Everyone knows they need to sleep. Now, scientists have discovered how the brain flushes toxins out of our brains while we are asleep. Find out what this means for our health and well being.
We just turned the clocks back to move out of Daylight Saving Time for the winter. As a night person, I enjoy the extra hour of sleep we get. However, many people feel disoriented whenever we change the clocks. It messes with our sleep patterns, and sleep is vital for our well being. Like Kate Bush put it, we all need to “sleep and dream of sheep.”
I have sleep apnea. That means that when I fall asleep, and the muscles in my throat relax, my airway narrows when I breathe in. I don’t get enough air, and that reduces the oxygen in my blood. My brain can tell I’m not breathing, so it wakes me up and reopens my airway. In the morning, I have no idea this went on, even though it happens over and over every night.
The good news is that there is a treatment for it. I use a machine called a CPAP at night. It gently pumps air into my airway and creates enough pressure to keep it open. That way, I sleep soundly right through the night.
How critical sleep is to our health
I didn’t realize it then, but before I got my sleep apnea under control, I was a menace to society. I fell asleep in meetings without even realizing it, and I definitely should not have been driving. All of which serves as a reminder of how critical sleep is to our health.
We spend about a third of our time asleep. People used to think that our brains and the rest of our bodies shut down during sleep, but that’s not the case. We now know that all sorts of activities go on while we sleep.
We have two kinds of sleep, rapid eye movement (REM) sleep and non-REM sleep. They go in cycles through the night. During non-REM sleep, we repeatedly go through three phases called N1, N2 and N3.
REM sleep and non-REM sleep
Stage N1 is that familiar sensation when we feel drowsy or “half-asleep.” Everything just starts to slow down during this phase. As we know, it’s a light form of sleep, and any little thing can jolt us back to an awake state. An uninterrupted N1 stage is relatively brief, typically lasting only five or ten minutes.
In stage N2, things slow down even more, and our eyes stop moving. This usually lasts between 10 and 25 minutes. We’re still sleeping reasonably lightly, but we spend more time (perhaps 55% of the total) in N2.
Sometimes stage N3 is called the delta stage. It lasts between 20 and 40 minutes during each sleep cycle. This is when we are fast asleep. It’s also the kind of sleep we need the most to feel healthy.
the kind of sleep we need the most
Our vital signs slow down to the lowest levels. If someone manages to wake us up out of N3 sleep, we feel groggy and “out of it” for a while. This is the phase where we can have nightmares and talk or walk while unconscious.
It takes us about an hour and a half to get into the REM stage. The first round lasts about ten minutes, and later rounds gradually go longer. Someone watching us can see the telltale rapid eye movements under our eyelids.
Nobody knows why we move our eyes like this, but it seems to have to do with dreaming. We have our pleasant and vivid dreams during REM.. Most of don’t remember these dreams unless we are awakened during a REM cycle. Our brains also do some data maintenance during REM, shifting information into our long term memories.
Insomnia weakens our immune systems
We need sleep for neural plasticity, our ability to adapt and change when unique situations arise. When we’re sleep-deprived, it impairs our memory functions. It can also lead to or aggravate depression, seizures, high blood pressure and migraines. Insomnia weakens our immune systems, so we get sick more easily.
We can’t function without sleep. It’s crucial for our thinking processes, and it’s how our body takes care of itself. A new study published in the November 1 issue ofScience outlines another reason why sleep is vital for our long term well being.
During the night, our brains get washed out every twenty seconds with waves of something called cerebrospinal fluid (CSF). This helps us to get rid of toxins like amyloid-beta proteins in the brain, which can get stuck and cause Alzheimer’s disease. It’s hard to tell for sure, but these waves of CSF seem to be coordinated with electrical brain waves and rhythms of cerebral blood flow.
Our brains get washed out every twenty seconds
Researchers led by Nina E. Fultz of Boston University looked at lab results for studies done on animals. They showed that CSF could flush amyloid-beta proteins out of the brain. The team wanted to confirm that the same process goes on in humans during sleep.
The scientists did sleep studies, including MRI scans, on 13 young, healthy human subjects. They used a form of rapid functional MRI to monitor the waves of CSF flowing into and out of the subjects’ brains during the non-REM stages. What they found was impressive. Not only could they see the waves that they were expecting, but they were remarkably robust.
Laura Lewis, a neuroscientist and engineer at Boston University, toldScience News, “I’ve never had something jump out at me to this degree,” she says. “It was very striking.”
“It was very striking.”
There is always an oscillating flow of CSF running through our brain when we are awake. However, as Lewis puts it, “The waves we saw during sleep were much, much larger, and higher velocity,” Lewis says.
The scientists looked at young, healthy people. They say that the next step is to study these powerful waves of CSF in people living with Alzheimer’s. It’s hard to say what comparing the two groups might tell us, but it would likely explaIn characteristics of the disease we don’t know about now. The more we learn, the closer we get to treatments or even a cure.
We always have more to learn if we dare to know.
Johns Hopkins Medicine
Coupled electrophysiological, hemodynamic, and cerebrospinal fluid oscillations in human sleep
And Dream of Sheep