If you want to age well, the amount of sleep you get matters. A new study suggests there’s a “Goldilocks” time frame you want to aim for ― and it’s slightly less than eight hours.
Analyzing biological clocks throughout the human body, researchers found that too few hours of sleep (anything less than six hours) may speed biological aging in the brain, lung, heart and immune system. But too much sleep (more than eight hours) also accelerates aging in nearly every organ in the body, according to study, published in the journal Nature last month.
If you’re looking to age minimally, the “sweet spot” is between 6.4 and 7.8 hours of sleep per day.
Getting either too much or too little sleep was also associated with a range of physical health conditions, including obesity, type 2 diabetes, hypertension, coronary artery disease and gastritis. Insufficient and excessive sleep durations were also significantly associated with depression and anxiety disorders.
The study supports “the idea that sleep is important in maintaining organ health within a coordinated brain-body network, including metabolic balance and a healthy immune system,” Junhao Wen, the lead researcher and an assistant professor of radiology at Columbia University Vagelos College of Physicians and Surgeons, said in a press release.
Wen and his colleagues used advanced statistical models called “aging clocks” to figure out the amount of sleep that’s associated with accelerated aging.
While most aging clocks estimate biological aging across the entire body, organs age at different rates. Wen and his team developed organ-specific aging clocks that may provide patients with more personalized and precise insights into their health.
“In the liver, for example, we have an aging clock built with protein data, an aging clock of metabolic data, and an aging clock of imaging data,” Wen said.
The hypothesis is that different organs, even within the same person, age at different rates, Wen told The Washington Post.
This doesn’t mean that sleep duration alone is aging our organs faster or slower, but too much or little sleep may be markers of poorer overall health in the body.
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Short and long sleep sessions were also significantly associated with depression and anxiety disorders.
One limitation for the study? Wen said more research is needed involving people of Asian and African descent, since the data for sleepers was taken from U.K. Biobank data, which is heavily weighted toward people of white European ancestry.
Why is too much sleep a bad thing?
Research has long confirmed that chronically under-sleeping can lead to a reduced lifespan and a range of health issues: hypertension, cardiovascular disease, stroke. But those who love to sleep may wonder: Why might too much sleep be a problem?
“Chronically long sleep time is associated with many health issues because oversleeping is often a byproduct of an underlying disease such as a sleep disorder like sleep apnea, inflammatory conditions, cancer, neurodegenerative disorder, and poor mental health,” said Dr. Chelsie Rohrscheib, a neuroscientist and researcher at Wesper, a company that designs at-home tools for diagnosing sleep disorders like sleep apnea.
Some studies have shown that long-sleepers have markers of inflammation, which is associated with diseases like cardiovascular disease and cancer, said Rohrscheib, who is not affiliated with this current study.
“The other answer is that long sleeping increases a sedentary lifestyle and reduces the total amount of physical activity achieved each day,” Rohrscheib told HuffPost.
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The study showed that women may need a little more sleep than men.
Women need a little more sleep.
The study also found that women may need a little more sleep than men. The difference is relatively small, though, said Rohrscheib: typically about 10 to 20 additional minutes per night.
The exact reasons for this remains unclear, but sleep researchers believe it may be related to hormonal differences and fluctuations throughout life, particularly during the luteal phase of the menstrual cycle, pregnancy and menopause.
“Others have proposed that women may experience greater emotional and cognitive demands, which could increase the need for sleep to support essential brain functions such as memory consolidation, emotional regulation, and overnight recovery,” she said.
The “sweet spot” is less than eight hours, what we traditionally associate with quality sleep.
Dr. Chris Winter, a a neurologist and host of the podcast “Sleep Unplugged,” said the study’s most interesting finding was its suggested optimal sleep range of 6.4 to 7.8 hours per night ― slightly below the eight hours many of us have been taught is the sleep “magic number.”
“The range is essentially an average of seven hours of sleep, not eight,” Winter, who was not affiliated with the study, told HuffPost. “I would love to dislodge from the public’s collective mentality about sleep that ‘eight hours’ of sleep is ideal for everyone, or even attainable for everyone. It’s not.”
Winter’s takeaway is that we should aim for a consistent seven hours or so on average, though if eight works for you, more power to you. A person’s need for sleep varies greatly based on age, lifestyle and genetics.
“If you struggle to get eight consistently, this is not something to overcome to optimize your health,” he said. “It may simply be that your body favors a number below what you are shooting for, yet still well within the range of optimized.”
