Sleep researchers found an interesting link between sleep, memory, and old age. Accordingly, people who had quality sleeps during their younger and middle-aged years appear to have better mental functioning in old age than their sleep-deprived counterparts.
Researchers Michael K. Scullin, PhD. and Dr. Donald Bliwise, PhD. detailed the results of their extensive reviews of approximately 200 multidisciplinary studies about sleep, cognition, and aging that understood and explored sleep and mental functioning across young (aged 18 to 29), middle-aged (aged 30 to 60), and elderly participants (aged 60 and above). Some of these studies dated back to 1967.
The reviewed studies asked participants their typical sleeping patterns, including length of sleep, how long it takes for them to fall asleep, the frequency of mid-night wakefulness, and their experiences with daytime sleepiness.
To further build an extensive and integrated review, the researchers also correlated the study results from several brain-wave studies and experiments involving sleep deprivation, napping, and sleep intervention including the use of sleep medications.
Take note that sleep has always been linked to healthier mental functioning. For instance, Scullin and Bliwise mentioned that “deep sleep” or “slow-wave-sleep” helps in memory by piecing together experiences from the day, replaying them, and strengthening them for better recollection.
When people reached middle-aged, their daytime or afternoon naps increase and work together with quality nighttime sleep to better facilitate memory formation.
Old age however impairs mental functioning as it disrupts nighttime sleep and causes lesser deep sleep and dream sleep.
But the results of the extensive and integrated review were interesting. “We came across studies that showed that sleeping well in middle age predicted better mental functioning 28 years later,” said Scullin.
An improved mental functioning for people in old age who, moreover, had better sleeps when they were in their younger and middle-aged years further cements the importance of quality sleep and its relationship with mental health. In addition, the review results suggest that improving sleep early in life may help in delaying or even reversing age-related changes in mental functioning, specifically memory and thinking.
“It’s the difference between investing up front rather than trying to compensate later,” said Scullin. “People sometimes disparage sleep as ‘lost’ time, but even if the link between sleep and memory lessens with age, sleeping well still is linked to better mental health, improved cardiovascular health and fewer, less severe disorders and diseases of many kinds.”
Dr. Scullin is the director of Sleep Neuroscience and Cognition Laboratory at Baylor University while Dr. Bliwise is a professor of neurology at Emory University School of Medicine. Further details of the study are in the article Sleep, cognition, and normal aging: Integrating a half century of multidisciplinary research”published in 2015 in the journal Perspectives in Psychological Science.