A new study from Chinese and American researchers has revealed that taking longer to enter dream sleep might be an early warning sign of Alzheimer’s disease, offering new insights into the connection between sleep patterns and brain health.
The research, published January 27 in Alzheimer’s and Dementia: The Journal of the Alzheimer’s Association, found that individuals who took more than three hours to enter rapid eye movement (REM) sleep showed significantly higher levels of proteins associated with Alzheimer’s disease.
“The delay in REM sleep disrupts the brain’s ability to consolidate memories by interfering with the process that contributes to learning and memory,” explains Dr. Yue Leng, associate professor in the Department of Psychiatry and Behavioral Sciences at UCSF and senior author of the study. “If it is insufficient or delayed, it may increase the stress hormone cortisol.”
The study followed 128 adults with an average age of 70, monitoring their sleep patterns at the China-Japan Friendship Hospital in Beijing. The research team, led by Dr. Leng and Dr. Dantao Peng, discovered that participants who took longer to reach REM sleep had 16% more amyloid and 29% more tau – two proteins strongly linked to Alzheimer’s development.
Perhaps most striking was the finding that delayed REM sleep was associated with a 39% reduction in brain-derived neurotrophic factor (BDNF), a protein that typically shows decreased levels in Alzheimer’s patients. This substantial difference suggests that changes in sleep patterns might be more than just a symptom – they could be an early indicator of the disease process.
REM sleep, the phase when most dreaming occurs, typically begins about 90 minutes after falling asleep. During this crucial period, the brain processes emotional memories and transfers them into long-term storage. The study classified participants into two groups: those reaching REM sleep in less than 98 minutes (early group) and those taking more than 193 minutes (delayed group).
The implications of these findings extend beyond just identifying risk factors. Dr. Peng emphasizes the importance of addressing sleep-related issues that might affect REM sleep. “This includes treating conditions like sleep apnea and avoiding heavy drinking, since both can interfere with a healthy sleep cycle,” he notes.
The research team suggests that medications influencing sleep patterns might play a role in modifying disease progression. Previous studies in mice have shown that melatonin, which can boost REM sleep, may help decrease the accumulation of harmful proteins associated with Alzheimer’s. Similarly, certain insomnia medications that work by blocking REM-suppressing chemicals have demonstrated potential in reducing these harmful proteins.
For those concerned about Alzheimer’s risk, the researchers recommend discussing medications that might affect REM sleep with their healthcare providers, particularly antidepressants and sedatives known to impact this sleep phase.
The study represents a significant step forward in understanding the complex relationship between sleep patterns and Alzheimer’s disease. While more research is needed to fully understand these connections, the findings suggest that monitoring REM sleep patterns could potentially help identify individuals at risk for Alzheimer’s before other symptoms appear.
The research was supported by the Chinese Ministry of Science and Technology and the Chinese National Health Commission, reflecting growing international collaboration in Alzheimer’s research.
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