The brain doesn’t just rest during sleep—it actively clears out waste that can damage brain cells. This crucial process, known as glymphatic clearance, relies on the movement of cerebrospinal fluid to wash away harmful proteins linked to neurodegenerative diseases. A recent study found that synchronized fluctuations in norepinephrine, blood volume, and cerebrospinal fluid are key drivers of glymphatic clearance during deep sleep, but some popular sleeping pills disrupt this process.

The researchers tracked blood and cerebrospinal fluid dynamics while mice slept naturally. Then, they examined how zolpidem, commonly known as Ambien, affected these dynamics during sleep.

They found that norepinephrine fluctuations triggered by the brain’s locus coeruleus drove rhythmic changes in blood vessel size. This facilitated the movement of cerebrospinal fluid into the brain and the removal of waste products. However, zolpidem disrupted norepinephrine activity, reducing cerebrospinal fluid flow and hindering this waste removal process.

These findings suggest that the brain’s waste removal system relies on a delicate balance of norepinephrine and blood vessel activity. Sleep aids like zolpidem disrupt this process, potentially contributing to neurodegenerative diseases like Alzheimer’s. Learn more about the effects of sleep aids like Ambien in this episode featuring Dr. Matthew Walker.