Poor sleep increases the risk of cognitive problems, an early warning sign of Alzheimer’s disease. A new study published in the journal Brain explains the reason for the link. Just one night of poor sleep can cause an increase in amyloid beta, a brain protein linked to Alzheimer’s disease. And a week of disturbed sleep can increase the level of another brain protein, tau, which has been linked to brain damage in Alzheimer’s and other neurological diseases.

 

The study was based on 17 healthy volunteers, aged 35 to 65, without sleep problems or mental impairments The participants wore activity monitors that measured the quality of their sleep for two weeks. Half of the participants were randomly selected to have their sleep disrupted on one night, while the other half slept undisturbed. A month or later, the process was repeated with the group that had uninterrupted sleep the first time. The researchers compared the participants amyloid beta and tau levels after the disrupted night to the levels after the uninterrupted night. There was a 10 per cent increase in amyloid beta levels after a single night of interrupted sleep. But one bad night did not cause an increase in tau levels.

 

However, participants whose activity monitors showed disturbed sleep for a week or more showed an increase in tau levels. We showed that poor sleep is associated with higher levels of two Alzheimer’s-associated proteins. We think that perhaps chronic poor sleep during middle age may increase the risk of Alzheimer’s later in life,” noted the study’s senior author