Sleep patterns have a major impact.
A recent study published in Alzheimer’s & Dementia on January 27, 2025, suggests that delays in entering the rapid eye movement (REM) sleep phase could be an early indicator of Alzheimer’s disease. REM sleep is essential for the brain to process and consolidate memories, and a delay in reaching this phase might disrupt memory storage. This disruption could also increase cortisol levels, a stress hormone that can negatively affect the hippocampus, a key brain region involved in memory.
The research specifically focused on REM sleep because it plays a critical role in storing emotionally significant memories. REM sleep usually occurs after several non-REM stages and takes around 90 minutes or more to begin, with older individuals often experiencing a delay. The study tracked the sleep patterns of 128 participants with an average age of 70, half of whom had Alzheimer’s, and the other half had mild cognitive impairment (MCI), a condition that can signal the onset of Alzheimer’s.
During overnight monitoring in a clinic, the participants’ brain activity, eye movement, heart rate, and breathing were observed. The participants were divided into two groups: those who entered REM sleep earlier and those who entered it later. The study found that those with Alzheimer’s had more frequent delays in reaching REM sleep, and they had elevated levels of amyloid and tau proteins, which are associated with the disease. Additionally, people with delayed REM sleep had lower levels of brain-derived neurotrophic factor (BDNF), a protein important for brain health that is known to decrease in Alzheimer’s patients.
Although the study shows a link between delayed REM sleep and Alzheimer’s, it does not confirm that delayed sleep causes the disease. Researchers are still unsure whether the delayed sleep is a symptom of Alzheimer’s or a contributing factor. However, the findings suggest that improving sleep quality could have potential benefits in reducing Alzheimer’s risk. Previous research has indicated that certain sleep aids, like melatonin, and medications that block substances suppressing REM sleep could lower amyloid and tau levels and possibly slow disease progression.
Experts emphasize the importance of maintaining good sleep hygiene, which includes managing sleep disorders like sleep apnea and reducing alcohol consumption. Individuals taking medications that impact REM sleep, such as some antidepressants, are advised to consult with their healthcare providers to understand the potential impact on Alzheimer’s risk. This study paves the way for further research into the role of sleep in Alzheimer’s and how interventions targeting sleep patterns could help mitigate the disease’s progression.
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