A preliminary study by researchers at Uppsala University has found that when young, healthy men were deprived of just one night of sleep, they had higher levels of tau -- a biomarker for Alzheimer's disease -- in their blood than when they had a full, uninterrupted night of rest. The study is published in the medical journal Neurology.
Tau is a protein found in neurons and the protein can form into tangles. These accumulate in the brains of people with Alzheimer's disease. This accumulation can start decades before symptoms of the disease appear. Previous studies of older adults have suggested that sleep deprivation can increase the level of tau in the cerebral spinal fluid. Trauma to the head can also increase circulating concentrations of tau in blood.