Does Sleep Function to Remove Waste from your Brain?
Although this "news" came out in 2013, I think that it is still an interesting and relevant article for others to read: http://www.bbc.com/news/health-24567412
Researchers from the University of Rochester conducted a series of studies with mice and gained insight into what is possibly an essential reason for why we sleep. The authors were motivated to better understand the reasoning behind this core process. They wanted to know why animals seem required to engage in a process that leaves them so vulnerable to predators. Through several studies with mice, the authors deduced that the ventricle and aqueduct system that moves cerebrospinal fluid (CSF) through your brain is especially active during sleep and functions as a "waste removal system". The scientists even observed that cells seem to shrink down in size to better allow the CSF to flow between neurons. The reason that this happens during sleep instead of waking is suggested to be because the process is still energy-consuming and it would be taxing and inefficient to do it while your brain is carrying out other energy-requiring information processing. The overall magnitude of this waste removal system's function is quite large indeed. The "glymphatic system" (a term created by these authors) is apparently about 10 times more active during sleep than during waking. The last important point that the authors bring forth is the relationship between this waste removal system and neurodegenerative cognitive diseases like Alzheimer's and Parkinson's. These diseases are characterized by the build-up of proteins (e.g., amyloid-beta plaques), which are often recycled during normal sleep states.
The results from these studies are interesting for several reasons. It has long been unclear as to why we sleep. Many researchers and great thinkers have suggested a variety of possible functions, but the true reason why we spend 1/3 of our lives in a sleep-state has mostly been unclear. The findings from this study finally provide core insight into one of the essential functions that sleeping might have. These findings make sense especially when you consider the subjective experience of not getting enough sleep. Your brain never really feels as though it is functioning at its optimal level after a night of inadequate sleep. This subjective experience appears to have a clear physiological root, because your brain has not cleared away all of the toxins that have built up during this time period. There are also clear and important implications from these findings. Notably, college is a time period where people tend to drastically decrease the average amount of sleep they get a night, but while they are also increasing the amount of cognitive demand on their brains. Getting additional sleep likely has clear benefits for enhanced cognitive processing. The link to neurodegenerative diseases ii especially important since it can lie a pathway towards prevention or novel treatment methods.
Researchers from the University of Rochester conducted a series of studies with mice and gained insight into what is possibly an essential reason for why we sleep. The authors were motivated to better understand the reasoning behind this core process. They wanted to know why animals seem required to engage in a process that leaves them so vulnerable to predators. Through several studies with mice, the authors deduced that the ventricle and aqueduct system that moves cerebrospinal fluid (CSF) through your brain is especially active during sleep and functions as a "waste removal system". The scientists even observed that cells seem to shrink down in size to better allow the CSF to flow between neurons. The reason that this happens during sleep instead of waking is suggested to be because the process is still energy-consuming and it would be taxing and inefficient to do it while your brain is carrying out other energy-requiring information processing. The overall magnitude of this waste removal system's function is quite large indeed. The "glymphatic system" (a term created by these authors) is apparently about 10 times more active during sleep than during waking. The last important point that the authors bring forth is the relationship between this waste removal system and neurodegenerative cognitive diseases like Alzheimer's and Parkinson's. These diseases are characterized by the build-up of proteins (e.g., amyloid-beta plaques), which are often recycled during normal sleep states.
The results from these studies are interesting for several reasons. It has long been unclear as to why we sleep. Many researchers and great thinkers have suggested a variety of possible functions, but the true reason why we spend 1/3 of our lives in a sleep-state has mostly been unclear. The findings from this study finally provide core insight into one of the essential functions that sleeping might have. These findings make sense especially when you consider the subjective experience of not getting enough sleep. Your brain never really feels as though it is functioning at its optimal level after a night of inadequate sleep. This subjective experience appears to have a clear physiological root, because your brain has not cleared away all of the toxins that have built up during this time period. There are also clear and important implications from these findings. Notably, college is a time period where people tend to drastically decrease the average amount of sleep they get a night, but while they are also increasing the amount of cognitive demand on their brains. Getting additional sleep likely has clear benefits for enhanced cognitive processing. The link to neurodegenerative diseases ii especially important since it can lie a pathway towards prevention or novel treatment methods.
In my motivation class, we learned that an early theory of the function of sleep was for safety. Early ancestors fell asleep at night in order to protect themselves from the dangers present at night fall. This eventually evolved into a 24 hour sleep cycle. This theory, though reasonable, doesn't explain why our bodied feel depleted with lack of sleep. Another theory that was thrown out was closely tied to theories questioning why we have dreams. Psychologist theorized that early ancestors dreamed as a way of practicing how to hunt without putting their physical bodies in danger. This theory however doesn't provide has little evidence.
ReplyDeleteThis new research provided a more sensible explanation for the purpose of sleep but I think the research shouldn't stop at the neurological level. Our physical bodies also benefit from sleep. We sleep when we are sick or physically drained or after a huge meal. I would like to see more research conducted to provide a connected explanation for why we sleep.
Sleep is one of my favorite activities. As a college student, I do not get enough of it. I think it is exciting to finally having an understanding of the mechanism or in this case a system (glymphatic) that is essential to human existence. Sleep is important to the body as well as it can lead to aging of the skin, pseudo-depression (not diagnosed), and even lowers one's sex drive. Everyone loves sleep, but more importantly the body loves sleep too. I think that more students and working people should be aware of the importance of proper sleep. I was also wondering the reason behind being groggy when you wake up from an adequate amount asleep and is there, statistically, the perfect amount of sleep. These are questions just to keep the juices flowing. Thank you for sharing Dr. McGinley.
ReplyDeleteSource from: http://www.webmd.com/sleep-disorders/excessive-sleepiness-10/10-results-sleep-loss?page=2
This article nailed it right on the head, especially with the college part. Every college semester, the amount of time I sleep tends to go way down! This semester I'm sitting at an average of 4.5-5.0 hours of sleep a night due to my work/school schedule. On days where I don't get the amount of sleep that my body needs I feel very clogged up and just clouded cognitively. This might be because my body hasn't had the chance to remove all the cognitive and other forms of waste. Furthermore, I tend to get sick quicker which then requires and forces me to take a few days off and just sleep. This could be again because my body isn't getting the required amounts of sleep that it needs to properly clean and keep my body running.
ReplyDeleteThis article has great information about the sleep wake cycle and the usefulness of sleep. I remember discussing this in class and since then I have had a new understanding of the importance of sleep but ironically I sleep less since then. This article relates particularly to my life because I work two full time jobs, one at night and one during the day so the amount of sleep i get is slim to none except on Thursdays and Sundays which are my off days. I find that since taking on a second job and decreasing my sleep drastically, it is a lot harder to keep up with my school work and excel as much as I usually do in my academics. When I go to study, I am usually really tired and I do so on purpose because in another article I read for another class, it talked about how sleep can help you to retain information and when you sleep after looking at it, it is more likely to stay in long term storage and be more clear, hence the term "sleep on it". I also agree with what Amber said in the previous comments that there is definitely something different when you sleep for long periods of time and your body seems to almost be just as tired as when you went to sleep. I think this has less to do with the clearing of toxins as that happens naturally when you sleep but more so to do with the body itself and perhaps not being adjusted to the amount of sleep you had. Since our bodies tend to maintain homeostatic states, perhaps when you sleep too much, there is an access of a specific neurotransmitter or chemical imbalance that is trying to signal to your body to return back to its set point that is somehow related to sleep or rest.
ReplyDelete