Brain News – New study found that older adults who sleep for a short or long time experience greater cognitive decline than those who sleep a moderate amount.
In a new study, researchers at the Washington University School of Medicine turned to volunteers who participated in Alzheimer’s studies and went through an annual clinical and cognitive assessment. The participants also provided their blood samples for the test of high-risk Alzheimer’s genetic variant APOE4.
The researchers collected samples of cerebrospinal fluid from the participants to calculate the levels of Alzheimer’s protein. Each of the participants was asked to sleep with a small electroencephalogram (EEG) for 4-6 nights to monitor their brain activity during sleep.
The researchers acquired sleep and Alzheimer’s data on 100 participants whose cognitive performance was monitored for four and a half years. 88 among them reported no cognitive impairments, 11 participants reported mild impairments, and only one developed mild cognitive impairment. The average age was 75 when the sleep study was conducted.
The study findings showed that both short and long sleepers developed cognitive decline symptoms more than those who got a moderate amount of sleep, even when the effects of early Alzheimer’s disease were taken into account.
“Our study suggests that there is a middle range, or ‘sweet spot,’ for total sleep time where cognitive performance was stable over time. Short and long sleep times were associated with worse cognitive performance, perhaps due to insufficient sleep or poor sleep quality.” said Brendan Lucey, first author of the study published in the journal Brain.
It reported that cognitive scores decreased for the groups who slept less than 4.5 hours or more than 6.5 hours per night. Meanwhile, the scores remained stable for those participants in the middle of the range. EEG tends to yield estimates of sleep time that are about an hour shorter than self-reported sleep time,The research results correspond to 5.5 to 7.5 hours of self-reported sleep
According to Lucey, the findings can help keep people’s mind’s sharp as they age. He suggested that people who wake up feeling rested on short or long sleep durations should not forcefully change their habits.
To Know More You May Refer To:
Lucey, B. P., Wisch, J., Boerwinkle, A. H., Landsness, E. C., Toedebusch, C. D., McLeland, J. S., Butt, O. H., Hassenstab, J., Morris, J. C., Ances, B. M., & Holtzman, D. M. (2021). Sleep and longitudinal cognitive performance in preclinical and early symptomatic Alzheimer’s disease. Brain, 144(9), 2852-2862. https://doi.org/10.1093/brain/awab272