Just one sleepless night raises levels of a protein linked to Alzheimer’s disease in the blood of young men (Benedict et al., 2020).
This suggests getting into good sleep habits at an early age may help ward off the illness.
People with Alzheimer’s have clumps of two sticky proteins –
beta-amyloid and tau – in their brains. Previous work has found that one night of sleep deprivation raises beta-amyloid levels in our brains, but less is known about tau.
Jonathan Cedernaes at Uppsala University in Sweden and his team
recruited 15 healthy young men. They measured tau levels in the
men’s blood after a full night’s sleep and after a night of no sleep.
After the sleepless night, tau levels in blood rose by 17%. After
the good night, the rise was 2%.
While it is a small study that looked only at men, the finding adds to growing evidence that people with poor sleep are more likely to develop Alzheimer’s decades later, says Cedernaes.
More research is needed to confirm that sleep deprivation increases tau in the brain, since blood levels are not necessarily indicative of amounts in the brain, says Cedernaes. And higher blood levels of tau after sleep deprivation could be a sign that the brain is clearing out the protein rather than accumulating it, he says.
The role tau plays in Alzheimer’s is unclear – it may be a side effect, not a cause. Similarly, while lack of sleep has been linked to Alzheimer’s disease, it is possible that this is an early sign of
the condition, rather than a contributing factor.
Benedict, C., Blennow, K., Zetterberg, H. & Cedarnaes, J. (2020) Effects of acute sleep loss on diurnal plasma dynamics of CNS health biomarkers in young men. Neurology. 94(11). DOI: https://doi.org/10.1212/WNL.0000000000008866.
Klein, A. (2020) Alzheimer’s Protein Rise Without Sleep. New Scientist. 18 January 2020, pp.17.