Did you know your brain has a lymphatic system (aka waste-disposal system) of its very own? It’s called the glymphatic system and it activates at night while we sleep (the opposite of the lymphatic system that’s more active in the day).
I’m just mentioning it now because I’ve had this conversation twice this week explaining the importance of sleep – always – but particularly in peri-menopausal women who suffer from insomnia. Getting a good night’s sleep is essential for our long-term brain health, so we really need to make it a priority. I can share some tips on how to do just that in the next few days. Here’s an interesting study that looks at the effect of sleep on glymphatic drainage:
For the data nerds, it’s worth taking a look at the study – but here’s essentially what it says…when we fall asleep, our brain stops paying as much attention to the outside world and switches to ‘maintenance’ mode. During sleep, the waste from the brain is ‘flushed’ out using a system called the glymphatic system. However, until recently, scientists weren’t sure exactly what controls this cleaning process.
In this study, researchers used advanced technology to track different signals in the brain during non-REM (NREM) sleep. They found that norepinephrine (a brain chemical related to alertness), blood flow in the brain, and cerebrospinal fluid (CSF) movement were all key for waste removal.
When they used light to stimulate a specific brain region called the locus coeruleus (which affects norepinephrine levels), it changed the way blood vessels pulsed and how CSF flowed in the brain. They also found that making blood vessels pulse more strongly helped CSF flow into the brain, acting like a pump to push waste-clearing fluid through.
On the other hand, when they gave the common sleep medication “zolpidem”, it reduced norepinephrine fluctuations and slowed down the brain’s cleaning system. This suggests that norepinephrine and blood vessel movement are essential for clearing out waste during sleep.
In short: the brain’s waste-clearing system (glymphatic) works best when norepinephrine levels rise and fall in sync with blood flow and CSF movement during DEEP sleep. Medications that interfere with this rhythm may slow down this cleaning process.
