People who sleep poorly are more likely to develop Alzheimer’s disease, according to a recent study. Researchers at the National Institutes of Health found that losing just one night of sleep led to an immediate increase in beta-amyloid, a protein in the brain associated with Alzheimer’s disease. A previous study showed that chronic poor sleep may contribute to cognitive decline.
In Alzheimer’s disease, beta-amyloid proteins clump together to form amyloid plaques, a hallmark of the disease. “This research provides new insight about the potentially harmful effects of a lack of sleep on the brain and has implications for better characterising the pathology of Alzheimer’s disease,” said researcher George F Koob.
To understand the possible link between beta-amyloid accumulation and sleep, the researchers used positron emission tomography (PET) to scan the brains of 20 healthy subjects, ranging in age from 22 to 72, after a night of rested sleep and after sleep deprivation (being awake for about 31 hours). They found beta-amyloid increases of about 5% after losing a night of sleep in brain regions, including the thalamus and hippocampus, regions especially vulnerable to damage in the early stages of Alzheimer’s disease.
In Alzheimer’s disease, beta-amyloid is estimated to increase about 43% in affected individuals relative to healthy older adults. It is unknown whether the increase in beta-amyloid in the study participants would subside after a night of rest. The researchers also found that study participants with larger increases in beta-amyloid reported worse mood after sleep deprivation.
It is also important to note that the link between sleep disorders and Alzheimer’s risk is considered by many scientists to be “bidirectional”, since elevated beta-amyloid may also lead to sleep disturbances. The study appears in the Proceedings of the National Academy of Sciences.