Daytime napping and Alzheimer's dementia: A potential bidirectional relationship

https://alz-journals.onlinelibrary.wiley.com/doi/full/10.1002/alz.12636

by alwillis • 4 years ago

90 33 4 years ago

alz-journals.onlinelibrary.wiley.com

hindsightbias• 4 years ago

So is there a higher rate in EU countries with afternoon naps?

ILMostro7• 4 years ago

Is there a reference to siestas?

tluyben2• 4 years ago

Not many people use their siesta to actually nap though anymore: maybe in august when it is 40+ Celcius it goes up but that is a few weeks a year and tourists basically pass out then too from too much booze and food around siesta time.

inopinatus• 4 years ago

Sleeping in your car isn’t quite as popular in Europe.

qiskit• 4 years ago

Wondering this myself. I remember reading ( not too long ago ) that europeans lived longer and had better mental health because they napped more than americans. Wasn't it even encouraged to take naps at work for better mental function.

WalterBright• 4 years ago

This isn't new, a decade ago I read that Alzheimers patients sleep quite a bit more than normal. I suspect this is the brain trying to rid itself of what is causing the Alzheimers.

tinyhouse• 4 years ago

The research about napping is conflicted. If you like napping don't worry about it too much. Do what works for you.

We know there are many factors here. Maybe older people who nap more have less hobbies and use their brain less (e.g., if you still work or volunteer daily you don't have time to nap). Maybe they take more pills and have other health issues that make them more sleep during the day. Who knows. Too many possibilities.

aurora72• 4 years ago

A drug called Alprazolam or better known as Xanax drives the patient who takes it to sleep excessively during daytime. I've got two acquaintances, who take those pills and they sleep quite often during the day.

thevagrant2• 4 years ago

It's interesting and is something that crosses my mind when considering any kind of medication. what are the long term consequences of taking this?

I haven't taken xanax but I guess present day quality of life (for some) may be more important than unforseen long term consequences. It would be nice to know for sure though.

threads22• 4 years ago

Maybe not for long - tolerance builds up rapidly (and maybe permanently?) to the sleep-inducing effects of benzos.

That's why they're not recommended as a long-term sleep aid.

https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=benz...

hyperpallium2• 4 years ago

Is there any evidence here beyond correlations?

dakial1• 4 years ago

This was my doubt also. Couldn't find anything indicating a causal link, so this is not so useful in the end

avazhi2• 4 years ago

Classic correlation =/ causation problem.

If you are napping during the day, it's probable that you didn't sleep well or enough the night before. We know that, amongst other things, sleep is absolutely necessary to clear out toxins that build up in the brain during one's waking hours, and we know that people who get less than 7 hours of sleep per night are themselves at a significantly heightened risk of neurodegenerative diseases. The studies behind that particular stat strongly suggest causality - I don't have the paper handy atm but they've done experimental studies where they've taken the experimental group of rats and prevented them from sleeping, as opposed to this study which is simply observational. With the group of rats that are chronically sleep deprived by the researchers, they are significantly more likely to develop neurodegenerative disease.

I wouldn't draw much from this paper, aside from being astounded that a team of scientists wrote and published it without apparently seriously considering the basic and frankly obvious causality issue that an average first year science student would be expected to notice.

pengaru• 4 years ago

My father snored loudly all my life and as he grew elderly (and sleep apnea awareness/treatments increased) it became glaringly obvious he suffered from sleep apnea and would literally choke himself awake repeatedly throughout the night. Of course he had a tendency to fall asleep watching tv for lack of any restful sleep overnight.

I think it goes without saying there was a psychological effect, it's too complicated with many factors I don't even attempt to link specific effects. But I'm confident the sleep situation wasn't doing him (and his family) any favors.

Tenoke2• 4 years ago

We know that, amongst other things, sleep is absolutely necessary to clear out toxins that build up in the brain during one's waking hours, and we know that people who get less than 7 hours of sleep per night are themselves at a significantly heightened risk of neurodegenerative diseases.

We know that? Because meta-analyses suggest that at even 6 hours you have less all-cause mortality than at 8 hours of sleep[0] and I'm yet to see systematic reviews/meta-analyses suggest that going under 7 hours is as bad as pop science claims.

0. https://guzey.com/files/books/why-we-sleep/shen2016.jpg from Shen X, Wu Y, Zhang D. Nighttime sleep duration, 24-hour sleep duration and risk of all-cause mortality among adults: a meta-analysis of prospective cohort studies. Scientific Reports. 2016 Feb 22;6:21480

derefr2• 4 years ago

that at even 6 hours you have less all-cause mortality than at 8 hours of sleep[0]

Well, yeah; if you're sleeping more than 7 hours of sleep per night, it's likely because you're unhealthy somehow, such that your CNS takes longer than normal to clear out a sufficient amount of gunk for you to feel rested.

The real stat is "if you sleep less than you need to feel rested, you're at heightened risk of neurodegenerative diseases"; it's just hard to turn that into quantitative statistics.

random_ind_dude2• 4 years ago

What makes you think that the scientists didn't consider the possibility that poor sleep at night was the actual causative factor driving the progression of mild cognitive impairment (MCI) and Alzheimer's dementia?

From the paper:

Nighttime sleep disturbances are known risk factors for developing cognitive impairment or dementia. We found that the association between excessive daytime napping and incident Alzheimer's dementia remained with similar effect sizes after adjustment of covariates for nighttime sleep quantity and quality including sleep duration, sleep fragmentation, and WASO, implying a role of daytime napping independent from changes in these nighttime sleep-related characteristics. We further note that we did not observe direct associations between these nighttime sleep measures and incident Alzheimer's dementia. Therefore, it is unlikely that the increased duration and frequency of daytime napping were simply to compensate nighttime sleep loss; there might be other underlying disorders that affect, for example, the wake-promoting network that leads to lengthened sleep during both daytime and nighttime.

avazhi2• 4 years ago

I saw that paragraph and clearly it's intended as some sort of advertence to the correlation/causation thing, but the thing is - if they're coming out and saying that there's merely an association here, so what? No shit? That's like somebody coming out with a study that says that there's a correlation between being alive and dying - of course there is, but it isn't an interesting question nor is it an interesting scientific relationship (in my opinion at least).

I can remember taking a neuroscience unit in my first year of uni and spending a few weeks on how important sleep is for both acute cognitive function, and longer term maintenance that is needed to deal with all the metabolites and waste products that result from such an energetic organ like the brain. This was more than 5 years ago, and yet even then it had been demonstrated that if you take mice and subject them to sleep deprivation, they will develop neurodegenerative diseases at much higher rates, and much earlier, than controls. So what exactly is this study doing? Taking longitudinal data that shows a relationship between poor sleep and neurodegenerative diseases. 2015 called and it wants its conclusions back.

Basically I'd want to see an actual experimental study where they aren't asking participants qualitative questions about their sleep quality, quantity, etc, as if individuals in the early throes of Alzheimer's could even be expected to give accurate answers. I mean honestly: Imagine asking a person with dementia to rate the previous night's sleep amount and quality on a scale of 1-10. It's laughable.

Most longitudinal studies are lazy, and to me this paper is just publishing something to publish it (welcome to modern academic life) - I cannot see how this furthers our understanding of anything.

BeetleB• 4 years ago

If you are napping during the day, it's probable that you didn't sleep well or enough the night before.

This is a very parochial look at things. There are plenty of cultures that value an afternoon nap, and it is unrelated to lack of sleep the night before.

beebeepka• 4 years ago

Forget cultures, can't you tell from this guy's tone that he really knows what's up, while you and the authors don't?

Clearly, depriving lab creatures of sleep and observing the negative effects is enough to conclude everyone is the same and needs 8 hours of sleep. No more, no less. It's a hard number because it's science.

I guess my body telling me it's good for me that I take a nap after lunch is wrong.

TameAntelope• 4 years ago

You should email the authors of this paper about correlation and causation, I bet they'd appreciate hearing about a concept they didn't consider when writing this article.

m0llusk2• 4 years ago

It is more complex than that. Drowsiness is most often caused by a sleep debt which is commonly accumulated over a period of insufficient sleeping. Renowned sleep researcher William Dement did a big study on this which figured prominently in a modern analysis of the subject here: https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC2391074/

This study does not focus on drowsiness specifically, but rather measuring the amount of daytime sleeping and looking for increases. Under most circumstances daytime naps are short whether driven by drowsiness or the cultural standard of siestas.

racecar789• 4 years ago

Nap rooms at work are pretty common in China.

thisNeeds2BeSad• 4 years ago

So sleep apnoe causing tired people with not properly flushed brains causes alzheimers.. the conclusing is final snorring is murder..

quassy• 4 years ago

Considering apnoe and in general bad sleep is really bad for your heart, yes.

thevagrant2• 4 years ago

I wonder if ADHD has any relationship to alzheimers later in life.

I've spoken with many people with adhd who refer to adhd related fatigue as "narcolepsy lite".

user_named• 4 years ago

Everyone naps at noon in China.

m0llusk2• 4 years ago

This isn't about siesta which is common in many countries. This is about accumulating increases in the amount of time spent sleeping during the day.

Daytime napping and Alzheimer's dementia: A potential bidirectional relationship

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