How daytime sleep can raise dementia risk

If you think you can compensate for your night’s sleep during the daytime you may be wrong, said Dr. Sudhir Kumar, a Hyderabad-based neurologist on Wednesday.

Dr Sudhir, a neurologist at Indraprastha Apollo Hospitals, in a post on X.com, said that daytime sleep is not aligned with the body’s clock and also increases the risk of dementia and other psychiatric disorders.

“Daytime sleep is lighter, since it is not aligned with the circadian clock, and hence fails to fulfill the homeostatic function of sleep,” the doctor said.

“This fact is supported by numerous studies of night shift workers, who as a group are predisposed to stress, obesity, cognitive deficits, and an elevated risk of neurodegenerative diseases,” he added.

This is because the glymphatic system, which is known to clear the brain of protein waste products, is most active during sleep. Hence when sleep loss occurs, the glymphatic system faces failure, raising the risk of dementia, explained the doctor.

“Glymphatic failure as the common pathway of dementia. Suppression or failure of the glymphatic system results in accumulation of abnormal proteins in various parts of the brain, leading to many neurodegenerative diseases, including Alzheimer’s disease (AD),” Dr Sudhir said.

Besides poor sleep quality, age, sedentary lifestyle, cardiovascular diseases, obesity, sleep apnoea, circadian misalignment, substance abuse, and depression are factors that suppress or result in failure of the glymphatic system.

“Good sleepers live longer, weigh less, have a reduced incidence of psychiatric disorders, and remain cognitively intact longer,” the neurologist said. “Habitually sleeping well at night could result in better cognitive function and reduce the risk of dementia and psychiatric disorders,” he added.