A research team at the University of California has uncovered a link between sleep quality in midlife and brain atrophy, a phenomenon often associated with dementia. They came to this conclusion after following 600 adults, with an average age of around 40, over several years.
The researchers questioned the participants about various aspects of their sleep, and also determined each person’s brain age by analysing their brain scans using machine learning algorithms.
The results showed that, even after taking into account factors such as age, lifestyle and general health, adults who had trouble sleeping showed accelerated brain ageing.
Individuals who complained of moderate difficulty sleeping had brains that were 1.6 years older than those reporting good sleep. This phenomenon was even more pronounced for adults with the most difficulty sleeping: in their case, the gap rose to 2.6 years.
The experts found that the acceleration of brain ageing was particularly linked to having difficulty falling asleep and waking up early, with the feeling of not having rested sufficiently.
Curiously, sleep duration did not seem to have a significant impact on this phenomenon, even though previous studies have claimed that shorter sleep leads to an increased risk of cognitive decline and dementia.
“While we can’t say that poor sleep causes dementia, earlier research has established an association. Even if the cause of dementia is unrelated to sleep, it’s possible that poor sleep may advance or exacerbate cognitive symptoms,” study first author Clémence Cavaillès outlined.
These findings show how important good sleep is for our health. “The study shows that poor sleep could be a target for early interventions to prevent possible cognitive decline,” study senior author Kristine Yaffe added.
And the stakes are high: the frequency of sleep problems has been rising steadily in recent decades. The almost constant presence of light, stress and sedentary lifestyles are among the main factors explaining the prevalence of poor sleep in modern society.