April 1, 2019


#47 – Matthew Walker, Ph.D., on sleep – Part I of III: Dangers of poor sleep, Alzheimer’s risk, mental health, memory consolidation, and more

"I think that sleep may be one of the most significant lifestyle factors that determines your risk ratio for Alzheimer's disease." — Matthew Walker

Read Time 18 minutes

In part 1 of this 3 part series, Matthew Walker, professor of neuroscience at UC Berkeley and expert on sleep, describes the different stages, and cycles, of sleep, including what he calls the 4 pillars of sleep, and how they contribute to memory consolidation and numerous important pathways to mental health. We also get into the dangers of chronic sleep deprivation, such as the development of dementia, and the more acute dangers of sleep deprivation like fatal car crashes which are most often caused by drowsy driving. We also discuss the different and important roles of REM vs. non-REM sleep, and the impact that bad sleep habits can have specifically on those sleep stages.


We discuss:

  • Matthew’s background and interest in sleep [5:00];
  • Sleep and Alzheimer’s disease, and the 4 pillars of sleep [11:15];
  • Stages of sleep, sleep cycles, and brainwaves [40:15];
  • Memory and sleep, and the risk of insufficient REM sleep [54:45];
  • Evolutionary reasons to sleep [1:01:00];
  • The early riser vs. the night owl, and tips for overcoming jet lag [1:09:15];
  • Is there one type or stage of sleep that is most important? [1:16:30];
  • The dangers of drowsy driving [1:25:45];
  • The timeliness of Matthew’s book, and how the conversation of sleep has changed over the past several years [1:34:15]; and
  • More.

Matthew’s background and interest in sleep [5:00]

  • Started med school in UK at age 18 but professor told him he was a scientist, not doctor (focused on questions, not answers)
  • Instead, he got undergrad in neuroscience at University of Nottingham
  • Then got Ph.D. at Newcastle University and his research was funded by the Medical Research Council in London
  • Went to Harvard for faculty position in psychiatry, there for 7 years – did not like winter or combative/competitive environment at Harvard
  • Came to Berkeley, has been there since

How did he develop his passion for sleep science?

  • Always interested in states of consciousness, anesthesia, hypnotism, brain switching between mental states
  • Sleep is a key example: state that happens to almost every living creature every 24 hours
  • Sleep accounts for ~1/3 of our lives – we understand eating, drinking, and mating, but not sleep
  • “We sleep to cure sleepiness” is not an answer, we can’t seem to unravel the mystery
  • Brilliant minds haven’t yet cracked it, so Matthew thought the topic would sustain a whole career

“So it was, for me, this perfect collision of a fascination in an innate biological problem, and universal behavior conserved across evolution, together with the fact that we did it for a third of our lives. Plus the fact that science had not been able to crack this nut, it was one of the last great remaining scientific mysteries.”

Sleep and Alzheimer’s disease, and the 4 pillars of sleep [11:15]

  • Walker was studying the brainwave patterns in people with dementia but not getting anywhere
  • Noticed that different pathologies hit sleep centers, others spared until late in process
  • Needed to measure patients while sleeping, not aware: then results took off

Could sleep disruption be a biomarker of dementia, or even an underlying cause? … [end of show notes preview]

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Matthew Walker Ph.D.

Dr. Walker earned his degree in neuroscience from Nottingham University, UK, and his PhD in neurophysiology from the Medical Research Council, London, UK. He subsequently became a Professor of Psychiatry at Harvard Medical School, USA. Currently, he is Professor of Neuroscience and Psychology at the University of California, Berkeley, USA. He is also the founder and director of the Center for Human Sleep Science.

Dr. Walker’s research examines the impact of sleep on human health and disease. He has received numerous funding awards from the National Science Foundation and the National Institutes of Health, and is a Kavli Fellow of the National Academy of Sciences.

Dr. Walker is the author of the International Bestseller, Why We Sleep. It has a singular goal: to reunite humanity with sleep.

In addition, Dr. Walker is an internationally recognized speaker, a successful entrepreneur, and a Sleep Scientist for Google.


Twitter: @sleepdiplomat


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  1. For the AMA I am an IM doc and still do clinic and hospital and am on call 24/5 and 1/4 weekends , sometimes I can do 7-14 days with multiple calls past midnight from the hospital. Besides not taking call anymore are their any suggestions recommendations that could help me deal with my fragmented sleep and lessen the deleterious effects it is having on me?

  2. I wonder how much sleep are patients in hospitals getting. Both in terms of length and in terms of quality (lights, noise, other interruptions). How does that affect their health?

  3. I am leaving this comment regarding induced anxiety resulting from knowing that one will not get good sleep.

    I recently listened to all three podcasts with Mathew Walker. This was a great source of knowledge for me and at times, I found the podcasts quite frightening.

    My accumulated knowledge on how to get a good night of sleep is now making me anxious. I worry that this anxiety deprives me of sufficient sleep and thus can limit my academic and sporting performance. For example, if I have had 3 consecutive nights of poor sleep prior to a half-marathon, I tend to believe that my performance will be subconsciously limited, over which I will have no control.

    I wonder if I would be better off not knowing too much information about sleep rather than having sleepless nights over it, knowing that I won’t get a good night’s sleep. I would appreciate hearing your opinion on this matter.

  4. Hello Adam Witt- why wouldn’t you want to know more about it, if you have the ability to change it. if you can change it, why wouldn’t want to measure it.
    In this way, you can improve your performance or general quality of life.

  5. Peter, I think this is one of your best podcasts. It is hard to imagine one could listen to over six hours of talk on sleep and not fall asleep at some point, but truthfully, it has been a joy. Matthew Walker is incredibly lucid and his clarity of thought is remarkable indeed. I love it when a person speaks without rushing into it and you can almost visualize his thoughts as he verbalizes them. I bought six copies of his book and gave them to my near and dear, liked it so much.

    It is absolutely true that we neglect our sleep, at our own peril. Nobody said it better than The Bard all those centuries ago.

  6. This is very frustrating, everyone tells you how bad is the lack of sleep but there is no clear healness for insomnia. It´s like everyone telling how important is breastfreeding when there is no milk or how bad a C-section is for the baby´s microbiota when there is no other choice.

  7. This is extremely comprehensive. Thank you! Unfortunately, as a couple people have commented, I’m terrified of what is going to happen to me, as sleep has become my biggest problem ever since I hit perimenopause, despite taking oral progesterone. I having been losing this battle ever since it started over a year ago. Is there anyone studying this right now? Doing clinical studies as to exactly what is REALLY going on–what neurotransmitters, hormones (or other factors) are related? What medications (if any) work best? What helps more: estrogen? progesterone? both? WHY can’t we sleep? The lack of it has become my biggest living nightmare. Learning about the effects of sleep deprivation only cause more frustration as I am at a loss to control this. If I were granted only one wish right now, it would be the ability to sleep as I used to and wake up actually feeling refreshed. Perhaps it’s simply too complicated to study.

    • OMG, what Tempa Hull said exactly! It’s unbelievably maddening as I have perfected my diet and lifestyle to help me sleep, but it is all to no avail while I’ve been stuck in perimenopause hell for several years now. Please please do a podcast on this or at least ask Matthew Walker to answer this question!

  8. The one major thing everyone is missing here is the influence of electromagnetic radiation (EMR on the body’s sleep cycles. Many electrosensitive people cannot get into REM sleep until all the influences of EMR are removed. How many people that complain about their lack of sleep have their mobile phones by their bedside? Do they turn off the WiFI at night? Better yet, do they shut off all the electrical circuits that surround the sleeping space? Many of my clients are surprised and delighted with a good night’s sleep after they follow these simple instructions. Technology is a wonderful thing but it is killing us in many ways.

  9. fantastic interview (all 3 parts and prior AMA)! this had me restructure my thinking about sleep to respect a 7hr minimum (used to do 5-6hrs avg) and force my wife (w/ broken sleep problems) to get at least 7.5hrs. Thanks!

    BTW, re “True REM is seen only in birds and mammals” add octopi to the exclusive club list:

    Evidence of Sleep Cycle Analogous to Vertebrate SWS/REM Alternation in the Octopus

  10. Very fascinating but can you give recommendations on what to implement to improve sleep pattern!!

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