A new study in mice has shown that chronic sleep disruption accelerates the progression of tau pathology, a hallmark of Alzheimer disease and frontotemporal dementia. Researchers examined the effect of chronic short sleep in mice with a Pro301Ser mutation in MAPT (which encodes tau) that is associated with tauopathy in humans. Chronic short sleep in early adulthood hastened the development of motor impairment, increased the rate of neuronal loss and raised the levels of pathogenic tau oligomers in the mice. The increased levels of tau oligomers were sustained after sleep disruption ceased, even after a 6-month recovery period. The results mirror previous findings that amyloid-β levels and plaque burden are increased by sleep loss in mice, and suggest that sleep habits in early life affect subsequent neurodegeneration.