A good night's sleep may be essential to brain health, say Swedish researchers who found depriving healthy young men of a night's sleep increased blood concentrations of brain molecules to levels seen in brain damage.
The researchers, from Uppsala University, report the findings of their small trial, which was funded mostly by the Swedish Brain Foundation (Hjärnfonden) and Novo Nordisk Foundation, in the latest online issue of the journal SLEEP.
Lead investigator Christian Benedict, a sleep researcher at Uppsala's Department of Neuroscience, says:
"We observed that a night of total sleep loss was followed by increased blood concentrations of NSE and S-100B. These brain molecules typically rise in blood under conditions of brain damage. Thus, our results indicate that a lack of sleep may promote neurodegenerative processes."
Sleep deprivation linked to higher levels of brain damage molecules
For their study, the team recruited 15 normal-weight, healthy young men to spend 2 nights in a sleep laboratory.
On one of the nights, the participants were totally deprived of sleep, and on the other night, they slept normally for about 8 hours.
Before and after each night, the men gave fasting blood samples, from which the researchers could measure blood levels of the brain molecules neuron-specific enolase (NSE) and S100 calcium binding protein B (S-100B).
These molecules are normally found in the cell matter of neurons (the workhorses of the central nervous system) and glia cells (the cells that support neurons), which together make up brain tissue.
Raised levels of these molecules in the blood is thus usually a sign of damaged brain tissue, or that something has gone wrong with the blood-brain barrier, or both.
The results showed that total sleep deprivation increased levels of NSE and S-100B by around 20%, compared with levels measured after a night of sleep.
Good night's sleep 'may be critical for healthy brain'
Christian Benedict says:
"In conclusion, the findings of our trial indicate that a good night's sleep may be critical for maintaining brain health."
He and his colleagues suggest further studies should now be done - where both blood and spinal fluid samples are used - to find out whether the raised levels of brain molecules really are due to brain cell damage, blood-brain barrier damage, or "is just a consequence of increased gene expression in non-neuronal cells, such as leukocytes."
Meanwhile, in another recently published study, researchers from the Johns Hopkins Bloomberg School of Health suggest that lack of sleep may increase risk of Alzheimer's disease.
In a group of older adults free of dementia, they found shorter overall nights' sleep duration and poor sleep quality were linked to increased brain build-up of beta-amyloid protein, which is a hallmark of Alzheimer's disease.