December 15, 2025, 6:04 pm | Read time: 5 minutes
Not just healthy eating or exercise: A new longevity study highlights the underestimated importance of sleep for a long life. FITBOOK author Friederike Ostermeyer explains the key findings of the U.S. study and why at least seven hours of restful sleep not only increases satisfaction but also life expectancy.
Almost every second German sleeps less than six hours a day. One in four suffers from severe sleep disorders.1 The phenomenon is similarly widespread in the U.S. The negative health impacts are well-documented in previous studies. Each poorly slept night increases the risk of diabetes, obesity, dementia, gastrointestinal issues, depression, and much more. But how does collective sleep deprivation affect entire regions? This previously unanswered question was the focus of longevity researchers at Oregon Health & Science University, aiming to better understand the impact of sleep on the overall life expectancy of the U.S. population. The results, published in the journal “Sleep Advances,”2 surprised even the scientists. They discovered only one other habit that shortens life even more.
Comprehensive Health Data from Over 3,000 U.S. Regions Analyzed
Sleep plays a crucial role in nearly all biological processes, including the immune system and brain function. Unfortunately, nighttime rest is often neglected, postponed to the weekend, or has already become a significant problem in daily life. Shift workers, in particular, struggle with the effects of irregular sleep. To better understand the importance of sleep for a long life, researchers analyzed comprehensive datasets from over 3,000 U.S. counties. These were collected between 2019 and 2025 through telephone surveys by the CDC and cover almost the entire U.S. In addition to sleep duration, participants also answered questions about diet, exercise, income, education, smoking, access to medical care, and more.
How the Researchers Conducted Their Analysis
In a multi-stage filtering process, they calculated the proportion of the population with chronic sleep deprivation (< 7 hours) per county and checked whether these regions were characterized by a generally shorter life expectancy. The scientists accounted for other risk factors as much as possible. As is known from longevity research, not only too little sleep but also an unhealthy diet, lack of exercise, or loneliness increase the risk of death.
Sleep as a Central Longevity Factor
A clear pattern emerged: Regions where a larger portion of the population regularly sleeps too little have, on average, a lower life expectancy. Sleep deprivation is thus one of the strongest factors for reduced life expectancy. “I did not expect the connection to be so strong,” says study leader Dr. Andrew McHill in a university statement.3 “We have always known that sleep is important, but this research really underscores it: One should aim for seven to nine hours of sleep whenever possible.” The impact of sleep deprivation was even more pronounced in the statistical models than that of diet and exercise. Interestingly, only smoking had a more negative effect as a behavioral factor.
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Study Leader: Without Sleep, Everything Is Nothing
Could sleep deprivation be the unhealthiest deficiency of all? For study leader McHill, there is a lot pointing to this, as he explains when asked by FITBOOK. “We know that rodents die after about 30 days without sleep. They are then no longer able to fight infections and regulate their body temperature.” In humans, it is known that too little sleep not only makes one sick but also slows down healing processes. Additionally, sleep deprivation tends to lead to unwise decisions that can sometimes have fatal consequences. “Sleep affects all biological processes and can therefore lead to a shorter life expectancy in various ways,” says McHill. Although research has not yet fully clarified why humans and animals need to sleep, its importance is evidently immense. “If sleep did not have an absolutely vital function, it would be the greatest mistake the evolutionary process ever made.” McHill’s advice is therefore: “Sleep should always be a top priority.”
Questions the Study Does Not Answer
The result is based on millions of surveys conducted over six years. Thus, the study shows a robust connection between sleep deprivation and reduced life expectancy. Unfortunately, it cannot provide insights into how exactly sleep deprivation reduces life expectancy and what role sleep quality plays. Sleeping in is also no guarantee for a long life. The results apply to regions, not individuals. Additionally, the findings are specific to the U.S., whose work culture, social systems, and health care differ significantly from those in Europe. Universally, the importance of sleep for longevity research might be summarized as follows: Those who spend their nights with at least seven restful hours of slumber do not sleep their life away but rather sleep their life longer. Exercise, social contacts, and a healthy diet are beneficial.