A new study led by researchers from Albert Einstein College of Medicine and Penn State College of Health and Human Development suggests that for older adults, the quality of sleep has a greater impact on cognitive performance than the number of hours slept.
Published in Sleep Health, the research focused on how time spent awake during the night affects information processing speed in people over 70. Participants were drawn from the Einstein Aging Study, which tracks aging and cognitive health among community-dwelling seniors in Bronx County, New York.
For 16 days, 261 participants wore wrist devices to monitor their sleep patterns and completed brief cognitive tests on smartphones six times daily. These assessments measured visual working memory, visuospatial memory, and processing speed. In total, more than 20,000 cognitive assessments were collected.
The findings showed that when an individual was awake for 30 minutes longer than their usual amount during the night, their processing speed slowed down the next day. Other factors such as napping, bedtime, or total sleep duration did not show a significant effect on cognitive performance.
Orfeu Buxton, Ph.D., professor at Penn State and lead author of the study, said: “Anyone who has stayed up too late knows that sleep can affect your cognition the next day. In this study, we wanted to identify which aspects of sleep health impact daily cognitive functioning so that people know how to improve their sleep. When it comes to ‘getting a good night’s sleep,’ it would appear that quality matters in the short term for older adults.”
Carol Derby, Ph.D., professor at Einstein and senior author of the study, noted: “Understanding the nuances of how sleep impacts older adults’ cognition and their ability to perform daily activities may indicate which individuals are at risk for later cognitive impairment, such as Alzheimer’s disease.”
The researchers found that those who experienced more wakefulness after falling asleep performed worse not only in processing speed but also in two tests measuring visual working memory.
Dr. Buxton added: “Repeatedly waking after you’ve fallen asleep for the night diminishes the overall quality of your sleep. We examined multiple aspects of sleep, and quality is the only one that made a day-to-day difference in cognitive performance.”
Nearly half of older adults report some form of disrupted sleep. The research team emphasized healthy habits such as consistent bedtimes and restful environments to promote better sleep quality over time. Dr. Buxton stated: “When it comes to sleep, no single night matters, just like no single day is critical to your exercise or diet. What matters is good habits and establishing restful sleep over time.”
They recommend evaluating sleeping conditions—such as avoiding screens before bed—and consulting healthcare providers about cognitive behavioral therapy if problems persist rather than relying on medication due to increased fall risks associated with sedatives.
Looking ahead, Dr. Derby commented: “The work demonstrating the day-to-day impact of sleep quality on cognition among individuals who do not have dementia suggests that disrupted sleep may have an early impact on cognitive health as we age. This finding suggests that improving sleep quality may help delay later onset of dementia.”
Other contributors included researchers from Montana State University, Clemson University, Brigham and Women’s Hospital, and Harvard Medical School.
