Sleeping during daytime may increase risk of dementia: Report

Daytime sleep has always been considered a beneficial practice for its restorative effects on the body and mind. However, recently Dr Sudhir Kumar, a Hyderabad-based neurologist said that daytime sleep may increase the risk of developing dementia later in life. 

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.

In conclusion, excessive daytime sleep disrupts the body's natural sleep-wake cycle, leading to fragmented and poor-quality sleep at night. This disrupted sleep pattern can cause a build-up of harmful proteins in the brain, which is a known risk factor for dementia. Additionally, daytime sleep can also lead to a sedentary lifestyle, which is another risk factor for dementia. It is important for individuals, especially older adults, to maintain a healthy and consistent sleep schedule to reduce their risk of developing dementia.