Sleep Duration and Cognitive Decline
Understanding the association.
This study (PMID: 32955572) investigates the association between sleep duration and cognitive decline in older adults, exploring how both insufficient and excessive sleep may impact cognitive function over time.
By analysing data from large cohort studies, the research aims to elucidate the complex relationship between sleep patterns and cognitive performance, highlighting the importance of optimal sleep duration for maintaining cognitive health in ageing populations
Key Points
This pooled cohort study of 20,065 participants from the English Longitudinal Study of Ageing and China Health and Retirement Longitudinal Study found an inverted U-shaped association between sleep duration and cognitive decline.
After adjusting for covariates, individuals who slept 4 hours or less per night and those who slept 10 hours or more showed faster global cognitive decline compared to the reference group of 7 hours per night.
The study suggests that cognitive function should be monitored in individuals with insufficient (≤4 hours per night) or excessive (≥10 hours per night) sleep duration
Future studies must examine the mechanisms underlying the association between sleep duration and cognitive decline.
Potential Mechanisms
The mechanisms by which sleep affects cognition may involve neurodegenerative processes, inflammation, and changes in brain structure due to poor sleep quality. Sleep is essential for memory consolidation and brain health, and disturbances in sleep can hinder these processes.
Practical Application
Based on the findings of this study, individuals need to aim for an optimal sleep duration of around 7 hours per night to maintain cognitive function and minimise the risk of accelerated cognitive decline. Those with consistently short (≤4 hours) or long (≥10 hours) sleep durations need to be aware of the potential impact on their cognitive health and consider seeking medical advice or adjusting their sleep habits if necessary. Regular monitoring of cognitive function may also be beneficial for these individuals.
Reference
Ma Y, Liang L, Zheng F, Shi L, Zhong B, Xie W. Association Between Sleep Duration and Cognitive Decline. JAMA Netw Open. 2020 Sep 1;3(9):e2013573. doi: 10.1001/jamanetworkopen.2020.13573. PMID: 32955572; PMCID: PMC7506513.