more frequent nighttime awakenings.
- Insomnia patients exhibited significantly greater night-to-night variability in sleep patterns.
- Variability in sleep efficiency, sleep latency, and intermittent wakefulness was higher compared to controls.
- Night-to-night inconsistency in sleep measures appears to be a key characteristic of chronic insomnia.
- Fluctuating sleep patterns may better represent insomnia than single-night or short-term assessments.
- Contactless, radio frequency–based devices were effective in objectively monitoring sleep over extended periods.
- These devices enabled continuous sleep tracking in home environments without disrupting natural sleep conditions.
- The approach improves ecological validity compared to traditional laboratory-based sleep studies.
The authors highlight that such technologies could play a valuable role in both clinical practice and large-scale population studies by enabling better identification and monitoring of insomnia. Objective tracking of sleep variability may also help guide personalized treatment strategies and improve patient outcomes.
Overall, the study highlights that chronic insomnia is not only characterized by poor sleep quality but also by significant night-to-night inconsistency. These findings support the growing role of wearable and contactless technologies in advancing sleep research and management.
Reference:
Hansen D, Peterson M, Finlay M, Gottlieb E, Danoff-Burg S, Raymann R, Buchwald D, Watson N Assessing Night-to-Night Sleep Variability as a Hallmark of Chronic Insomnia Using Longitudinal, Contactless, Mobile Sleep Monitoring: Prospective Cohort Study JMIR Form Res 2026;10:e73969 URL: https://formative.jmir.org/2026/1/e73969 DOI: 10.2196/73969
Next Story