You shouldn't stay up all night worrying about it, but a new study has found a connection between a lack of sleep and a biomolecule thought to be important in the development of Alzheimer's disease. In both humans and mice, levels of a peptide called amyloid-β rise during waking hours and decline during sleep, researchers have found. They also report that sleep-deprived mice are more prone to developing deposits of amyloid-β, called plaques, like those found in the brains of Alzheimer's patients. Although far from proven, the finding suggests that sleep disorders could be a risk factor for Alzheimer's. On...