• A new study reports that people in their 40s who have difficulty sleeping have a brain age 1.6 to 2.6 years older by the time they’re in their 50s compared to people who consistently get quality sleep.
• Experts say quality sleep can improve brain health and lower dementia risk and also decrease inflammation in the body and boost the immune system.
• You can promote a good night’s sleep by exercising during the day, putting away electronic devices before bedtime, going to sleep around the same time every night, and sleeping in a cool, darkened room.

Poor sleep quality in your 40s can affect your brain health later in life.

That’s the conclusion of a study published on October 23 in Neurology, the journal of the American Academy of Neurology.

In their findings, researchers from the University of California San Francisco (UCSF) and other institutions reported that people who have poor sleep quality around the age of 40 can have a brain age from 1.6 years to 2.6 years older than people who regularly get quality sleep.

“Our findings highlight the importance of addressing sleep problems earlier in life to preserve brain health, including maintaining a consistent sleep schedule, exercising, avoiding caffeine and alcohol before going to bed and using relaxation techniques,” Kristine Yaffe, MD, a study author and professor of psychiatry at UCSF as well as a member of the American Academy of Neurology, said in a news release.

“Future research should focus on finding new ways to improve sleep quality and investigating the long-term impact of sleep on brain health in younger people,” Yaffe continued.

Examining the link between sleep and brain health

In their study, researchers looked at 589 people with a mean age of 40. About 53% of participants were female and 39% were Black.

At the start of the research, participants were asked to fill out a survey with questions such as:

• Do you usually have trouble falling asleep?
• Do you usually wake up several times at night?
• Do you usually wake up far too early?

The researchers recorded the number of six poor sleep characteristics reported by each individual. The sleep habits included:

• short sleep duration
• bad sleep quality
• difficulty falling asleep
• difficulty staying asleep
• early morning awakening
• daytime sleepiness

Based on the responses, the researchers assigned participants into three groups:

• 0-1 poor sleep characteristics
• 2-3 poor sleep characteristics
• More than 3 poor sleep characteristics

At this initial phase, 70% of participants had no more than one poor sleep habit. Another 22% had 2 to 3 characteristics while 8% had more than 3 characteristics.

The researchers then sent the same survey to participants 5 years later. After another 10 years, they used MRI scans and machine learning tests to estimate the participants’ brain age.

The researchers reported that people with more than 3 poor sleep characteristics had an average brain age of 2.6 years older than people in the group with 1 or less characteristic. People with 2 to 3 characteristics had an average brain age of 1.6 years older than people in the lowest group.

“This study is impactful, since it demonstrates the relationship between poor sleep and accelerated brain aging in middle-aged adults, and offers promise that early treatment to manage sleep problems could prevent neurocognitive dysfunction in the future,” Clete Kushida, MD, a neurologist and a professor of psychiatry and behavioral sciences at Stanford University in California, told Healthline. Kushida wasn’t involved in the study.

Scott Kaiser, MD, a geriatrician and the director of Geriatric Cognitive Health for the Pacific Neuroscience Institute at Providence Saint John’s Health Center in California, not involved in the study, agreed.

“This is a highly compelling study — finding clear associations between poor sleep quality in midlife and accelerated brain aging — that contributes important insights into a critical body of research investigating connections between sleep and brain health.” Kaiser told Healthline.

Quality sleep is crucial for brain health

The researchers acknowledged a limitation of their study was the self-reporting by participants of their sleep habits. They also said the study was observational so it only produced an association between poor sleep and brain aging instead of a causation.

Nonetheless, the researchers said their findings emphasize the importance of quality sleep. Experts agreed.

“Sleep is without question important to brain health,” Kushida told Healthline. “We know that some sleep disorders, such as obstructive sleep apnea, can have effects on neurocognitive function and risk of cerebrovascular disease. Additionally, the relationship of poor sleep with brain aging is an important one as shown in the study.”

“There is an increasingly robust body of research demonstrating the critical importance of a good night’s sleep for brain health,” Kaiser said.

“Whether through the clearing of debris, ‘resetting’ of neural networks, or providing down-time to various systems, the quantity and quality of sleep [although in this particular study the accelerated brain aging findings were limited to those with poor sleep quality] have profound physiologic impacts that impact our day to day thinking, memory, and mood as well as our long-term risk of cognitive decline and dementia,” Kaiser noted.

Quality sleep essential for overall health

Sleep is now listed among the top lifestyle factors for maintaining good health.

Researchers have reported that quality sleep can:

• maintain critical body functions
• restore energy
• repair muscle tissue
• allow the brain to process new information

Past research has indicated that consistent quality sleep can lower a person’s risk of dementia.

Other research has concluded that quality sleep can also help a person lose or maintain weight, strengthen the heart, lower type 2 diabetes risk, boost the immune system, and decrease inflammation in the body.

Experts say it’s important to have good sleep hygiene at any age.

“Sleep is important in all ages,” Kushida said. “We know that in children and adolescents, sleep problems can lead to delayed growth and behavioral issues. Middle age is when many sleep disorders and medical disorders that impact sleep become more prevalent and increase further with age, and as demonstrated in this study, poor sleep in this age group is associated with advanced brain age,” he added.

How to get quality sleep

The Centers for Disease Control and Prevention (CDC) recommends differentl daily amounts of sleep at certain ages:

• Infants 4 to 12 months old: 12-16 hours (including naps)
• Toddlers 1-2 years old: 11-14 hours (including naps)
• Preschoolers 3-5 years old: 10-13 hours (including naps)
• School-age children 6-12 years old: 9-12 hours
• Teenagers 13 to 18 years old: 8-10 hours
• Adults: 7 hours or more

Getting a consistent amount of sleep isn’t always easy. The CDC offers tips to achieve quality sleep:

• spend time in bright light during the daytime
• exercise regularly, aiming for 30 minutes per day five days a week
• eat meals at consistent times
• avoid heavy meals, nicotine, caffeine, and alcohol before bedtime
• use a consistent routine to wind down at night
• put away electronic devices an hour before bedtime and sleep in a quiet, cool, and dark environment

Kushida added a few more items to this list.

• Go to sleep and wake up at approximately the same time every day.
• Avoid irregular long daytime naps.
• Avoid staying in bed longer than 20 minutes if you can’t go to sleep or can’t fall back asleep after awaking in the middle of the night.

Kaiser urged anyone with sleep difficulties to seek professional guidance.

“There are healthcare professionals with expertise in this domain who can further evaluate your issues and may offer effective solutions to improve sleep quality, including addressing the specific poor sleep characteristics —difficulty initiating or maintaining sleep, early morning awakening, and daytime sleepiness — assessed in this study and associated with accelerated brain aging,” Kaiser said.

Takeaway

Poor sleeping habits during your 40s may affect brain health in later years.

In a new study, researchers reported that a group of people with a mean age of 40 who experienced poor sleep hygiene showed brain ages 1.6 years to 2.6 years older than people the same age who practiced healthy sleep patterns.

Experts say quality sleep provides a number of health benefits from repairing muscle tissue to allowing the brain to process new information to lowering the risk of inflammation, and boosting the immune system.

They say you can improve your chances of getting a good night’s sleep by going to bed approximately the same time every night, putting away electronic devices an hour before retiring, and sleeping in a cool and darkened room.