The research team said the strength of the connection shocked even them, calling the findings "remarkable."
It’s a fact you’re probably already keenly aware of in your own life, but the National Sleep Foundation’s 2025 Sleep in America poll confirmed that 60% of American adults aren’t getting enough sleep—and three out of every four say that “good quality sleep has a positive impact on their flourishing.” Now there’s even more evidence to back up the importance of solid sleep habits.
A large county-by-county analysis published this December in the journal Sleep Advantages suggests that sleep isn’t just a wellness bonus—it’s one of the strongest predictors of how long people may live. The research was conducted by a group of graduate students in the Sleep, Chronobiology and Health Laboratory of the Oregon Health & Science University (OHSU) School of Nursing.
To understand how sleep impacts longevity, the researchers examined sleep duration and life expectancy data from more than 3,000 U.S. counties between 2019 and 2025, relying on responses to a simple U.S. Centers for Disease Control and Prevention (CDC) survey question: “On average, how many hours of sleep do you get in a 24-hour period?”
Across the board, U.S. counties where more residents reported sleeping fewer than seven hours per night had shorter life expectancies. The link held steady year after year, including during the COVID-19 pandemic, and appeared regardless of income level, healthcare access, or whether a county was urban or rural.
When the team compared sleep to other major health risks, the results were striking. Sleep insufficiency ranked as the second-strongest predictor of reduced life expectancy—smoking being the factor most predictive of mortality. Sleep insufficiency outperformed well-known risks like physical inactivity, diabetes, and obesity. Even after researchers adjusted for factors such as education, employment status, health insurance, food insecurity, smoking status, weight, and more, insufficient sleep remained a meaningful predictor of how long people live.
One of the most revealing findings emerged at the local level. Neighboring counties often showed large differences in the share of residents getting enough sleep—sometimes a gap of 15 percentage points or more. Those differences aligned with life expectancy gaps that spanned several years, highlighting sleep as a potential target for local public health action.
While scientists have long understood that sleep and longevity are linked, the authors were even surprised by the overall correlation: “It’s intuitive and makes a lot of sense, but it was still striking to see it materialize so strongly in all of these models,” said Andrew McHill, PhD, one of the study’s senior authors and an associate professor at OHSU, via statement. “I’m a sleep physiologist who understands the health benefits of sleep, but the strength of the association between sleep sufficiency and life expectancy was remarkable to me.”
At the community level, strategies such as adjusting school start times, improving shift-work policies, and expanding sleep education could have real public health benefits. But the message for individuals is just as clear: Consistently aiming for seven to nine hours of sleep isn’t just about feeling rested tomorrow—it may influence long-term health and longevity.
Said Dr. McHill: “We’ve always thought sleep is important, but this research really drives that point home: People really should strive to get seven to nine hours of sleep if at all possible.”
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