Sleep disruptions in 30s and 40s linked to cognitive decline a decade later, study finds

A recent study indicates that individuals in their 30s and 40s with more disrupted sleep patterns have over double the chance of suffering from memory and cognitive issues a decade later. In the early 2000s, scientists monitored the sleep quality of numerous subjects with wrist activity monitors that recorded sleep duration and movement, providing insight into sleep fragmentation.

An average participant's age was about 40 during this stage of the research. Standardized assessments of cognitive abilities such as processing speed, executive function, memory, and fluency were carried out a decade later on 526 identical participants. The research discovered that participants usually slept around six hours a night, with approximately a fifth of their sleep time disrupted.

The research, published in the medical journal of the American Academy of Neurology, Neurology, found that people with greater sleep fragmentation tended to have poor cognitive scores on all tests over a decade later. From 175 subjects with the most disturbed sleep, 44 displayed poor cognitive performance ten years later, opposed to 10 out of 176 participants with the least disrupted sleep.

The study revealed that individuals who slept less or had higher sleep fragmentation were predominantly male, Black, had a higher BMI, and had a history of depression or hypertension. Taking into account health factors and other demographics, the people with the most interrupted sleep were more than twice as likely to perform worse than average on the cognitve tests.

The research's author, Dr. Yue Leng of the University of California, San Francisco, highlighted the significance of understanding the link between sleep and cognition due to the substantial role disrupted sleep plays in raising the risk factor for Alzheimer’s disease. Despite indicating the importance of sleep quality over quantity for cognitive health in middle age, the research acknowledged that 1 in 3 Americans don’t get sufficient sleep leading to a higher risk of conditions including diabetes, stroke, cardiovascular disease, and dementia.

Dr. Leng believes that further research into the connection between sleep disturbances and cognitive abilities throughout different life stages could pave the way for preventing Alzheimer’s disease later in life. Scientists used a wrist monitor to assess sleep fragmentation during the study and these devices are now more commonly used to monitor sleep trends. However, for those struggling with sleep disorders such as sleep apnea or restless leg syndrome, professional intervention is necessary.

Despite sleep hygiene recommendations such as regular daytime exercise, relaxing bedtime routines, reduced evening screen time, and avoidance of large meals, caffeine, nicotine and alcohol, these might not be enough to address underlying sleep disorders. Hence it would be beneficial to consult a doctor to understand the root of the issues.