New Delhi: Disturbed sleep may compromise the brain's natural defence system through a range of biological processes, potentially increasing the risk of cognitive decline and neurological disorders, according to a new scientific review.
Researchers from Shanghai Jiao Tong University analysed existing studies and found growing evidence that poor sleep can impair the integrity of the blood-brain barrier — a highly selective structure that protects the brain from harmful substances while allowing essential nutrients to pass through.
The review, published in LabMed Discovery, examined how sleep disruption affects this protective barrier and identified several mechanisms responsible for the damage. These include oxidative stress, neuroinflammation, imbalances in gut bacteria and disruptions to the body's natural sleep-wake cycle.
The blood-brain barrier plays a crucial role in maintaining healthy brain function. When damaged, it can become more permeable, allowing unwanted substances to enter the brain and affecting the body's ability to clear metabolic waste.
Researchers noted that such damage has been linked to cognitive impairment, Alzheimer's disease and conditions affecting the brain's blood vessels and white matter.
Among various sleep disorders, obstructive *sleep apnoea showed the strongest direct evidence in humans of blood-brain barrier injury. The review suggests that repeated interruptions in breathing during sleep may contribute significantly to the breakdown of this critical protective system.
The researchers also highlighted that damage to the blood-brain barrier in the hippocampus — the brain region associated with learning and memory — could serve as an early warning sign of cognitive dysfunction.
Importantly, they found that this marker may operate independently of traditional Alzheimer's-related changes involving amyloid-beta and tau protein accumulation.
The review further assessed potential diagnostic tools, including advanced MRI techniques, and emphasised that treating the underlying sleep disorder remains the most direct strategy for protecting brain health.
However, the researchers pointed to major knowledge gaps, including the absence of validated biomarkers for blood-brain barrier damage in sleep disorders and limited evidence on whether such injury can be fully reversed after treatment.
*Sleep apnoea:
Sleep apnoea is a common sleep disorder characterised by repeated interruptions in breathing during sleep, often resulting in poor sleep quality, daytime fatigue and an increased risk of cardiovascular disease.
(With agency inputs from PTI)
