A:Ohhh so now that it’s time to go sleep, my body is tired but my brain is not

It's 2 am and I can't fall asleep because my mind...

MH my mind is just like racing, racing racingthrough random shit

<Whisper> Hi, I’m Wendy Zukerman and you’re listening to Science Vs from Gimlet. This is the show that pits facts against forty winks. On today’s show: Sleep. We asked people to send us a little note when they were tossing and turning at night… and by the next morning… our email was full of frustrated sleepers

I have tried to go back to sleep, I've trimmed my toenails, I’ve brushed my hair,

So it’s 3AM.. It used to be 2AM, but uh I decided to look on Facebook

I’ve drafted a text, 6 texts to a dude I'd like to go on a date with, … 

KF: It's sorta kinda driving me nuts, 

I'm now watching a spider build a web on my set of shelves. it's fucking infuriarting ha

For some people, this was something that happened every now and then… for others this had become the new normal…

J I’ve been having like 4 to 5 hours of sleep at night,

BT And yeah it sucks it really sucks…After a while you start to wonder what all this interrupted sleep is doing to your brain. That’s the feeling at 5:30, 5:40 in the morning…

It really sucks when you’re tossing and turning at night… and it turns a lot of us just aren’t sleeping enough.  Around a third of Americans. According to the CDC[1][2][3].  A third! And that number of sleep deprived suckers seems to be going up[4][5][6][7]. It’s a nightmare… So do we have to take this lying down?! On today’s show we’re diving into the cutting edge research on the science of sleep to find out

  1. What happens to our brains and bodies when we don’t get enough sleep? Turns out it’s worse than we thought.
  2. What can the best science around tell us about how to get more zzzs? Does stuff like melatonin or blue light blocking glasses do anything?

When it comes to sleep there’s lots of…



…  but then there’s science…


Science Vs Sleep is coming up… after the break



Welcome back. On today’s show Sleep. We all know it feels crap when you haven’t had enough sleep… but what exactly is it doing to your body? To find out we called up Pam De Young, she helps run a sleep lab at UC San Diego[8].

PD most of the time if people ask me what i do i just tell them i work in sales

RR laugh why PD so they don't ask me questions about sleep

RR: So is this conversation your worst nightmare?


That’s Science Vs producer Rose Rimler…she’s on this sleep safari with me. So we asked Pam.

WZ how many hours a night should we be getting?

PD So most of the science shows between 7 and 9 hours

WZ: 7 to 9?

PD Yep

There are some people who seem to need less than 7 hours[9][10][11] Science calls them “wankers”... Nah science calls them natural short sleepers[12],[13],-[14]. it’s pretty uncommon, though, maybe 3%[15] of the population. But Pam says she hears this all the time.

PD they all say oh I don’t need 7 hours of sleep and you’re like, ok.  But I think the average population needs about 7 to 9. less than 7, things go wrong

This is not just something your grandmother tells you. A few years ago, a group of scientists were tasked with coming up with recommendations for the optimal amount of sleep that adults need[16]. They combed through a few hundred studies[17] that looked at people’s health and how much they slept. And they found that those who were getting 7-9 hour on the reg were the healthiest of the bunch[18]. While getting less than 7 hours was linked with some serious health conditions[19][20][21][22].

PD Diabetes rates increase, depression, immune suppression[23], weight gain, heart disease[24],

For example, one big study found that being chronically underslept raised the risk of dying from heart disease by around 20%.[25][26] Now, it can be hard to tease out the cause and effect in these studies...but we do have some clues that suggest that not enough sleep is leading to these diseases..We know that losing a few nights of sleep raises people’s blood pressure[27][28], increases inflammation[29][30] and can be a hit to the immune system.[31][32][33]


So not sleeping enough can ravage your body[34]… but what can it do to your mind?  In the long term  — studies suggest that not getting enough sleep can increase your risk of dementia…  [35][36][37][38][39] [40] 

And. In the short term… Docs have shown in the lab that missing out on sleep makes us  grumpy[41][42]… and dopey[43][44][45].

If you’re in an office you can kind of see that people that don’t sleep a lot. They tend to overshare, no filter,

Studies have found that people who don’t get a good night’s sleep report feeling more pain the next day[46][47][48][49] And one study even found that they’re less likely to find jokes funny[50]. That’s probably why you didn’t find our AMAZING seven dwarves joke funny.? Y’know with the doc and the grumpy and dopey? I guess we should be more bashful about it. Achoo! That’s sneezy.

 But seriously not getting enough sleep can really mess with our heads - Pam told us about this one study.  [51].... that measured how much slower our reaction times are when we don’t sleep enough.  And Rose and I were so intrigued by it that we wanted to try it ourselves… Here’s how it worked. First,  we had to get only 6 hours of sleep. Which actually didn’t sound all that bad but then...

Ring ring RR Ahh shut up 

Ahh ahh It’s 630, everything in my body wants me to keep on sleeping, 

Yeah... so that’s me on 6 Hours… not so chipper ehh...… but I rolled out of bed… I Met Rose at work… and a few hours later it was time to test our reaction times. To do this… there’s this computer program that scientists can use.[52] A red circle pops up on a black screen at these random times - and as soon as you see that circle… you have to hit the space bar!

WZ Your task is simple to press the space bar, when ever you see the red circle! 

RR: Ok cool!

Normally, people at their best can hit that space bar pretty quickly… but on 6 hours of sleep? 

WZ: Uh I missed the space bar!

RR: I feel like I’m doing fine, I feel like I’m focusing

WZ I’m falling asleep in front of the microphone… 

Ok so I did not think I did well on that, Rose was bit more confident. But we were only at half time. In the study, researchers wanted to compare sleepy people to those who drank alcohol. And that’s because science know that drinking makes you very slow on the draw[53][54][55]. That’s one reason you’re not supposed to operate heavy machinery...or drive a car...when you’ve had a few. And so for us that meant our next step was….

<<sound of can opening>>

WZ & RR: Cheers! For science...yeah, science

Downing 3 beers 

WZ ahh one down. Number two. RR two to go WZ let's do this [opening cans]

 In 30 minutes[56].

RR you actually have to shotgun them, it’s in the protocol



WZ it is not, that’s a lie

RR: Alright, here we go


WZ We finished number two!

RR: Wait! We finished number two.

WZ & RR Number 3eeeeee

Time to play the space bar game again

RR waiting for this red dot... there it is!  I feel like i should be faster…

WZ I got you space bar bleep you

So. Moment of truth. What made us worse -- being sober but sleepy ? Or lively but loaded? We crunched the numbers

RR Big reveal! Who won?Or is that not what this is about?

WZ: We were both worse (drumroll!)  when we were… sleepy! Yeah.. on average, we both hit the space bar on the average faster when we were drunk…

I was quite impaired…

WZ We drunk the beers fast..  

Now, in the actual study...the real science...which tested around 30 people... alcohol and sleep loss slowed everyone down pretty much equally.[57][58]. Other work have found similar stuff[59][60] .  Which was a real wake-up call.

 find very scary when I think of all the things I do on 6 hours of sleep that I would NEVER do with three beers in me

RR: Like what?

Talk to my boss…  make a science podcast … I ride my bike in traffic…

RR: I know You would never get behind the wheel after chugging three beers but you would 100 percent get behind the wheel after 6 hours of sleep. Huh.

Given all that it shouldn’t surprise you that a big review paper found that being drowsy driving ups the risk of car accidents by around 30%[61][62]. But it also ups the risk of other accidents too.[63] [64]Like, an investigative team found that the Exxon Valdez oil spill was caused, in part, because the guy steering the ship hadn’t gotten enough sleep the night before[65]. 


So we’re crap when we don’t sleep well.. But we wanted to know why? Like what is happening in our sleep deprived brains that makes us such blockheads!? Well it turns out that some recent breakthroughs in the science of sleep are starting to give us some answers. To get the goss, we spoke to Brady Riedner, assistant director of research at the Wisconsin Institute for Sleep and Consciousness[66]. 

RR And are you a good sleeper BR i'm a fantastic sleeper, yeah-01

BR i could probably fall asleep under my desk right now if you asked me to but that probably wouldn't make for good radio

So, this champion sleeper told us in the earliest days of sleep research..scientists used to think that being sleep and being awake were pretty much two very different things[67][68][69].  

BR So that’s a very binary thing, you’re either asleep or you’re awake

One of the reasons they thought this was because… scientists can use electrodes to measure the electrical signals in your brain when you’re awake and when you’re sleeping. And these signals add up to a particular pattern that looks very different in either state[70][71]. Scientists have actually converted these sleep / wake patterns into sounds. And this is what they found. Here's a real person's brain, while deeply asleep.


And when they’re awake it sounds like


Pretty cool huh.  So researchers for a long thought that while you were awake.. Every part of your brain.. Was awake. You know, making this noise.


And when you were asleep all your brain was like this.


But several years ago… scientists like Brady thought. Huh. Yknow we’re only putting a couple of electrodes on people’s heads[72][73]. . What if we used a lot more — then we could see what was happening in so much more of the brain?

BR in our lab we use 256 different locations to look at what the brain is doing RR oh wow BR we get a much better image

Armed with all these electrodes, Brady and his bunch wanted to know what kind of signals they would pick up in a really sleepy person. So they brought people into their lab...and kept them up all night, measuring their brain waves again and again and again[74]. And these people were up. They were awake, walking. Talking. Reading. So you would think.. Brady should have just been picking up the awake pattern


But he was actually picking up something else. Pockets of their brains… were asleep…


So Brady’s research suggests that when you’re really sleepy but up and about…

Your brain is awake, so you’re still doing stuff. But a part of your brain is kind of offline. It’s doing its own thing it’s kind of asleep…


Other researchers have found the same thing. And now this phenomenon is called “local sleep[75][76][77]”.  And it’s called that because it happens in local areas in your brain. So, maybe think of your brain as New York City - this research is showing that Staten Island can be falling asleep while Brooklyn parties on. 

Brady and other researchers we spoke to reckon that local sleep could help explain why we’re not at our best when we’re tired.[78].

BR You know when you might be spacing out in class and not paying attention to what the teacher is talking about, even though your eyes are open and you’re still hearing things in the classroom, it’s possible that what’s happening is that part of your brain is asleep.

RR: Well you know I feel like this kind of explains my entire life…


There are probably other things going on in your brain that explain why you become the worst of the seven dwarves when you’re sleep deprived[79]. Like there’s some evidence not getting enough sleep can affect neurotransmitters that help you stay alert[80]. But still, this idea of local sleep is just so amazing! It shows that parts of your brain will fall asleep, whether you like it or not.

And! Get this! It’s not just that you can be asleep while awake. Parts of your brain can also be awake while you’re asleep. And that could explain the strange things people sometimes do in their sleep -- things like this..

I remember thinking there were cockroaches in my bed 

This Pam De Young, the sleep researcher who you met at the beginning of the show

PD and I remember taking my bed outside…  so i had to get two doors open with keys, brought my bed outside, put it outside in the rain, so the rain was coming down, went back to my room, slept on the floor and woke up. in the morning my brother being like what are you doing? I was like there were cockroaches in my room. And he was like, no there aren’t, and you’re sleeping on the floor and it was a hard cold floor

Wait a sec and you did that while you were asleep?

PD Yes

Doing odd stuff like this in our sleep, like sleep walking... talking… or eating…are known as  “parasomnias[81][82][83][84]. And what might be happening here is that while most of the brain is sleeping -- the part capable of talking, or walking or moving furniture outside, is awake. In one study[85],, electrodes were scanning the brain of someone who was[86] sleepwalking…. it was very sweet sleepwalking, this guy hugged and kissed the air next to him. And what the electrodes recorded was that the part of his brain responsible for movement woke up during this episode...while the rest of his brain slept on[87].

BR BR yeah it’s this idea that most of your brain could be totally offline totally asleep but your the part of your brain that was responsible for executing a specific function could still be totally awake so they’re in this kind of mixed state… .

So for those of you who only got 6 hours of sleep last night -- here's what we've learned Sleep is really really important. It’s so important that when we don’t get enough it increases our risk of all these nasty diseases Plus -- getting sleep is so important for you that parts of your brain will just fall asleep whether you like it or not. So now that we know how important sleep is… How do we get more of it?  There are so many sleep hacks out there. Melatonin. Blue Light blocking glasses. Do any of them work? That’s coming up after nap time.


Welcome back. So, without sleep, we get sick, we’re slow...we make mistakes… and pockets of our brain go to sleep without us. So our next question is how do we get more sleep?  You can take a sleeping pill which might knock you out - but some of them have side effects, and they’re not recommended in the long term... So what else is there? Look online and it seems like everyone is selling some kind of trick to get us to bed.[88][89][90]

Now there’s a solution to help you fall asleep naturally introducing melatonin[91]

Wear a pair of our blue light blocking glasses and wake up feeling refreshed"

The luxurious weighted blanket helps you stay asleep[92]

Believe science[93]

You’ll sleep better dream better and live better.[94]

 So does any of this work? To find out we called up this fella.  

RF ok jolly good my name is russell foster[95] I’m a Professor of circadian neuroscience, and I am director sleep circadian science institute here at the University of Oxford-01

Russell researches our circadian rhythm -  

The circadian rhythm essentially tells you when’s a good time to be asleep and when’s a good time to be awake.

In other words, it’s our internal clock. And scientists have been trying to uncover its what makes this clock tick for a very long time. In fact one of the earliest studies looking into this… involved a scientist and his assistant who, in the 1930s, moved into a CAVE for a month.

RF This incredible cave complex in in.. uh... Kentucky[96].

And they did this because they thought the sun might be driving our internal clock and so being without sun - in a dark cave -  should mess it up[97]. So, the two scientists dragged down a set of bunk beds for their stay. 

RF one interesting thing about the bunk bed is that the feet of the bunk bed sat in, the four feet sat in four  buckets[98] and in the buckets was um -01

RF what's the stuff you shove down the lavatory[99]  

WZ poo??

RF No no, chemicals

RR bleach?

RF bleach, that’s it

RF so one the unforeseen things was that the cave was full of cockroaches didn't want to be disturbed-01

RF the cockroaches would crawl up the side of the buckets fall in die so they wouldn't crawl up the legs of the bunk bed and disturb them whilst they were asleep-01

Actually we think it was probably rats[100]  they were trying to deter - but either way - it sounds pretty terrible down there. But they were willing to do it for science .[101] and in 1938, this was big news.

well if the experiment helps us sleep better these hot nights, we vote for science.[102]

This research and later studies[103] - discovered that we do need the sun to help with our internal clock. You see without it… our clock doesn’t run at exactly 24 hours.

RF On average the human body clock is around about 24 hours and 10 to 15 minutes, under constant conditions So we drift by around about 10 to 15 minutes a day, so we would under normal circumstances get up and go to bed later and later and later each day…[104]  


So the sun is important to keeping our internal clock ticking on time …but there are lots of other moving parts in this clock as well[105]...… and they work in tandem to help make us feel asleep and wake us up[106].  And some of the most popular sleep products on the market right now are designed specifically to hack our clock…. And to help us get to sleep.

And this brings us to our first sleep hack. Melatonin. These days you can find melatonin in pills, gummies and drinks[107]. It’s huge right now. In 6 years the number of people using it in the U.S. has doubled.[108]



Ok so what is melatonin? And can it actually help you sleep better?  Melatonin is a hormone that the body makes naturally… and we pump it out when the sun goes down.[109][110] 

RF And so there’s a beautiful rise in melatonin at dusk, reaches its highest point about 4ish AM[111] in many people and declines in anticipation of waking up in the morning[112]  

RF And so because melatonin only comes out at night it is often called the dracula hormone[113]


This dracula hormone..melatonin...moves through our bloooood stream, it’s a signal to the body to say, ok,drink blood no, get sleepy! And so it actually makes sense that popping melatonin in pill could boost our natural supply, and hopefully, get us sleepier. But does it work?

Well, when scientists get people who have trouble sleeping - or who are jetlagged - to take melatonin.  And then report back on how they slept. People tend to say - yeah. I had a better night’s sleep[114][115][116][117]. But the curious thing is - that when scientists objectively measure how much more people slept, the results are kind of a letdown. Like two review papers found that people who took melatonin fell asleep just 5 minutes sooner compared with a placebo[118][119].

RF It’s having some mild effect, but I don’t think it’s a very big effect. certainly if you take it it's not gonna knock you out like uh, like a sedative

So why isn’t melatonin a miracle sleep drug[120][121]? Well it’s probably because there’s all kinds of reasons that people can’t sleep - anxiety[122], babies, netflix  -  and melatonin can’t help you with that stuff. Still though, if you’re an adult[123] and melatonin is working for you -  while we don’t have long term studies[124], as far as we can tell, it’s safe.[125][126][127][128]

RF Do we have any studies suggesting that melatonin can be toxic? I don’t know of any. I think it seems to be uh a drug that has very few side effects whatsoever[129]


Ok...so that’s a green to yellow light on melatonin. Our next stop: blue light? It’s a type of light that gets emitted from out of our favourite bed-time gadgets[130] And ragging on it is all the rage right now.  

It's all about the blue light

computers to our lights constantly bombarded with blue light

Blue light emitted from modern electronic devices increasingly interfere with our slumber"

So is this true? How bad is it to look at our screens at night? Ok so to understand how this  all might work you have to understand that we have light sensitive cells in our eyes..You might know about the rods and cones, from biology 101 but…

RF There’s a third light sensitive cell within the eye that is sending msgs to biological clock in the brain[131] [132][133] [134],

This third kind of cell gets really turned on by blue light[135][136] ….  and it sends a message to your brain [137]. That says "it’s day time!"[138]. Go get em tiger! So the idea of not looking at your blue light emitting phone…before bed… it does makes sense.

But what does the research show? Well we found a small study that had people read on an iPad for about a week[139][140].

Set on their highest intensity, four hours of consecutive use on five consecutive nights…  

While another group read a book, you know with pages. At the end of the week, the e-readers fell asleep later…but it was by ten minutes.  Ten minutes. Other studies have looked at what happens when you block this blue light - say by wearing fancy glasses blue light blocking glasses before bed - and the results have been pretty mixed. So some found no effect[141]... a few did[142].. But ultimately for all the hype here...the research is just pretty underwhelming. Which is why Russell says...

<<RF Yeah I think we need to be a bit careful about the banging on about that… >>

In Russell’s mind there’s a much more obvious reason why looking at your phone at night might be keeping you up. When you pick up your phone there's all these things on it... work emails... twitter... THE INTERNET... that just amps us up! And it seems like we just can’t help ourselves…  

Well it’s because we’re so horribly weak as a species we check our mobile phones, we check social media or check what the latest on Brexit is, and so we need to stop waking up our brains and engaging in the outside world[143][144]…  

We went down the rabbit hole on lots of different things that are supposed to help us sleep. Some things didn't have much research behind them...like, weighted blankets?[145][146] Dream on.

There was promising evidence that doing exercise[147], taking a warm bath before bed[148]...keeping your room, dark[149] and blocking out noise[150], like with earplugs.[151][152] …that stuff can help.  Waking up at the same time every morning is a good idea too[153] . If all that doesn’t really do much...there's a special kind of therapy specifically for insomnia. That can help. But the thing is… when it comes to sleep…  Russell told us that you should find out what helps you sleep better. And then do it. 

RF it's working out what works best for you and then defending it-03

Russell told us what works from him.

RF Read a few pages of a book, wind down and chill. Don’t discuss awkward, difficult things. It’s very interesting my wife always wants to discuss family finances i say no, absolutely not, no no, we’ll do it in the morning,

Pam DeYoung, who dreamt up the cockroaches…. told us her sleep routine too.

PD Oh man yeah, I have a ritual, I’m definitely in bed by ten every night if not earlier

I go into the room, I turn the fan on can’t give you an exact temperature gauge probably around 68 degrees

PD I have my curtains up, I have a sound machine 

RR: Ocean waves,

PD: yeah i don’t like the change in tone? all of the sudden that the lightning

RR: Occasionally there’s a seagull squawking

PD Yeah, I can’t handle that

RR: That would really get in the way

That’s Science Vs Sleep… good night and good luck.


WZ: Ok Rose, how many citations? RR: 158

Next week: the story of revolutionaries who fought for healthcare.  And won.

He said to me Yknow, I think you’re going to be a revolutionary little girl… WZ: Wait, who said that you? WZ: Malcolm X.

This episode was produced by Rose Rimler and Lexi Krupp with help from me, Wendy Zukerman, along with Michelle Dang, Meryl Horn and Kaitlyn Sawrey. We’re edited by Caitlin Kenney. Fact checking by Diane Kelly. Mix and sound design by Peter Leonard. Music written by Peter Leonard, Emma Munger, Bobby Lord, and Bach. Recording assistance from Dave Drexler, Tim Peterson, Zoe Sullivan, and Martin Wiggins. Sonification of EEG data came from Dr. Gerold Baier and Dr. Thomas Hermann. A huge thanks to Dr. Amandine Valomon, Prof. James Krueger, Dr. Ari Shechter, Dr. Jade Wu, Dr. Bei Bei, Dr. Connor Sheehan, Dr. Jennifer Ailshire, Dr. Agostinho Rosa, and everyone else we spoke to for this episode, especially our frustrated sleepers. Thank you so much for all the voice messages! And special thanks to Chuma Ossé, the Zukerman family and Joseph Lavelle Wilson.

I’m Wendy Zukerman, fact you next time.

[1] http://sci-hub.tw/https://doi.org/10.1093/sleep/zsy221: By 2017, almost 33.0% of respondents reported sleeping six or fewer hours

[2] 34.8% of adults reported sleeping 7 hours or less- CDC report of 2014 data: https://www.cdc.gov/mmwr/volumes/65/wr/mm6506a1.htm CDC says: We haven’t published more recent data but current estimates are likely a couple of percentage points higher, based on trends observed with other data sources and different subsets of the US population.


[3] 32.9% reported sleeping 6 hours or less in 2017 according to this study: http://sci-hub.tw/https://doi.org/10.1093/sleep/zsy221

[4] A 2019 study looking at NHIS data again from working adults found that over nine years, 33.6% of working adults were sleeping 6 hours or less. Just looking at the 2018 data, that number jumps to 35.6%. http://sci-hub.tw/10.1007/s10900-019-00731-9

[5] Study published this year looked at survey data from 2004-2017. 28% of respondents reported less than 6 hours of sleep in 2004, while 33% reported that in 2017.

[6] Avg sleep was 7.4 hours in 1985 and 7.18 hours in 2012. The age-adjusted percentages of sleeping ≤ 6 h were 22.3% in 1985, 28.6% in 2004, and 29.2% in 2012

[7] The teens are sleeping less since the early ‘90s, but this study doesn’t look past 2012. Self reported data from 1991-2012 (N= 272 077, across 130 schools over 20 yrs). https://pediatrics.aappublications.org/content/135/3/460…..Sleep decreased across time with the largest decrease 

[8] https://medschool.ucsd.edu/som/medicine/research/centers/sleep-research/people/Pages/default.aspx

[9] Sleep duration varies greatly (and appear to be normally distributed in the general population) among individuals and are heavily influenced by both genetic and environmental factors (10–15) Mutation associated with Familial Natural Short Sleep examined in mice in this study, but: “Mice carrying the mutation showed a similar phenotype to human FNSS. These data support a causal role of the NPSR1-Y206H mutation for the human short sleep pheno- type. Thus, the NPS/NPSR1 pathway provides a potential ther- apeutic target to improve human sleep and treat sleep-related disorders.”

[10] https://academic.oup.com/jcem/article/88/1/26/2845992

[11] http://sleepeducation.org/sleep-disorders-by-category/insomnias/short-sleeper 

[12] https://www.ncbi.nlm.nih.gov/pubmed/28325617 

[13] https://stm.sciencemag.org/content/11/514/eaax2014 


[15] http://sleepeducation.org/news/2009/08/14/the-short-sleep-gene-when-six-hours-is-enough describing this study: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2884988/ but the 3% estimation is in the press release, not the paper; more recent estimates are in the same ballpark: “a low, single-digit number: https://medicalxpress.com/news/2019-03-short-sleepers-hours-night-fine.html

[16] The AASM and SRS charged the panel with developing a recommendation for sleep duration in adults. This charge coincides with the goals of the National Healthy Sleep Awareness Project

[17] The final list included 311 publications for consideration by the panel

[18] In general, there was consensus that 6 hours of sleep or less was inappropriate to support optimal health in adults. There was also consensus that 7–9 hours of sleep were appropriate to support optimal health in adults. There was consensus that the appropriateness of 9 or more hours of sleep on optimal adult health could not be ascertained with certainty.

[19] 2017 study that provides an overview of health effects: “Compared with normal sleep, short sleep showed a statistically significant increase in mortality due to all causes at a RR of 1.12 (95%

CI 1.08e1.16, P <0.005, I2 ¼ 25%, N of datasets ¼ 36; Figs 2 and 3). Qualitatively similar significant results were obtained for diabetes mellitus, hypertension, cardiovascular disease, coronary heart disease, and obesity, at RR of 1.37, 1.17, 1.16, 1.26, and 1.38, respectively (Fig. 2).  http://sci-hub.tw/10.1016/j.sleep.2016.08.006

[20] In the pooled analysis, short duration of sleep was associated with a greater risk of death (RR: 1.12) https://academic.oup.com/sleep/article/33/5/585/2454478

[21]Large review of 24 studies  showing short sleep increased risk of high blood pressure:  https://www.sciencedirect.com/science/article/abs/pii/S1389945712004443

[22] Numerous, large cross-sectional and longitudinal population-based observational studies provide largely concordant findings linking short sleep duration to obesity, cardiovascular disease, diabetes, and depression.

[23] study shows bad sleep makes you more susceptible to catching a cold-- https://www.ncbi.nlm.nih.gov/pubmed/26118561 

[24] “During 10-15 years of follow-up, 1,486 CVD and 1,148 coronary heart disease (CHD) events occurred. Short sleepers (≤ 6 h) had a 15% higher risk of total CVD (HR: 1.15; 95%CI: 1.00-1.32) and a 23% higher risk of CHD (HR: 1.23 [1.04-1.45]) compared to normal sleepers (7 h) after adjustment for all confounders.”  https://academic.oup.com/sleep/article/34/11/1487/2454617

[25] 2017 study examining research from 1966-2017: “In total, our meta-analysis included 19 studies (31 cohorts) with a total of 816,995 individuals with 42,870 cardiovascular disease mortality cases. In pooled analyses, both short (risk ratio 1.19; 95% CI 1.13 to 1.26, P<0.001, I2=30.7, P heterogeneity=0.034), and long (risk ratio 1.37; 95% CI 1.23 to 1.52, P<0.001, I2=79.75, P heterogeneity<0.001) sleep durations were associated with a greater risk of cardiovascular disease mortality.” http://sci-hub.tw/10.1177/2048872617741733 

[26] Older analysis from 2011 found short sleepers were 48% more likely to develop or die from coronary heart disease (but found no effect for all pooled cardiovascular disease): https://academic.oup.com/eurheartj/article/32/12/1484/502022

[27] These data suggest that lack of sleep may increase sympathetic nervous system activity on the following day, leading to increased blood pressure. - https://www.ncbi.nlm.nih.gov/pubmed/8641742 

[28] Several studies have found that experimental sleep deprivation leads to increased blood pressure (BP),11-14 and even half a night of sleep loss has been reported to increase BP in subjects with hypertension or prehypertension.15  …. some studies show an increase in stress hormones after a single night of bad sleep, others find no significant effect. http://sci-hub.tw/https://www.sciencedirect.com/science/article/abs/pii/S0033062008000911 

[29] https://www.ncbi.nlm.nih.gov/pubmed/14975482 “ We propose that sleep loss may be one of the ways that inflammatory processes are activated “

[30] According to experimental studies, this adverse effect includes the predominance of sympathetic activity and an increase in proinflammatory cytokine levels.” - http://sci-hub.tw/10.1056/NEJMc0807104

[31] https://jamanetwork.com/journals/jama/article-abstract/1032061 Healthy people sleep deprived for 6 days (four hours a night) and then given the flu shot had half the antibodies compared with well-rested control group

[32] 1 night of sleep loss increases urinary excretion of norepinephrine https://www.ncbi.nlm.nih.gov/pubmed/8641742 

[33] During experimental sleep deprivation of healthy participants, white blood cells and other markers of inflammation show increases in the range of those associated with the future development of cardiovascular disease. http://sci-hub.tw/https://www.sciencedirect.com/science/article/abs/pii/S0033062008000911

[34] Short sleep duration is associated with an increased risk of developing features of the metabolic syndrome in adults. https://www.ncbi.nlm.nih.gov/pubmed/24099879

[35]https://j2vjt3dnbra3ps7ll1clb4q2-wpengine.netdna-ssl.com/wp-content/uploads/2018/06/sleep-Alzheimers-health-advisory.pdf “Significant evidence suggests that insufficient sleep or poor sleep may in fact contribute to the development of Alzheimer’s disease.”

[36] “Relative to participants sleeping 8 to 9 hours/night, the RR of dementia or MCI associated with sleeping <7 hours in the demographic-adjusted model (model 1) was 1.28 (0.98, 1.66)” http://sci-hub.tw/10.1016/j.jalz.2017.06.2269

[37] the substantial body of data supporting a link between sleep and cognition suggests that improving sleep quality could improve cognitive performance

[38] https://www.sciencedirect.com/science/article/abs/pii/S1087079217300114

[39] https://www.thelancet.com/journals/laneur/article/PIIS1474-4422(14)70172-3/fulltext “We present evidence from observational studies of the risk of cognitive decline and dementia associated with sleep disturbances in older adults”

[40] https://science.sciencemag.org/content/366/6465/628 

[41] https://www.sciencedirect.com/science/article/abs/pii/0022395661900036 


[43] Sleep deprivation increases sensitivity to stress, pain, and increases emotional distress and mood disorders, as well as worse cognition, memory performance.

[44] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3964364/

[45] https://www.sciencedirect.com/science/article/abs/pii/S0167876013001475 

[46] https://www.tandfonline.com/doi/abs/10.1080/08990220.2017.1317241 

[47] A range of evidence suggests that people tend to report greater pain after having a night of poor sleep. ….Existing evidence in the epidemiologic, clinical, infrahuman, and human experiment studies tends to support the notion that disordered sleep adversely affects pain sensitivity and analgesic responses. http://sci-hub.tw/https://link.springer.com/article/10.1007/s11926-011-0204-8 

[48] Optimism-sociability progressively declined over consecutive days of sleep restriction by 15%. Bodily discomfort showed a slight, but significant interindividual increase of 3% across days of sleep restriction due to significant increases of generalized body pain, back pain, and stomach pain. (Compared effects of 8-hour vs 4-hour sleep)

[49] According to the majority of the studies, sleep deprivation produces hyperalgesic changes. Furthermore, sleep deprivation can interfere with analgesic treatments involving opioidergic and serotoninergic mechanisms of action. http://accurateclinic.com/wp-content/uploads/2016/10/Sleep-deprivation-and-pain-perception-2006.pdf 

[50] “Following 49.5 hours of continuous wakefulness, the means for both verbal and visual humor within the placebo group were es- sentially 1 standard deviation below the average performance of healthy, normal, non–sleep-deprived individuals, suggesting that sleep loss adversely affects the capacity to appreciate humor.” https://academic.oup.com/sleep/article/29/6/841/2708241

[51] https://pdfs.semanticscholar.org/55ad/de50f4138f4b8e8835aba4e8742b94ea0e5f.pdf

[52] http://pebl.sourceforge.net/ we ran the /ppvt

[53] https://www.ncbi.nlm.nih.gov/pubmed/23868552

[54] Tests using both fast and slow frequency stimuli showed that alcohol slowed premotor RT https://www.ncbi.nlm.nih.gov/pubmed/17286346

[55] “The occurrence of alcohol-induced protracted cognitive errors long after speed returned to normal is identified as a potential threat to the safety of social drinkers” https://www.ncbi.nlm.nih.gov/pubmed/18540784

[56] , in the morning, consumed 0.0 g/kg, 0.3 g/kg, 0.6 g/kg, or 0.9 g/kg ethanol from 8:30 AM to 9:00 AM

[57] Looking at the 0.6 g/kg result for 10% fastest rxn time showed score drop of -6.13; where sleep loss of 2 hours on that measure is -5.95. Table 3 says 0.5 g/kg is equivalent to 2-3 beers.

[58] Using 10% fastest rxn time because: “sleep loss and ethanol did not differ in effects on lapses. Thus relative potency analyses were not conducted on this parameter. Ethanol slowed the 10% fastest reaction times (F = 3.40, P < .02), with the 0.0-g/kg and 0.3-g/kg doses differing from the 0.9-g/kg dose. Sleep loss also slowed the 10% fastest reaction times (F = 4.11, P < .01)” and in Table 2, 10% fastest rxn time went down -17.9 from baseline when ppl had highest dose of alcohol (0.9 g/kg); it went down 18.1 for people who had zero sleep. So, sleep loss is WORSE than drunkenness on this measure. Table 3 says 1.0 g/kg is equivalent to 5-6 beers.

[59] https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1530-0277.1993.tb00839.x

[60] One group of studies examined the comparative importance of sleep deprivation effects on performance against an established benchmark of alcohol consumption. In the laboratory (Dawson and Reid, 1997; Lamond and Dawson, 1999; Williamson and Feyer, 2000; Falleti et al., 2003; Roehrs et al., 2003), in a driving simulator (Fairclough and Graham, 1999; Arnedt et al., 2001), and on a closed track (Powell et al., 2001), performance while sleep deprived was at least as poor as performance while at the legal limit for alcohol consumption for driving (either 0.05% or 0.08% blood alcohol concentration).

[61] Federal data suggests that approximately 15–33% of fatal crashes in the United States of America may be due to drowsy driving (Maaia, Grandner, Findley, & Gurubhagavatula, 2013); Based on our systematic review and meta-analysis, drowsy driving increase road crashes by 1.29 to 1.34 times higher than driving without sleepiness,

[62] https://oem.bmj.com/content/60/9/689: Driver sleepiness causes about 10% of all UK road crashes, with a higher rate for monotonous motorways and similar trunk roads.1,2 Such crashes are more likely to result in death or serious injury2 owing to a failure to brake beforehand and a higher impact speed. 

[63] https://jamanetwork.com/journals/jamapsychiatry/article-abstract/1370486

[64] https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-2869.1995.tb00220.x

[65] Exxon Valdex accident was caused in part because the guy steering the ship was up all night: https://web.archive.org/web/20100611194527/http://www.ntsb.gov/Recs/letters/1990/M90_26_31A.pdf “The Safety Board concludes that the third mate could have had as little as 4 hours sleep before beginning the workday on March 23 and only a 1- to 2-hour nap in the afternoon. Thus, at the time of the grounding, he could have had as little as 5 or 6 hours of sleep in the previous 24 hours. Regardless, he had had a physically demanding and stressful day, and he was working beyond his normal watch period. “

[66] https://sleep-and-consciousness.wisc.edu/staff/riedner-brady/ 

[67] Sleep is typically considered a global phenomenon that affects the whole brain uniformly and simultaneously. Along the same lines, sleep and wakefulness are usually treated as two mutually exclusive behavioral states, with hardly any grey zone in between. This ‘all-or-none view’ of sleep has dominated sleep research for a long time

[68]  Earlier theories of sleep presumed that it occurred at the level of the whole organism and that it was governed by central control mechanisms. However, evidence now indicates that sleep might be regulated at a more local level in the brain: it seems to be a fundamental property of neuronal networks and is dependent on prior activity in each network.  http://sci-hub.tw/https://www.nature.com/articles/nrn2521 

[69] Review starting pg. 910 http://sci-hub.tw/https://www.nature.com/articles/nrn2521 



[72] Early EEG studies used 2-6 electrodes https://www.physiology.org/doi/abs/10.1152/jappl.1959.14.3.397

[73] 6-channel study from 1997 http://sci-hub.tw/https://doi.org/10.1016/s0013-4694(97)00070-9

[74] “hd-EEG recordings (256 electrodes, Electrical Geodesics Inc)” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3524543/ 

[75] The historic sleep regulatory paradigm invokes "top-down" imposition of sleep on the brain by sleep regulatory circuits. https://www.ncbi.nlm.nih.gov/pubmed/30502497 

[76] http://sci-hub.tw/https://www.sciencedirect.com/science/article/abs/pii/S0959438816302410 

[77] In an awake state, neurons in the cerebral cortex fire irregularly and electroencephalogram (EEG) recordings display low-amplitude, high-frequency fluctuations. During sleep, neurons oscillate between ‘on’ periods, when they fire as in an awake brain, and ‘off’ periods, when they stop firing altogether and the EEG displays high-amplitude slow waves.

[78] https://www.jneurosci.org/content/35/11/4487 

[79] Some hypotheses are proposed to explain why cognitive performance is vulnerable to prolonged wakefulness. The theories can be divided roughly in two main approaches, in which SD is assumed to have (1) general effects on alertness and attention, or (2) selective effects on certain brain structures and functions. In addition, individual differences in the effects have been reported.

[80] On a microscopic level, sleep deprivation is associated with increased levels of adenosine, a neuromodulator that has a general inhibitory effect on neural activity. The inhibition of cholinergic nuclei appears particularly relevant, as the associated decrease in cortical acetylcholine seems to cause effects of sleep deprivation on macroscopic brain activity http://sci-hub.tw/10.1007/s00018-007-6457-8

[81] https://www.ncbi.nlm.nih.gov/pubmed/16251953

[82] http://sci-hub.tw/https://doi.org/10.1097/01.nrl.0000149970.67188.d6 

[83] https://bestpractice.bmj.com/topics/en-us/1177 

[84] https://www.ncbi.nlm.nih.gov/pubmed/16251953:”Sleepwalking is prevalent in childhood (1–17%), peaking at 11–12 years of age, and is far more common in adults (nearly 4%) than generally acknowledged”; “As with sleepwalking, sleep terrors are much more prevalent in adults than generally acknowledged (up to 3%)”

[85] Also seen something similar here: https://www.sciencedirect.com/science/article/pii/S0140673600025617 

[86]  Fourteen stereotactically implanted intracerebral multilead electrodes were placed in the primary sensory-motor cortex (central and postcentral gyrus), supplementary sensory motor area, superior and inferior parietal lobules, pre-central and central cingulate gyrus, middle and inferior frontal gyrus, and F1-F2 sulcus (Figure1).  

[87] Video-S-EEG captured an episode, occurring during slow wave sleep, in which the patient turned in bed with his eyes closed, extended his arms as if to embrace someone, gave a kiss, and uttered a few unintelligible words. When called by the technician, he did not answer but lay down, and continued to sleep in stage 2 NREM sleep. The episode lasted 32 seconds; the patient had no recall of the event the following morning. …...In the motor and central cingulate cortices, after a short initial increase in delta activity, the presence of sustained fast activity with a frequency of approximately 25 Hertz was detectable (the same fast activity seen in wakefulness during movements, Figure 1 lower right corner); this fast activity was then interrupted by bursts of delta waves, before receding into the background NREM sleep activity (Figure 1)....wakefulness and NREM sleep.2 In this patient, we showed that brain activity can exhibit different local behaviors during arousal parasomnias. The simultaneous presence of different states of being (i.e., wakefulness and NREM sleep) was evidenced as local brain phenomena

[88] https://www.cnn.com/2015/05/14/health/sleep-hacks/index.html

[89] https://www.sleepcycle.com/how-to-fall-asleep/serious-sleep-hacks-that-really-work/ 

[90] https://www.doctoroz.com/gallery/5-easy-steps-better-nights-sleep

[91] https://www.youtube.com/watch?v=Mi5FReyGqG8

[92] https://www.youtube.com/watch?v=_O0RilUHWkM

[93] https://www.youtube.com/watch?v=8r1F5lJgtOs

[94] https://www.ispot.tv/ad/AFU3/casper-sleep-better

[95] https://www.ndcn.ox.ac.uk/team/russell-foster

[96] https://www.nps.gov/maca/index.htm

[97] See page 178 in  https://www.amazon.com/Wakefulness-Midway-Reprint-Nathaniel-Kleitman/dp/0226440737; (searchable at https://books.google.com/books?id=FwKzKM4sdEoC&dq)

[98] https://www.lib.uchicago.edu/collex/exhibits/discovering-beauty/mammoth-cave/

[99]See photo on page 233 in https://books.google.com/books?id=bKdZZOkEil8C&pg=PA233&lpg=PA233

[100] His choice of the constant environmental conditions of Mammoth cave for his circadian rhythm studies necessitated his devising and incorporating traps to prevent rats from climbing into bed with the sleepers.

[101]  in this, the two subjects (so cavemen, natch) kept to a strict 28 hour per day schedule throughout the month, so there was no drift in the times they went to bed. What they found was that body temperature rhythms resisted change -- even though they had imposed a '6-day' week in the cave, with 6 sleep-wake cycles, they still had '7-day' temperature cycles. In other words, cells have an innate rhythm that doesn't require environmental info. Source: https://www.amazon.com/Wakefulness-Midway-Reprint-Nathaniel-Kleitman/dp/0226440737/ 

[102] https://www.youtube.com/watch?v=xMH9eF5Bq70 

[103] Here, they found that the human circadian cycle is about 25 hours long -- hence going to bed a little later each night. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1330995/?page=1

[104] the intrinsic period of the human circadian pacemaker averages 24.18 hours http://ibo2013.org/webcontent/downloads/references/EES_DailyRhythm_Reference_Charles1999.pdf 

[105]https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3621793/; https://www.researchgate.net/profile/Thomas_Jhou/publication/11636372_The_sleep_switch_Hypothalamic_control_of_sleep_and_wakefulness/links/5b058932aca2725783d886c9/The-sleep-switch-Hypothalamic-control-of-sleep-and-wakefulness.pdf https://www.medscape.com/viewarticle/472385_8

[106] See page 178 in  https://www.amazon.com/Wakefulness-Midway-Reprint-Nathaniel-Kleitman/dp/0226440737; (searchable at https://books.google.com/books?id=FwKzKM4sdEoC&dq)

[107] https://usa.drinkdreamwater.com/pages/how-it-works

[108]  the use of melatonin in the US more than doubled over the 6 years spanning 2007-2012, which is from the latest data available from the US Department of Health and Human Services.

[109] A neural output signal, generated by the SCN, induces the synthesis of melatonin at night by the pineal gland. The hormone is released into the third ventricle and subsequently the circulation (Reiter, 1991).


[111] See Fig 1 http://sci-hub.tw/https://www.sciencedirect.com/science/article/abs/pii/S0024320503008142 



[114] Melatonin demonstrated a significant effect in improving sleep quality. Subjects randomly assigned to melatonin had improvements in sleep quality compared to placebo (standardized mean difference (SMD) = 0.22 [95% CI: 0.12 to 0.32], Z = 4.52, p<0.001).

[115] https://link.springer.com/article/10.1186/1475-2891-13-106 “Based on the high quality and favorable results reported, the SMEs concluded that in a jet lagged population, further research may have an impact on the confidence in the estimate of the effect, and as such, provide a weak recommendation in favor of melatonin use for rebalancing the sleep-wake cycle in people with jet lag.”

[116]https://www.cochrane.org/CD001520/DEPRESSN_melatonin-for-the-prevention-and-treatment-of-jet-lag “Melatonin is remarkably effective in preventing or reducing jet lag, and occasional short-term use appears to be safe.

[117] https://www.sciencedirect.com/science/article/pii/S0091302218300141 

[118] Quantitative analysis of the five eligible RCTs [44,46e49] showed an overall significant reduction in the time to fall asleep between the effect on sleep onset latency for melatonin in patients with primary insomnia compared with placebo (total mean difference ¼ 5.05 min, 95% CI: 8.51, 1.59). T

[119] Melatonin significantly reduced sleep latency on both objective (WMD = 5.50 minutes [95% CI = 2.29 to 8.71], Z = 3.36, p<0.001) and subjective measures (WMD = 10.68 minutes [95% CI: 5.78 to 15.58], z = 4.27, p<0.001).

[120] Weak recommendations were made for preventing phase shifts from jet lag, for improving insomnia in both healthy volunteers and individuals with a history of insomnia, and for initiating sleep and/or improving sleep efficacy. Based on the literature to date, no recommendations for use in shift workers or to improve hormonal phase shift changes in healthy people can be made at this time.

[121] Said evidence in favor of melatonin very weak http://sci-hub.tw/https://doi.org/10.5664/jcsm.6470

[122] https://www.mayoclinic.org/diseases-conditions/insomnia/symptoms-causes/syc-20355167 

[123]  “Potential safety issues in the use of the hormone melatonin in paediatrics” “The National Institutes of Health (NIH) states that ‘Melatonin should not be used in most children. It is possibly unsafe. Because of its effects on other hormones, melatonin might interfere with development during adolescence.””

[124] http://sci-hub.tw/10.1111/jpc.12840 “ There have been no appropriate studies to show that melatonin is safe in the long term for children or adults”

[125] http://sci-hub.tw/10.1007/s40261-015-0368-5 

[126] AEs of exogenous MLT and MLT analogues were reported in 11 (5.6%) of the included reviews. .. “Given the overwhelming benefits of MLT treatment and the existence of very few and mild AEs (also for long-term use), the risk–benefit ratio favours MLT.” https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-017-1000-8 

[127] Of the total 35 studies included in our analysis, 15 included information on adverse events. No serious adverse events were reported. https://link.springer.com/article/10.1186/1475-2891-13-106 

[128] Even though our patient population was diverse, there was no evidence of side effects that were specific to CR-melatonin.  

[129]“The acute toxicity of melatonin as seen in both animal and human studies is extremely low. Melatonin may cause minor adverse effects, such as headache, insomnia, rash, upset stomach, and nightmares. In animals, an LD50 (lethal dose for 50% of the subjects) could not be established. Even 800 mg/kg bodyweight (high dose) was not lethal.” https://www.medscape.com/viewarticle/472385_8; https://toxnet.nlm.nih.gov/cgi-bin/sis/search/a?dbs+hsdb:@term+@DOCNO+7509

[130]“Newer computers and TV screens are now frequently equipped with light-emitting diodes (LED), which peak in the short-wavelength region (i.e., the blue range at ∼460 nm).” https://www.ncbi.nlm.nih.gov/pubmed/21415172

[131] https://onlinelibrary.wiley.com/doi/full/10.1002/cne.24176

[132] https://www.jneurosci.org/content/jneuro/20/2/600.full.pdf


[134]“Light coming through the closed eyelids also can affect physiological responses at the time that the EOPs presumably are functional (429).  https://www.physiology.org/doi/pdf/10.1152/physrev.1979.59.3.449

[135] Researchers bred mice without rods or cones and found the mice STILL had a circadian rhythm that responded to light  -they suspected it was a certain kind of cell, so next they ablated those cells in these mice. they found that this messed up their circadian rhythms. - they found two blind people whose eyes did not have rods and cones. their circadian rhythm still responded to light, and it responded most to blue light.



[138] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3619500/

[139] https://www.pnas.org/content/112/4/1232#sec-7

[140] http://sci-hub.tw/10.1073/pnas.1418490112 

[141] We find a lack of high quality evidence to support using BB spectacle lenses;  study involving normal participants found no observed difference in sleep quality." https://www.ncbi.nlm.nih.gov/pubmed/29044670" 

[142] Based on actigraphy, TST was significantly increased in the amber vs. clear lenses 234 condition (358.80 ± 66.29 vs. 330.33 ± 66.01 min; p=0.035; d=0.65)

[143] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4857587/  finds correlation between amount of social media use and poor sleep, but doesn't tease out whether the cause is social interaction activity or physiological effects of light exposure.

[144] Sept 2019 review on sleep and social media use explicitly says that while the correlation between high social media use and poor sleep has been found in a number of studies, there's still no certainly what the driving mechanism is (https://link.springer.com/article/10.1007/s40675-019-00146-x)

[145] http://www.diva-portal.org/smash/get/diva2:1081315/FULLTEXT01.pdf study showing positive effects done by weighted blanket company

[146]  mostly about kids with autism - but the best controlled study we can find for that population shows the blankets had no effect on increasing sleep time. https://pediatrics.aappublications.org/content/134/2/298.short

[147] A 2017 review paper found that most studies (29/34) showed any exercise or physical activity improved sleep quality/ duration-- it didn’t matter how people exercised. Most pronounced effects in middle-aged and elderly people.

[148] “… was associated with both improved self-rated sleep quality and SE, and when scheduled 1–2 h before bedtime for little as 10 min significant shortening of SOL.” https://www.sciencedirect.com/science/article/abs/pii/S1087079218301552?via%3Dihub

[149] https://www.sciencedirect.com/science/article/abs/pii/S0360132318300325 “Complete darkness is optimal for sleep”

[150] https://www.ncbi.nlm.nih.gov/pubmed/27762252

[151] And helped infants sleep better in a small study - https://www.ncbi.nlm.nih.gov/pubmed/2405784 

[152] White noise DID help patients fall asleep more quickly and sleep better in the ICU in a number of studies - http://sci-hub.tw/10.1016/j.sleep.2004.12.004; All the studies on white noise produced positive changes in at least some of the participants with three being rated as positive and two mixed because not all participants responded. Three of the studies were preponderant. This makes white noise a promising intervention worthy of further study. http://sci-hub.tw/10.1016/j.smrv.2017.07.004

[153] Current clinical sleep medicine therapies (i.e., stimulus control, CBT-I) call for regularity in wake time but permit variability in bedtime as individuals are instructed not to go to bed until they are sleepy [101]. These treatments are effective at improving sleep in clinical populations, but the isolated benefit of the sleep timing component is not known, and the extent to which a sleep timing recommendation is effective in the absence of a clinician's guidance is unclear" http://sci-hub.tw/10.1016/j.smrv.2014.10.001