Studies done in older adults suggest sleep deprivation increases the levels of tau protein in cerebral tissue. Now it appears that sleep deprivation poses the same risk to the brains of young people. Investigators in Sweden and the United Kingdom have reported that even in young healthy people, just one night of sleep deprivation increases levels of tau in the blood.
Tau is a protein found in the neurons of the brain. It can become tangled and accumulate in the brain, something seen in the brains of those with Alzheimer’s disease. These tangles can accumulate decades before the symptoms of Alzheimer’s begin to appear.
After a night of sleep deprivation, tau levels in the participants' blood rose by an average 17 percent compared to an average two percent increase after a full night of sleep.
The small, two-part study enrolled 15 healthy men with an average age of 22. Participants reported they regularly got seven to nine hours of sleep per night. The men were observed at a sleep clinic for two days and nights during both parts of the study. Blood samples were taken at night and then again in the morning. During the first part of the study, participants were allowed to get two full nights of sleep at the clinic. In the second condition, participants got one full night of sleep, followed by a night of sleep deprivation. On that night, the lights were kept on while participants were allowed to talk, play board games and watch movies.
After a night of sleep deprivation, tau levels in the participants' blood rose by an average 17 percent compared to an average two percent increase after a full night of sleep. The findings suggest that sleep deprivation can affect brain health, even in young, healthy people.
It's not clear yet if increased levels of tau in the blood mean it is being cleared from the brain, or if it is accumulating in the brain, said Cedernaes, a researcher in the department of neuroscience at Uppsala University in Sweden. Future studies will need to look further at why tau levels change, and determine how long the change lasts. Studies could also determine if these changes reflect a mechanism by which sleep deprivation increases dementia risk.
”Such studies could provide key insight into whether interventions targeting sleep should begin at an early age to reduce a person’s risk of developing dementia or Alzheimer’s disease,” Cedernaes said.