New Study Finds Cognitive Impairment In Older Adults Linked To Inconsistent Sleep

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A recent study suggests that individuals with fluctuating sleep patterns over the years may face an increased risk of cognitive impairment as they age.

The research, which analyzed data from 614 adults over two decades, found that those who reported the most variation in their sleep duration were more than three times more likely to experience cognitive impairment by the end of the study. The findings, published in JAMA Network Open, underscore the potential link between sleep variability and cognitive health in aging individuals.

Researchers collected data from participants who provided information on their sleep habits every three to five years during the study period. Additionally, cognitive testing was conducted for all participants. By the study’s conclusion, 7.2 percent of individuals, totaling 44 people, displayed evidence of cognitive impairment.

An associate professor of neurology and director of the Aging and Neurodegeneration Research Program at Monash University in Australia, Matthew Pase, PhD, says, “We know that sleep regularity — the consistency of sleep and wake times — is important for overall health.”

Having an Irregular Sleep Schedule Can Impact Brain Health

Dr. Pase, who wasn’t involved in the study, says “Variability in sleep may reflect irregular sleep schedules, which could increase the risk of dementia risk factors, it’s also possible that dementia risk factors could impact sleep regularity — someone with many health conditions may have irregular sleep due to medications, pain, and other comorbidities.”

The association between cognitive impairment and sleep variability may be influenced by the methodology used to gather data. Participants were required to recall and report their sleep duration, and individuals with dementia or cognitive issues might struggle to accurately remember or consistently provide this information over time, explains the study.

“High variability in reported sleep duration across time might be impacted by cognitive problems such as poor memory,” Dr. Pase says.

Marie-Pierre St-Onge, PhD, an associate professor and director of the Center of Excellence for Sleep and Circadian Research at Columbia University Irving Medical Center in New York City, suggests that beyond cognitive challenges, various reasons might lead individuals to report variations in sleep duration when queried only every three to five years.

Dr. St-Onge, who wasn’t involved in the new study, said, “There could be life events that influence sleep duration in one way or another — work versus retirement, loss of a spouse, illness. Because the study is observational, we can’t ascribe causality to these associations.”

What’s Considered Good Sleep Hygiene?

While the medical community lacks a consensus on the ideal amount of sleep for individuals aged 65 and older, St-Onge emphasizes the importance of good sleep hygiene. While most adults generally need at least seven hours of sleep a night, the specific sleep requirements for older adults may vary based on factors such as health status, sex, and life circumstances.

St-Onge recommends practicing good sleep hygiene, which involves cultivating habits that support healthy sleep, including maintain a consistent sleep duration and adhering to a regular sleep schedule.

Although the study highlights a potential connection between sleep variability and cognitive health in aging individuals, it’s crucial to interpret the findings cautiously. As researchers acknowledge, factors beyond cognitive challenges, such as recall accuracy and reporting frequency, may contribute to the observed link.

While more research is needed to explore the intricacies of this relationship, the study underscores the significance of prioritizing healthy sleep habits as individuals age.

According to Dr. Pase, when it comes to good sleep hygiene, this can also include sleeping in a dark, cool, and comfortable space, as well as avoiding bright lights after dark. This also includes avoiding stimulants close to bedtime, limiting alcohol, as well  and getting plenty of exercise, Dr. Pase says.

“It’s important for people to realize that sleep is important for health and to therefore make sleep a priority and schedule enough time for it, just like someone would schedule time to go to the gym,” Dr. Pase says.

And when it comes to promoting brain health over time, Dr. Pase adds that sleep is just one factor to consider.

Dr. Pase says, “Sleep is just one part of the bigger picture. Regular exercise, avoiding smoking, maintaining a healthy weight, having a healthy heart by avoiding or adequately treating high blood pressure and diabetes, being socially engaged, and looking after your mental health are all important.”