Researchers found by studying 20 healthy adults ranging from age 22 to 72, after a sleepless night that sleep deprivation can cause a build-up of the protein, beta-amyloid in part of the brain by 5%. This protein may raise a person’s risk of getting Alzheimer’s disease.
The study took place over two nights. On the first night, participants were allowed to sleep from 10 p.m. until 7 a.m.; the next evening, they weren’t allowed to get any sleep at all. Researchers scanned their brains and found an increase of this protein in two areas damaged by Alzheimer’s: The hippocampus affects memory while the thalamus serves as a relay center for sensory and motor nerve signals.
Those with mild memory loss have 21% more beta-amyloid in their brains than healthier older adults. Those with Alzheimer’s have 43% more of this protein. Similar studies have shown this with mice; this is the first research showing the same results in humans. Sleep is necessary in clearing out this protein. With sleep deprivation, it can form clumps blocking important pathways in memory. What is still unclear though, is whether one sleepless night has long-lasting effects on memory or are seen just the day after.
The study’s lead author, Dr. Ehsan Shokri-Kojori, from the National Institutes of Health in Maryland, said: ‘Often brain changes seen in animals are not replicated in humans, so this is interesting.
‘The increase in beta-amyloid we saw in the brains of people who were sleep-deprived is likely to be a harmful process.
‘A reasonable prediction based on these results would be that poorer sleep habits create a risk for Alzheimer’s disease.’
Dr. David Reynolds, chief scientific officer at the charity at Alzheimer’s Research UK, said: ‘There is growing evidence of a link between disrupted sleep and Alzheimer’s disease, but it is difficult to tease apart cause and effect to determine whether sleep problems might cause Alzheimer’s brain changes or vice-versa.
‘This very small study suggests that one night of sleep deprivation can raise levels of the hallmark Alzheimer’s protein amyloid, strengthening suggestions that sleep is important for limiting the build-up of this protein in the brain.’