Nature Aging Feng Jianfeng/Cheng Wei of Fudan University reveals that 7 hours of sleep every night is just right, too much or too little sleep can damage the brain and mental health

Sleep duration, mental illness, and dementia are closely related to iNature older adults
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However, the underlying genetic mechanisms and brain structural changes remain unclear
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On April 28, 2022, Feng Jianfeng and Cheng Wei of Fudan University jointly published a research paper entitled "The brain structure and genetic mechanisms underlying the nonlinear association between sleep duration, cognition and mental health" in Nature Aging.
Data from the UK Biobank (nearly 500,000 people, mostly participants aged 38-73 of European ancestry, including 94% white), identified a non-linear association between sleep, with approximately 7 hours being the optimal sleep time (sleep Too much or too little sleep is associated with poorer cognitive performance and mental health), while genetic and cognitive factors, brain structure and mental health are key indicators
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The brain regions most important for this interconnection include the anterior central cortex, lateral orbitofrontal cortex, and hippocampus
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Longitudinal analysis showed that insufficient and excessive sleep duration was significantly associated with cognitive decline in participants at follow-up
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In addition, structural equation modeling identified a unified model incorporating polygenic risk scores (PRS), sleep, brain structure, cognition, and mental health
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Taken together, this study suggests possible genetic mechanisms and changes in brain structure that may underlie the nonlinear relationship between sleep duration and cognitive and mental health
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Sleep plays an important role in cognitive processing and maintaining mental health, including consolidation of memory and emotional processing
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Sleep also provides important neuroprotective functions by removing waste
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Changes in sleep duration are an important sleep feature associated with a variety of diseases and psychiatric disorders, including cardiovascular and cerebrovascular diseases and dementia
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Sleeping less than 4-5 hours per night is associated with increased mortality
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Prolonged sleep duration has been identified as a potential marker of dementia
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Changes in sleep patterns, including difficulty falling and staying asleep, decreased sleep quantity and quality, and decreased sleep efficiency are important features of the aging process
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As a result, sleep disturbances are prevalent in the elderly population and may be accompanied by cognitive decline and declining health
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On a related note, a recent study demonstrated an inverted U-shaped association between sleep duration and overall cognitive decline, with sleep durations of less than 4 h or more than 10 h being detrimental
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Furthermore, a U-shaped association was observed between nighttime sleep duration and cerebrospinal fluid (CSF) amyloid deposition biomarkers in older adults, with an optimal sleep duration of approximately 6 h
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However, in a large cohort, the optimal level of sleep duration and its relationship to genetic and brain mechanisms, as well as cognitive and mental health, remains to be determined
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Sleep disturbances are associated with detrimental changes in brain structure in older adults
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Previous research has shown that in participants over the age of 55, ventricular volume increased by 0.
59% for every hour of sleep time reduction
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Shorter total sleep time in middle-aged and older adults is associated with impaired white matter microstructure
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Age-related shrinkage of a brain region involved in sleep regulation may contribute to sleep disturbances in the elderly population, a longitudinal study suggests
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Although previously discussed possible non-linear relationships between sleep and behavioral measures, previous reports considering sleep duration and brain structure have focused on linear relationships
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Research Guidelines (Image courtesy of Nature Aging) To address whether brain and genetic mechanisms underlie the nonlinear association between sleep duration, cognition and mental health, this study investigated middle-to-late adulthood using a large cohort from the UK Biobank.
sleep duration
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This large cohort allowed the researchers to pinpoint the interaction between age and sleep
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The UK Biobank is a large database containing cognitive assessments, the Mental Health Questionnaire (MHQ), brain imaging and in-depth genetic information from UK participants
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The study has four goals: first, to investigate whether there are non-linear associations between sleep duration and various mental health conditions and cognitive performance; second, to use neuroimaging data to study the relationship between sleep duration and brain structure; third Third, use structural equation modeling to explore the relationship between sleep, PRS, brain structure, mental health, and cognitive function; finally, longitudinal analysis is used to examine the directionality and direct correlation of sleep duration, cognition, and mental health
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The study hypothesized that there are non-linear associations between sleep duration and mental health, cognition and brain structure
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Suboptimal sleep duration was associated with subsequent poorer cognitive performance and mental health symptoms
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Furthermore, the study hypothesizes that this nonlinear association between sleep duration and behavioral measures may be supported by brain and genetic mechanisms
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Using data from the UK Biobank (nearly 500,000 people, mostly participants aged 38-73 of European ancestry, including 94% white), the study identified a non-linear association between sleep, with around 7 hours being optimal Sleep duration (both too much or too little sleep is associated with poorer cognitive performance and mental health), while genetic and cognitive factors, brain structure and mental health are key indicators
.

The brain regions most important for this interconnection include the anterior central cortex, lateral orbitofrontal cortex, and hippocampus
.

Longitudinal analysis showed that insufficient and excessive sleep duration was significantly associated with cognitive decline in participants at follow-up
.

In addition, structural equation modeling identified a unified model incorporating polygenic risk scores (PRS), sleep, brain structure, cognition, and mental health
.

Taken together, this study suggests possible genetic mechanisms and changes in brain structure that may underlie the nonlinear relationship between sleep duration and cognitive and mental health
.

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