We’ve all heard the phrase “make sure to get eight hours of sleep” – but recent research shows that the optimal range of shut-eye could be lower than you might think.
People who got between 6.4-7.8 hours of sleep a night were found to have better functioning immune systems, brains and hearts, researchers at the Columbia University Irvin Medical Center said in a recent study.
The findings suggest that getting too little or too much sleep are hallmarks of poorer overall health.
“Previous studies have found that sleep is largely linked to aging and the pathological burden of the brain. Our study goes further and shows that too little and too much sleep are associated with faster aging in nearly every organ,” Junhao Wen, an assistant professor of radiology at the school’s Vagelos College of Physicians and Surgeons, explained in a release.
open image in galleryThat supports the idea that sleep is important in maintaining organ health, he noted.
Women included in the study appeared to need more sleep than men, too, Marie-Pierre St-Onge, a professor at Columbia University who was not involved in the study, told The Washington Post.
“Women seem to do better with a little longer,” she said. “About 15, 20 minutes — which is interesting because it matches what we see in the general population and self-reported sleep duration, that tends to be slightly longer in women than men.”
That builds on years of past research drawing similar conclusions, citing hormones and an increased risk of sleep disorders.
Ticking clocks
The study used machine learning to detect signs of aging organs in 500,000 participants of the decades-long U.K. biobank study.
“The hypothesis is that different organs, even within the same person, age at different rates,” Wen told The Washington Post.
Researchers developed what are known as “aging clocks,” which show if a person’s organ is aging older than their actual age. They created dozens of clocks for organ systems throughout the body to see if the aging was linked to sleep.
That’s when they noticed the pattern: too much or too little sleep was associated with accelerated aging. Too little was fewer than six hours a night and too much was greater than eight hours.
open image in galleryToo little sleep was associated with chronic disease, such as obesity, Type 2 diabetes, high blood pressure and heart disease.
Both short and long sleep were tied to asthma, digestive disorders, late-life depression and chronic obstructive pulmonary disease, an incurable lung disease, the research found.
That suggests patients and experts should potentially alter how they think about sleep health going forward, Wen said. Although he pointed out that the study’s results should not be prescriptive and every body is different.
“Our study suggests there may be different biological pathways between long and short sleepers that lead to the same outcome, late-life depression, and we shouldn’t treat them the same way,” he said.