Extreme sleep: Change in durations may affect brain health in later life

A new research study led by Brigham and Women’s Hospital (BWH) published in The Journal of the American Geriatrics Society in May, shows an association between midlife and later life sleeping habits with memory; and links extreme sleep durations to worse memory in later life. The study suggests that extreme changes in sleep duration from middle age to older age may also worsen memory function.

“Sleep Duration In Midlife and Later Life In Relation to Cognition: The Nurses’ Health Study,” led by Elizabeth Devore, ScD, instructor in medicine in the Channing Division of Network Medicine at BWH found that women who slept five or fewer hours, or nine or more hours per day, either in midlife or later life, had worse memory, equivalent to nearly two additional years of age, than those sleeping seven hours per day. Women whose sleep duration changed by greater than two hours per day over time had worse memory than women with no change in sleep duration.

This study was the first to evaluate associations of sleep duration at midlife and later life, and change in sleep duration over time, with memory in 15,263 participants of the Nurses’ Health Study. Participants were female nurses, aged 70 or older and were free of stroke and depression at the initial cognitive assessment.

“Given the importance of preserving memory into later life, it is critical to identify modifiable factors, such as sleeping habits, that may help achieve this goal,” Devore stated. “Our findings suggest that getting an ‘average’ amount of sleep, seven hours per day, may help maintain memory in later life and that clinical interventions based on sleep therapy should be examined for the prevention of cognitive impairment.”

Specifically, researchers report that:

  • Extreme sleep durations may adversely affect memory at older ages, regardless of whether they occur at mid-life or later-life.
  • Greater changes in sleep duration appear to negatively influence memory in older adults.
  • Women with sleep durations that changed by two or more hours per day from midlife to later life performed worse on memory tests than women with no change in sleep duration, equivalent to being one to two years older in age, compared to those whose sleep duration did not change during that time period.

“These findings add to our knowledge about how sleep impacts memory,” said Devore. “More research is needed to confirm these findings and explore possible mechanisms underlying these associations.”


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91 thoughts on “Extreme sleep: Change in durations may affect brain health in later life”

  1. As many of you have pointed out, too little sleep is bad because when you don’t go into REM sleep, your brain isn’t able to re-learn and store what you learned through the day (If anyone would like to know more about REM sleep, you can watch Vsauce’s video “Why do we dream?”).
    I might have an answer to the question of why too much sleep can be bad for you. As Jacques – 14105293 said, the article talks about changes in sleep duration and I am inclined to agree that this must play a role in affecting one’s memory, although I could not strictly find any evidence elsewhere. BUT
    Too much sleep can be a medical disorder that’s called hypersomnia. This disorder causes extreme sleepiness during the day and long periods of sleep at night. With this disorder, taking a nap doesn’t relieve the sleepiness and the symptoms include memory problems. This makes sense, because when you feel groggy and tired, you don’t focus. If you don’t focus, then of course memory will be negatively affected.
    It must be noted that not everyone who sleeps for longer periods at times has hypersomnia. As an article on WebMD points out: “there are people who simply want to sleep a lot.” The main idea seems to be that when you sleep too much or too little, you slow down your brain, you feel tired and you don’t focus and this leads to a weakened memory.

  2. I agree that sleep is an important aspect in your everyday life and that it is important to maintain your sleeping pattern or rather to keep it constant as you get older ! But then again I believe that it is almost impossible to maintain your sleeping pattern as you get older due to a ‘busy’ life. Luckily our body’s are magnificent and capable of adapting to changes that occur !

  3. well this is very interesting maybe because our sleeping duration change every now and then as we move to the next step of depending on the field or career you are in. For example its obvious that when you move fro high school to university you will definitely change your sleeping duration because of the amount of work, then when you get a holiday you want to rest meaning you change your sleeping duration again. So i guess there’s nothing much we can do about this but since we now know the effects we can at least try to maintain the same kind of duration we have most of the time.

  4. Patricio Francisco (u14263272) – “it still leaves me confused as to why more than 9 hours of sleep will affect a persons memory negatively. How can this be explained?”

    I agree with you,the article is not clear on this. I understood the following “slept five or fewer hours, or nine or more hours per day” to mean that some nights they slept 5 or fewer hours and then some nights 9 or more hours, seeing as the article is talking about changes in sleep duration. So it’s the change in sleep durations that affect memory. I hope that helps.

    14105188 – Thank you for answering my question.
    As we get older, our bodies and brains become less resilient to changes in our lifestyle. Using that reasoning, it makes sense that it wouldn’t affect younger people as much because their bodies can still compensate for the changes in sleep durations.

  5. This blog was interesting to read. Our brains naturally weaken as we get older and our sleep quality decreases. Slow waves that are generated in a brain region called the medial prefrontal cortex (mPFC) is a sign of age-related deterioration. Deep sleep helps the brain store and recall new information, that’s why we need up to eight hours of sleep a night. As we get older the quality of our sleep stops the brain from saving any new memories. This could be another reason for memory loss in later life.

  6. I feel that “Jacques – 14105293” has the most logical explanation. When a person is deprived of sleep, the body will first make up the “deep sleep” component of your sleep at the expense of REM (Rapid Eye Movement), where REM is responsible for processing information and storing memory. Thus, when a person is deprived of sleep for long periods, over time it is more probable to have a detrimental affect on memory since the REM component of sleep is reduced over time. However, while this seems to answer why less than 7 hours sleep affects memory, it still leaves me confused as to why more than 9 hours of sleep will affect a persons memory negatively. How can this be explained?

  7. It has been very interesting reading all the comments left by previous readers. Sleep is one of the most vital actions of life. In our early stages of life, lots of sleep is needed due to the fact of internal changes within the body and growth. This is why at least 8 hours of sleep has always been emphasized by many educational workers as well as pediatricians. As our bodies start to reach maturity less sleep is required and by the time university comes, most students are able to survive on 6 hours sleep during the week.
    This is why I believe sleeping routine changes at a young age are not as much a factor as they are as people age into the latter stages of life.
    Hopefully future studies can zone in on certain reasons as to why the memory process is affected as age increases. I think the results will be very interesting and more complex than once thought.

  8. Although, the information posted in the blog is quite informative, I think this information is quite “one-sided” in a sense that it only takes into consideration the negative impacts of changes in sleep patterns. We should also take into consideration that for other individuals, changes in sleep patterns can also result in very positive impacts.In Agreement with ‘14057192 Trichard’, we should also take into consideration that we are different and ours bodies react to changes such as changes in sleep patterns differently

  9. Although, the information posted in the blog is quite informative, I think this information is quite “one-sided” in a sense that it only takes into consideration the negative impacts of changes in sleep patterns. We should also take into consideration that for other individuals, changes in sleep patterns can also result in very positive impacts.In Agreement with ‘14057192 Trichard’, we should also take into consideration that we are different and ours bodies react to changes such as changes in sleep patterns differently.

  10. What is interesting to note is that this research concluded these sleep patterns effect individuals in later stages of life.
    The same way we neglect to take care of our bodies at a young age – with smoking, no exercise and a lot of junk food- has a massive effect on our physical well being now, as well as in later stages. Yet this research only covered the effect sleeping patterns have on cognitive function at a later stage, but as some commentators have already pointed out, they can feel the effects of changes in sleep patterns already.
    Research like this is quite interesting as it just reinforces the point that our bodies work optimal in set patterns.

  11. I found this blog entry very interesting but I would like to know why the research is only applicable to people in their midlife and after? What about younger people like students? Students definitely don’t get 7 hours of sleep every night. How would that influence their memories?

  12. I, an individual recently suffering from mild insomnia, find this article really intriguing! in relation to my personal situation, of merely four hours of sleep a night, this article adds as evidence to the result of my lack of sleep.
    In high-school; including extensive athletics training and cardiac-exerting sports, I was able to sleep at the least six hours a night. I managed to excel in my sport, achieve high academics and personally focus for many continuous hours, recalling majority of the information I had learned.
    Now that I am in Varsity and waste two hours of my day driving and spend the rest in lectures, I don’t have the amount of time to participate in as many sports as I previously did, however, without the excessive exertion I find it difficult to fall asleep.
    The lack of sleep has intervened in my studying capabilities tremendously, though I am not tired, I find it extremely difficult to study and worst of recall the knowledge that I thought I had successfully absorbed.

    I have taken a liking to this topic and look forward to further tests and research that needs to be done.

  13. I found this article very informative as I have heard of research about sleeping patterns before but have never heard of exactly how it affects the mind. I now see that sleeping patterns are very important in regard to cognitive function and that the topic should not be taken lightly if a person is serious about their mental health.

  14. Good point, 14054672, findings like this should be made more public, so people can make better decisions about their health.

    The premise is confusing, but it seems to fit with the idea that in most areas, the human body performs at its best when it fits into a routine. Routine gives the body a framework with fewer variables, allowing it to optimize certain processes. By varying the duration of sleep, the body’s circadian rhythm is constantly changing, increasing the variables that the brain has to deal with.
    It is believed that dreams are a necessary part of committing short-term memory to long-term memory. As dreams occur mainly during REM phase of sleep, affecting this will theoretically affect long-term storage of information. With a varying sleep duration, the body is constantly having to adjust its sleep cycles to account for more or less time in REM sleep.

    Does anyone have ideas as to why this could affect older people more?

  15. I find this very interesting and I am quite grateful that I read it. I tend to change the amount of sleep I get, often by more than 2 hours difference and I have already noticed that people remember things that I could almost swear never happened because I cannot recall it at all. I definitely have noticed that even if I get 10 hours of sleep my memory is just as hazy as if I had 4 hours of sleep and I do believe that 7 to 8 hours of sleep is always a safe amount to stick with. However I have noticed that although 7 hours is enough for one person, it can also be too much or too little sleep for other people. For example my sister cannot function unless she gets at least 9 to 10 hours of sleep while my brother is at his optimum with 5 hours of sleep.

  16. I find this article very interesting, especially since the topic is applicable to everyday life. Anyone can read the article and the reflect on his or her own sleeping patterns, thinking about the impact it might have later in life.

    I believe that studies such as these should be made more public. The results can change the way people view the importance of sleep, and in today’s rushed lifestyle it is important since sleep is sometimes seen as a time waster.

    The article is interesting, yet i struggle to grasp any solid facts. I agree with Ms Venter. How does too much or too little sleep affect memory? And what happens in the brain, specifically?

  17. The study surely indicates that memory loss would happen over an extended period of time with sleep deprivation and also too much sleep. But this does not give a clear indication to why the candidates had a loss of memory as they got older. I believe that further study should be induced to determine whether the cycle through which the human brain goes may also affect this memory loss as women age. Other things may also affect this memory loss in the women. Isn’t there a way to do a better and further study to actually keep these variables in mind that may also cause memory decay?

  18. This is an interesting finding, but it contradicts what most people have been told about how we need eight hours of sleep. But it is beneficial as now one can be aware of the significance for proper sleep, and how proper sleep result in one having a good memory.
    we all know that having a good memory is something which has a significant impact on one’s life as you have to remember plenty of things that happen around one’s life.

  19. Sleep is very important. It helps the human body rest and repair damaged cells. Sleep also lets the brain rest. The brain needs sleep to be able to function at its best. So there is no doubt that changing one’s sleep pattern can lead to unexpected side effects. The amount of sleep that is needed by one’s, depends on many factors and it also depends on personality. The basal sleep need is the amount of sleep that one’s body needs regularly to perform at its best. This is the amount of sleep that an one can not go without. There is another factor that also determines the amount of sleep that an one needs and it is called the sleep debt. This is the amount of sleep that one must catch up, because this sleep was lost, due to external factors that made one lose sleep. Sleep is important for one to maintain good health, but how does changing one’s sleep pattern affect one’s memory to such a degree that one loses some cognitive function?

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