A US clinical-pathologic cohort study found that more frequent morning naps were linked to a higher risk of developing Alzheimer’s dementia. Additionally, more naps in the early afternoon and more consistent nap patterns were linked to lower levels of Alzheimer’s pathology. The study analyzed data from 936 older adults (aged 56–99; 77% female) to assess incident Alzheimer’s dementia, and from 320 deceased participants (aged 71–105 at death; 70% female) to examine Alzheimer’s pathology. Using actigraphy, the proportions of naps taken were measured in the morning (9–11 am) and early afternoon (1–3 pm), along with the intraindividual variability of nap duration. Neurological assessments were conducted at baseline in 2005 and annually for up to 17 years, and in deceased participants, brain tissue was examined for amyloid β and neurofibrillary tangles. Aging was associated with more naps in the early afternoon. More frequent morning naps were associated with a higher risk of Alzheimer’s dementia, while more early afternoon naps were linked to reduced amyloid β levels. Additionally, greater variability in nap duration was associated with increased amyloid β and neurofibrillary tangles. These findings suggest that both the timing and consistency of daytime napping are important factors in Alzheimer’s disease risk and pathology, highlighting the value of multidimensional assessments of sleep behavior for identifying individuals at risk and guiding interventions to support cognitive health. Source: https://www.nature.com/
