Sleeping Less Than 7 Hours Daily Linked to Shorter Life Expectancy, Study Warns

A new study has found that habitually getting insufficient sleep may go beyond causing simple fatigue—it could actually shorten life expectancy. The research suggests sleep duration has a stronger connection to lifespan than diet or lack of exercise.

According to ScienceDaily on January 4, researchers at Oregon Health & Science University (OHSU) published findings in the journal SLEEP Advances showing that regions where average daily sleep falls below seven hours tend to have shorter life expectancies.

The research team analyzed county-level life expectancy data from 2019 to 2025 in the United States, combined with large-scale survey data from the Centers for Disease Control and Prevention (CDC).

The results showed that sleep deprivation had a stronger correlation with life expectancy than diet, physical activity, or social isolation. Only smoking showed a greater impact than sleep. The researchers defined "sufficient sleep" as seven or more hours per day based on CDC guidelines. They noted that the association between sleep duration and life expectancy was consistently observed across nearly all states and analysis years.

"We knew sleep was important, but we didn't expect it to be this strongly connected to life expectancy," said Andrew McHill, a professor at OHSU's School of Nursing who led the study. "Getting seven to nine hours of sleep per day, when possible, could help with long-term health."

The researchers noted they did not identify the specific biological mechanisms by which sleep deprivation shortens lifespan in this analysis. However, they explained that given sleep's critical role in cardiovascular and immune function as well as brain health maintenance, sleep duration may serve as an indicator of overall health status.

Recent research from the University of Rochester's Neuroscience Center supports similar findings. According to that study, the brain's waste-clearing glymphatic system, which activates during sleep, did not function adequately in people sleeping less than six hours daily. This group showed accumulation rates of toxic proteins, including Alzheimer's-related amyloid beta, more than twice as fast as those sleeping seven to eight hours. The researchers explained that impaired brain cleansing function could increase systemic inflammation and raise the risk of premature death from cardiovascular disease by more than 25 percent.

Ultimately, cutting back on sleep appears to be a warning sign that literally erodes lifespan. South Korea is no exception. According to a 2024 report from the Korean Society of Sleep Research, the average sleep duration for Koreans is 6 hours and 58 minutes—18 percent below the OECD average, making it a nation of "chronic sleep poverty."