The fact that we don't have that biologic pressure to have highly polyphasic sleep, I think, probably tells us something in terms of, truly, whether it's useful or not.
People dramatically underestimate how much sleep is linked to all the diseases killing us. We know a lack of sleep is linked to numerous forms of cancer - bowel, prostate, breast cancer.
Do you tend to sleep in during the weekends? That usually signals that you're trying to sleep off a debt you've accumulated during the week.
The time of night when you sleep makes a significant difference in terms of the structure and quality of your sleep.
What is dreaming, and what happens, and are there any real benefits to dreaming? Well, to take a step back, I think it's important to note that dreaming essentially is a time when we all become flagrantly psychotic.
Falling asleep is like landing a plane. It takes time. You've got to sort of gradually descend. I think one of the problems with insufficient sleep is people are not very good at predicting how poorly they are doing when they are under-slept.
That short-sleeping that we're now suffering is a consequence of our lifestyle. It's not a consequence of evolutionary habituation.
Friends say, 'Shall we go out to dinner at 8?' I say, 'I can't, I'm a 10 A.M.-till-6:30 P.M. kind of guy.' I keep that very regular, no matter what.
Stay away from screens, especially those LED screens. Those blue-light emitting devices fool your brain into thinking that it's still daytime, even though it's night-time and you want to get to sleep.
Midnight is the time when we think, 'Well, we should probably send our last email; let me just check Facebook one more time.'
We have stigmatised sleep with the label of laziness.
By keeping patients awake for longer, we build up a strong sleep pressure.
Back in the 1940s, people were sleeping on average just a little bit over eight hours a night, and now, in the modern age, we're down to around 6.7, 6.8 hours a night.
As you try to tweak your sleep one way or the other, you might be, you might be doing great - you might do better at remembering details of an event, but you might end up being poorer at abstracting the gist or the rules associated with it.
It's not that we simply get old, and memory starts to go, and sleep starts to deteriorate. But those two things actually are significantly interrelated.
Some people actually sleep better when the significant other is with them. For other couples, it's the opposite.
Individuals fail to recognise how their perennial state of sleep deficiency has come to compromise their mental aptitude and physical vitality, including the slow accumulation of ill health.
I give myself a non-negotiable eight-hour sleep opportunity every night.
Our circadian biology, and the insatiable early-morning demands of a post-industrial way of life, denies us the sleep we vitally need.
If you were not to set an alarm clock, would you sleep past it? If the answer is yes, then there is clearly more sleep that is needed.
Regularity is a key: going to bed at the same time, waking up at the same time no matter what. But I think, also, it's not just about quantity - that's what we've been discovering. It's also about quality.
Based on the science, you can make somewhat clear statements: The number of people who can survive on six hours of sleep without impairment is zero.
Human beings are the only species that deliberately deprive themselves of sleep for no apparent gain. Many people walk through their lives in an underslept state, not realizing it.
When I give lectures, people will wait behind until there is no one around and then tell me quietly, 'I seem to be one of those people who need eight or nine hours' sleep.' It's embarrassing to say it in public.
Dream sleep provides a fascinating neurochemical soothing balm. It is during dream sleep and only during dream sleep when our brain shuts off a stress-related neurochemical called noradrenalin.
If we didn't need eight hours of sleep and could survive on six, Mother Nature would have done away with 25 percent of our sleep time millions of years ago. Because when you think about it, sleep is an idiotic thing to do.
Light is a profound degrader of our sleep.
I have long been puzzled by the entrenched mentality, and often enforced practice, of longer work hours and less sleep. Innumerable policies exist within the workplace regarding smoking, substance abuse, ethical behaviour, and injury and disease prevention.
Sleep-deprived individuals also generate fewer and less accurate solutions to problems.
Sleep is Mother Nature's best effort yet to counter death.
If you look at how humans tend to want to sleep, it seems to be either, you know, sort of a monophasic way or at least a biphasic way, where there's, perhaps, a long bout during the night and then maybe a siesta-like pattern during the day.
It's during dream sleep where we start to actually take the sting out of difficult, even traumatic, emotional experiences that we've been having. And sleep almost divorces that emotional, bitter rind from the memory experiences that we've had during the day.
It's not clear whether the brain actually is designed to have nightmares or whether this is actually the process going awry.
Alcohol is a class of drugs that we call 'the sedatives.' And what you're doing is just knocking your brain out. You're not putting it into natural sleep.
You're trying to sleep off a debt that you've lumbered your brain and body with during the week, and wouldn't it be lovely if sleep worked like that? Sadly, it doesn't. Sleep is not like the bank, so you can't accumulate a debt and then try and pay it off at a later point in time.
I think many people walk through their lives in an under-slept state not realizing it. It's become this new natural baseline.
Deep non-REM sleep almost hits the save button on those recently acquired informational pieces so that when you wake up the next morning, you have remembering rather than forgetting.
You should not actually stay in bed for very long awake, because your brain is this remarkably associative device, and it quickly learns that the bed is about being awake. So you should go to another room - a room that's dim. Just read a book - no screens, no phones - and, only when you're sleepy, return to the bed.
I think the first general point to make from epidemiological studies across millions of people is the following - that short sleep predicts a shorter life. It predicts all cause mortality.
Sleep is the Swiss army knife of health. When sleep is deficient, there is sickness and disease. And when sleep is abundant, there is vitality and health.
Your subjective sense of how well you're doing under conditions of sleep deprivation is a miserable predictor of, objectively, how you actually are doing.
No one wants to give up time with their family or entertainment, so they give up sleep instead.
No aspect of our biology is left unscathed by sleep deprivation. It sinks down into every possible nook and cranny. And yet no one is doing anything about it.
It's simply that older adults don't seem to be able to generate sleep efficiently, and that's why they're not getting it.
No one would look at an infant baby asleep, and say 'What a lazy baby!' We know sleeping is non-negotiable for a baby. But that notion is quickly abandoned.
If sleep does not provide a remarkable set of benefits, then it's the biggest mistake the evolutionary process has ever made.
Creativity is, after all, lauded as the engine of business innovation.
I think we perhaps are, with sleep, where we were with smoking about 50 years ago, in that we had all of the science, and it was right there for the public discussion, but it's not yet adequately sort of percolated out into policy or even just public wisdom.
When did a doctor prescribe, not sleeping pills, but sleep itself? It needs to be prioritised, even incentivised.
Below seven hours of sleep, there are objective impairments in the body. Eight hours are recommended.
My name is Matthew Walker, I am a professor of neuroscience and psychology at the University of California, Berkeley, and I am the author of the book 'Why We Sleep.'
Many business leaders still believe that time on-task equates to productivity. Even in the industrial era of rote factory work, this was untrue. It is a misguided fallacy, and an expensive one, too. Every key facet required for business success will fail when sleep becomes short within an organisation.
The gross demonstration of caffeine is that it prevents you from falling asleep. The slightly more nefarious aspect of caffeine is that maybe you can fall asleep, but we know that the depth of deep sleep you're getting if caffeine is still in your system is severely less.
The amount of sleep - the total amount of sleep that you get - starts to decrease the older that we get. I think one of the myths out there is that we simply need less sleep as we age, and that's not true, in fact.
We now know that we imprint information during the day. We sort of - that seed is planted there within the brain during the day. In other words, we learn information. But we also know that that vision that was planted in the brain still remains in the sound of silence, in this - in the dark of night.
I just tell people I'm a dolphin trainer. It's better for everyone.
We know that efficiency and effectiveness are increased when you're getting sufficient sleep, and it will take you longer to do the same thing on an underslept brain, which means you end up having to stay awake longer. So goes the vicious cycle.
I think sleep is probably the neglected stepsister in the health conversation today. I think we've done a good job regarding physical activity and diet, but sleep has remained out there in the cold, and that's surprising to me.