Poor sleep in middle age can speed up brain aging in several ways. It reduces the brain's ability to clear waste products like beta-amyloid, which is linked to Alzheimer's disease. Disrupted sleep also impairs memory and cognitive functions, resembling accelerated aging, while limiting brain plasticity, which is essential for adapting and learning. Additionally, chronic sleep issues can increase inflammation, potentially damaging brain cells and accelerating the aging process. Hormonal changes resulting from poor sleep further disrupt processes that support brain health, contributing to cognitive decline over time.