While you sleep, your body repairs itself through a myriad of processes. When you don’t get enough sleep, these repair processes are interrupted. The human brain requires time to repair itself as well -- ideally more than 6 hours a night. When it is unable to, the brain finds a way to work around its limitations.
Cleaning cells called astrocytes act as a type of maintenance unit, focusing on connections that become weak or start to break down. Researchers found that astrocyte activity increased in sleep deprived mice. Worn out synapses were the primary target. (1)
Even though this information may be scary, researchers say this activity is a good thing. If you think of the brain as a machine, it makes sense that an overworked piece of equipment would require more upkeep. This might be helpful in the short term, but could increase the risk of dementia in the long run
Unfortunately, not every finding in the study was a good one. The same sleep deprived brains showed increased activity in the types of brain cells associated with Alzheimer’s disease.
Individuals with metabolic syndrome who slept less than 6 hours a night were also found to be at a higher risk of death from heart disease or stroke.