New research emphasizes the critical role of sleep in determining life expectancy. A December 2025 study from Oregon Health & Science University (OHSU), published in SLEEP Advances, identifies insufficient sleep as the second strongest behavioral predictor of shorter life expectancy in the U.S., following smoking. This finding surpasses other factors such as diet, exercise, and loneliness.

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Additionally, a study published in Nature in May 2026, which analyzed biological clock data from over 500,000 individuals, found that both inadequate and excessive sleep can accelerate aging in various organ systems, including the brain, heart, and immune system.

The OHSU study compared data from the Centers for Disease Control and Prevention (CDC) Behavioral Risk Factor Surveillance System between 2019 and 2025, revealing a consistent negative correlation between insufficient sleep and life expectancy across numerous states. Dr. Andrew McHill, the study's senior author, noted that while people often underestimate the importance of sleep, adequate rest is vital for both well-being and longevity.

The Nature study led by Dr. Junhao Wen at Columbia University added complexity to the relationship between sleep and aging. Researchers developed machine learning-powered aging clocks and discovered a U-shaped correlation where optimal biological aging was found in individuals getting between 6.4 and 7.8 hours of sleep per night. Both insufficient and excessive sleep were linked to accelerated aging.

A notable finding is that sleep consistency may more significantly affect mortality risk than duration. A UK Biobank study revealed that regular sleep-wake patterns predicted all-cause mortality more strongly than meeting specific hour targets. Another May 2026 study in JAMA Network Open supported this, indicating that individuals with consistent daily rhythms experienced slower epigenetic aging.

The American Heart Association's statement on circadian health emphasized that the body's internal clock regulates crucial functions, and disruptions in sleep timing can have detrimental effects, regardless of total sleep duration.

The biological importance of sleep is underscored by the fact that during deep sleep, the brain's glymphatic system removes waste, including proteins associated with Alzheimer's disease. Chronic sleep deprivation is linked to significant health risks, including high blood pressure, obesity, type 2 diabetes, cardiovascular disease, and depression—each of which independently contributes to reduced longevity.

The American Academy of Sleep Medicine recommends at least seven hours of sleep per night, defining insufficient sleep as regularly getting fewer than that. The OHSU study highlights a target range of 7 to 9 hours, while the Nature study warns that consistently sleeping more than 10 hours may also increase mortality risk.

To improve sleep hygiene, experts suggest several practical strategies: treat 7 to 9 hours of sleep as essential, prioritize consistent wake times, keep the bedroom cool and dark, avoid alcohol before bed, and limit caffeine in the afternoon. With the ability to significantly influence health, sleep is increasingly recognized as a vital component of longevity.