Study Suggests Sleep May Predict Lifespan Better Than Diet or Exercise

Sleep may be a stronger predictor of lifespan than diet or exercise, according to a new analysis by researchers in the United States. While healthy eating and regular physical activity remain essential for overall health, the study found that consistently sleeping fewer than seven hours per night was more strongly associated with shorter life expectancy.

Scientists at Oregon Health & Science University analyzed nationwide survey data collected between 2019 and 2025, examining self-reported sleep duration alongside mortality risk. They defined fewer than seven hours of nightly sleep as insufficient and compared its effects with other lifestyle and socioeconomic factors.

Even after accounting for physical inactivity, employment status, education level and other health-related behaviors, the connection between inadequate sleep and reduced life expectancy remained strong. Among all the factors examined, only smoking showed a stronger association with premature death.

Lead author Andrew McHill, a sleep physiologist at OHSU, said the researchers were surprised by how powerful the relationship appeared. He noted that although experts have emphasized the importance of sleep for years, the findings suggest that regularly getting seven to nine hours of sleep may be just as important as traditional advice about diet and exercise.

How sleep influences the body

The study was observational, meaning it cannot prove that short sleep directly causes earlier death. However, it adds to a growing body of evidence linking sleep quality and duration to long-term health outcomes.

Previous research has shown that even one night of severe sleep deprivation can disrupt brain function, impair attention and decision-making, and alter immune system activity. Over time, chronic sleep deficiency has been associated with obesity, type 2 diabetes, hypertension and cardiovascular disease — all conditions that can reduce lifespan.

Researchers also note that insufficient sleep can increase levels of inflammatory markers and stress hormones such as cortisol. Elevated cortisol and chronic inflammation may gradually damage blood vessels and strain the cardiovascular system, increasing the long-term risk of stroke, heart attack and other serious illnesses.

Poor sleep additionally affects hormones involved in appetite regulation and blood sugar control, potentially contributing to weight gain and metabolic dysfunction over time.

How much sleep do adults need?

Major professional organizations, including the American Academy of Sleep Medicine and the Sleep Research Society, recommend that most adults get at least seven hours of sleep per night. Some studies suggest that “catch-up sleep” on weekends may partially offset weekday sleep deprivation, but regular sleep restriction still appears harmful.

Experts emphasize that sleep quality matters alongside sleep duration. Conditions such as insomnia or sleep apnea can repeatedly interrupt sleep, leaving people fatigued even if they spend enough time in bed. Untreated sleep disorders can also raise the risk of cardiovascular and metabolic disease.

The researchers acknowledge that the OHSU analysis relied on self-reported sleep data, meaning some participants may not have accurately estimated their usual sleep duration. Still, the large national sample and the consistency of the findings across multiple statistical models strengthen confidence in the overall results.

What can help improve sleep?

Unlike certain risk factors for early death, such as genetics, sleep habits are at least partially modifiable. Sleep specialists recommend maintaining a consistent sleep schedule, limiting screen exposure late in the evening, and creating a dark, quiet and cool sleeping environment.

Relaxation practices such as yoga, tai chi and breathing exercises may help the body transition into sleep more easily, particularly for people who struggle to relax at night. Experts also recommend reducing caffeine intake late in the day and avoiding heavy evening meals that may interfere with sleep quality.

McHill and his colleagues argue that public health messaging should treat sleep as equally important as diet and exercise. They suggest that schools, workplaces and policymakers consider sleep more carefully when designing schedules and daily routines, given the growing evidence that chronic sleep deprivation carries serious long-term health consequences.

The findings, published in the journal Sleep Advances, add to a growing scientific consensus that prioritizing adequate sleep is not simply about improving daily energy and concentration. A full night of quality sleep may also play a major role in determining long-term health and lifespan.