Why We Sleep - Matthew Walker

[vinod1]

Thanks Liberty!

 

On a related topic, what do you think of need for sunscreen? It seems to me that humans have evolved to be in the sun, so cannot see why it would be needed. Any thoughts or research you have done on this?

 

Vinod

 

I've seen both sides of the argument.. I ended up falling on the side of using sunscreen and getting more Vit D through supplementation.

 

I think humans throughout evolutionary time mostly didn't live long enough to worry too much about skin cancers and skin aging (the sun will make your skin visibly age much faster), a lot of the problems happened after reproduction age, which is an evolutionary blind spot, and throughout most of that time most humans probably had darker skin pigmentation than I do, which also provides some natural protection. There's also issues with the ozone layer being damaged in post-industrial times (some of that has been partially corrected by banning CFCs and such, but not entirely).

 

That's my vague understanding of the situation. I still get plenty of sun without sunscreen, but if I know I'm going to be out for a long time in the sun not being covered too much, I always try to wear good sunscreen now.

 

Excellent points! That makes a lot of sense.

 

I was recently talking about evolution with a biology professor and she made the point that evolution cared (in terms of increasing your chances of survival) only if it helped in reproduction. That is why women live longer than men, because older women help their daughters care for the children, which in turn led to women having more children. So evolutionary wise there is an advantage for mothers to have their grand mother live longer. Men, apparently no so much :)

 

Thank you!

 

Vinod

 

It's not quite as simple as that, but yes, things that tend to happen after reproduction don't get encoded (or at least, not directly, which also leads to the interesting stuff in epigenetic).. That's why aging and the diseases of aging aren't programmed, but rather, a blind spot that evolution hasn't had a time to solve against because for most of humanity's existence, there were few very old people, and they didn't reproduce. There can be secondary effects, like having longer-lived adults helping the germ-line indirectly (ie. grand-parents increasing the chance of survival of their grand-kids).. I'm no expert, but I remember that at the time (10-12 years ago), I learned a lot from this series of posts:

 

https://www.lesswrong.com/s/MH2b8NfWv22dBtrs8

 

Of course reading Darwin's Origins of Species is recommended as a good starting point, but this book is also a good place to learn:

 

https://www.amazon.com/Adaptation-Natural-Selection-Christopher-Williams/dp/0691026157

 

Thanks for the links! I did read Origin of the Species 20 years back. Need to read it again as I do not remember a thing.

 

Vinod

[Liberty]

Thanks for the links! I did read Origin of the Species 20 years back. Need to read it again as I do not remember a thing.

 

Vinod

 

With great books, it's worth re-reading once in a while. It's not just about forgetting; the books stays the same, but the reader can change quite a bit, so the "software" that is in the book will get interpreted quite differently by the new "hardware" of your brain.

 

My most recent re-read of Phil Fisher had a totally different impact on me than the first time I read him years ago, for example.

 

I'm about due to re-read 'Gödel, Escher, Bach', one of my faves...

[Liberty]

New interview with Walker:

 

https://peterattiamd.com/matthewwalker4/

[Liberty]

 

A nice debunking of Alexey Guzey's 'Theses on sleep':

 

https://www.lesswrong.com/posts/sbcmACvB6DqYXYidL/counter-theses-on-sleep

[snird]

Debunking of a debunking.

Both have references, both sound right.

 

I can't wrap my head around what is correct here.

If anything it proves to me how dangerous is to rely on a single expert for topics I'm no expert in - I'll just believe the last thing I hear, given that it is presented in a smart way and with sufficient evidence (or at least what looks like evidence).

[Cigarbutt]

3 hours ago, snird said:

Debunking of a debunking.

Both have references, both sound right.

...

I can't wrap my head around what is correct here.

...

Interesting comment within an interesting debate (sleep vs else) and there are investment implications?

Just like with any decisions (ie investments (also macro topics where this is playing out now with the 'inflation' debate)), one has to extract the key ingredients (for or against an expected outcome) and come up with an informed guess:

Interestingly, many 'experts' may arbitrarily choose and put emphasis on some inputs and the 'authority' opinions, as formulated, may hide the real underlying uncertainty, potentially giving rise to unpopular contrarian opportunities.

-----

A lot of what Mr. Guzey describes is reasonable but it seems he is pulling on some arguments to a disproportionate degree. Mr. Walker's approach is very reasonable but there is a tendency to stretch conclusions to a very unusual degree, especially when dealing with the correlation/causation aspect. One of the issues when dealing with Mr. Walker's themes is that he happens to be riding a 'popular' trend and people who criticize his conclusions may look like losers and suffer from the Javert paradox.

One of the themes developed by Mr. Walker is the idea that poor sleep patterns early in life may lead to earlier cognitive decline (and Alzheimer's etc) later on, a theme plagued by the correlation-causality issue and even the possibility of reverse causality (likely people who develop early and abnormal cognitive decline may be programmed already to have poorer sleep patterns along the way).

If interested, there's this recent publication:

Subcortical Neuronal Correlates of Sleep in Neurodegenerative Diseases | Ophthalmology | JAMA Neurology | JAMA Network

It's often thought that people suffering from cognitive decline have their evolution negatively impacted by poor sleep (common sense) and an environment for good sleep should be privileged but the work suggests that the people who have cognitive decline may have an associated and pre-existing issue with neurons that are networked in a way to promote wakefulness. This study was especially interesting for me (i've been quite involved with my mother-in-law who is reaching later stages of Alzheimer's) as there is clearly a sleepiness problem in the morning (which seems to be more an inability to wake up, sort of, than as a result of a poor night's sleep).

-----

Anyways, this was mostly to underline the interesting level of humility that you shared in your post, a phenomenon which is more and more on the brink of extinction (including and especially in 'social' media discussions).

[Liberty]

The main difference between Matt and Alex is that Matt is a sleep scientist who has dedicated his life to studying the issue, he's doing practical work in the lab first hand, is talking to all the other sleep scientists and reading all the literature, his work is reviewed by others and he's highly respected by people with really good BS detectors like Peter Attia, while Alex has never spent much time in the field before spending a few days on Google Scholar cherry-picking stuff. So I think the priors on each shouldn't start from the same point.