A recent study, published in the online edition of Neurology, the medical journal of the American Academy of Neurology, suggests that individuals who experience frequent sleep interruptions in their 30s and 40s may face an increased likelihood of developing memory and cognitive issues a decade later.
The research focused on analyzing the duration and quality of participants’ sleep. To calculate sleep averages, individuals wore a wrist activity monitor for three consecutive days on two separate occasions, roughly a year apart. The participants, with an average age of 40, slept for an average of six hours.
Yue Leng, PhD, of the University of California, San Francisco, the study’s author, emphasized the importance of understanding the relationship between sleep and cognition earlier in life due to the gradual accumulation of Alzheimer’s disease indicators in the brain before symptoms manifest. Leng stated, “Our findings indicate that the quality rather than the quantity of sleep matters most for cognitive health in middle age.”
The study involved 526 participants who were tracked over an 11-year period. Researchers assessed sleep duration and quality using wrist activity monitors, sleep diaries reporting bedtimes and wake times, and a sleep quality survey. Poor sleep quality was reported by 46 percent of participants, with a score greater than five on the survey.
Participants underwent memory and thinking tests, and researchers examined sleep fragmentation, measuring brief interruptions during sleep. The average sleep fragmentation was 19 percent, with participants divided into three groups based on their scores. Those with the most disrupted sleep had more than twice the odds of poor cognitive performance a decade later compared to those with the least disrupted sleep, even after adjusting for various factors.
Yue Leng emphasized the need for further research to explore the connection between sleep disturbances and cognition at different life stages and to identify critical periods when sleep may be more strongly associated with cognitive function.