Summary: Delayed rapid eye movement (REM) sleep may be an early indicator of Alzheimer’s disease. Researchers found that participants with delayed REM sleep had higher levels of toxic proteins associated with Alzheimer’s and reduced levels of brain-derived neurotrophic factor (BDNF), which supports memory.

Delayed REM sleep disrupts memory consolidation and increases stress hormone levels, which can impair the hippocampus, a critical brain region for learning and memory. The findings emphasize the importance of healthy sleep habits and suggest that treatments targeting sleep patterns may influence Alzheimer’s progression.