Daytime napping is common among older adults. The longitudinal relationship between daytime napping and cognitive aging, however, is unknown. A new cohort study by investigators from Brigham and Women’s Hospital found a bidirectional link between the two: excessive daytime napping predicted an increased future risk of Alzheimer’s dementia, and a diagnosis of Alzheimer’s dementia sped up the increase in daytime napping during aging. The team’s results are published in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association.