Dr. Matthew Walker, All Things Sleep — How to Improve Sleep, How Sleep Ties Into Alzheimer’s Disease and Weight Gain, and How Medications (Ambien, Trazodone, etc.), Caffeine, THC/CBD, Psychedelics, Exercise, Smart Drugs, Fasting, and More Affect Sleep (#650)

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“Most of us assume that sleep evolved. But why should we make that assumption? Why isn’t it that sleep was the default state when life emerged, and it was wakefulness that evolved?”

— Dr. Matthew Walker

Matthew Walker, PhD (@sleepdiplomat), is professor of neuroscience at the University of California Berkeley and founder and director of the school’s Center for Human Sleep Science. Dr. Walker is the author of the New York Times and international bestseller Why We Sleep: Unlocking the Power of Sleep and Dreams, which was recently listed by Bill Gates as one of his top five books of the year. His TED Talk, “Sleep is Your Superpower,” has garnered more than 17 million views. 

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. In 2020, Dr. Walker was awarded the Carl Sagan Prize for Science Achievements. Dr. Walker’s research examines the impact of sleep on human health and disease. He has been featured on numerous television and radio outlets including 60 Minutes, Nat Geo TV, NOVA Science, NPR, and the BBC. Dr. Walker is also scientific advisor to Oura, a sleep-tracking ring.

Dr. Walker hosts the 5-star-rated podcast The Matt Walker Podcast, which is all about sleep, the brain, and the body.

Please enjoy!

Listen to the episode on Apple Podcasts, Spotify, Overcast, Podcast Addict, Pocket Casts, Castbox, Google Podcasts, Stitcher, Amazon Musicor on your favorite podcast platform. You can watch the interview on YouTube here.

Brought to you by Eight Sleep’s Pod Cover sleeping solution for dynamic cooling and heating, Athletic Greens all-in-one supplement, and LMNT electrolyte supplement.

The transcript of this episode can be found here. Transcripts of all episodes can be found here.

#650: Dr. Matthew Walker, All Things Sleep — How to Improve Sleep, How Sleep Ties Into Alzheimer’s Disease and Weight Gain, and How Medications (Ambien, Trazodone, etc.), Caffeine, THC/CBD, Psychedelics, Exercise, Smart Drugs, Fasting, and More Affect Sleep

This episode is brought to you by LMNTWhat is LMNT? It’s a delicious, sugar-free electrolyte drink mix. I’ve stocked up on boxes and boxes of this and usually use it 1–2 times per day. LMNT is formulated to help anyone with their electrolyte needs and perfectly suited to folks following a keto, low-carb, or Paleo diet. If you are on a low-carb diet or fasting, electrolytes play a key role in relieving hunger, cramps, headaches, tiredness, and dizziness.

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Want to hear another podcast episode with someone who won’t rest until you get a good night’s sleep? Listen to my conversation with neuroscientist and Stanford University professor Dr. Andrew Huberman, in which we discussed timing circadian biology to accentuate the positive and eliminate the negative, the ideal time for morning light exposure, what he recommends over melatonin as a sleep aid, the non-sleep deep rest of yoga nidra, using physiological sighs to reduce stress, the future of beneficial brain change, cage diving with great white sharks, and much more.

#521: Dr. Andrew Huberman — A Neurobiologist on Optimizing Sleep, Enhancing Performance, Reducing Anxiety, Increasing Testosterone, and Using the Body to Control the Mind

What was your favorite quote or lesson from this episode? Please let me know in the comments.



  • Connect with Dr. Matthew Walker:

Website | Twitter | Facebook | Instagram | LinkedIn


  • [05:55] Sleep and Alzheimer’s disease.
  • [19:55] What causes the decline of deep sleep as we age?
  • [24:36] Are there any known species that don’t require sleep?
  • [29:15] Brain stimulation for more deep sleep, less insomnia.
  • [41:01] Tips for better sleep without laboratory budget or access.
  • [51:45] Ideal types of exercise for promoting deep sleep.
  • [53:51] Matt’s updated thoughts on caffeine and sleep.
  • [1:11:12] Cannabis (CBD, THC, CBN) and sleep.
  • [1:30:18] A crowdsourcing request of listeners.
  • [1:36:17] If the bed’s a-rocking…
  • [1:41:45] The Da Vinci Code magic sleep device.
  • [1:46:04] DARPA innovation.
  • [1:46:32] Ensuring proper function in the glymphatic system.
  • [1:50:42] Psychedelics and sleep.
  • [2:01:20] How sleep affects food intake and weight fluctuation.
  • [2:10:46] Orexin, I reckon.
  • [2:22:11] Fainting goats and narcolepsy.
  • [2:25:36] Modafinil.
  • [2:30:32] How sleep medications affect sleep quality.
  • [2:36:16] Trazodone.
  • [2:46:26] Perilous polypharmacy.
  • [2:49:04] Pregabalin and gabapentin.
  • [2:54:33] The psychological value of emergency sleep medicine for insomniacs.
  • [2:58:16] CBTI and the balancing role of pharmacology.
  • [2:59:56] Parting thoughts and what to expect from a future round two.


“If sleep is a missing piece in the explanatory puzzle of aging and Alzheimer’s disease, then maybe we can do something about it. Sleep is a modifiable factor.”

— Dr. Matthew Walker

“In biology it’s very rare that you get a free lunch. And when you fight biology, you normally lose.”

— Dr. Matthew Walker

“Night after night, if you’re not cleansing the brain, it becomes like compounding interest on a loan, that it continues to escalate time and time again, night after night. “

— Dr. Matthew Walker

“Most of us assume that sleep evolved. But why should we make that assumption? Why isn’t it that sleep was the default state when life emerged, and it was wakefulness that evolved?”

— Dr. Matthew Walker


DISCLAIMER: I’m not a doctor, nor do I play one on the Internet. None of the content in this podcast constitutes medical advice. Please consult your doctor before considering anything we discuss in this episode.

The Tim Ferriss Show is one of the most popular podcasts in the world with more than 900 million downloads. It has been selected for "Best of Apple Podcasts" three times, it is often the #1 interview podcast across all of Apple Podcasts, and it's been ranked #1 out of 400,000+ podcasts on many occasions. To listen to any of the past episodes for free, check out this page.

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13 Replies to “Dr. Matthew Walker, All Things Sleep — How to Improve Sleep, How Sleep Ties Into Alzheimer’s Disease and Weight Gain, and How Medications (Ambien, Trazodone, etc.), Caffeine, THC/CBD, Psychedelics, Exercise, Smart Drugs, Fasting, and More Affect Sleep (#650)”

  1. Very interesting episode and timely. I’ve been taking CBD gummies with 2.5mg of THC to aid in getting to sleep for about the past 4 months. It worked great while I was consistently using. I decided last week to stop usage and focus on alternative methods to improve sleep. I’ve been dealing with terrible insomnia and this past week which is just now starting to show signs of course correcting. Still not to where I was a few years ago when I was getting a healthy night of sleep. (Fast to sleep, quality sleep and sleep duration). This was pre-kids which ultimately led me down the path of sleep aids.

  2. Hey Tim, long time listener, first time commenter. Responding to the inquiry about cannabinoids and sleep. I recently started using HHC for sleep and it has no negative effect on my Oura ring data or my mental status the next day. Sidenote: you’ve inspired me to start a podcast, so thanks for that, and I hope you keep up the good work!

  3. Do you drink milk? It would probably help your sleep. Also I find cranberry or pomegranate juice helps sleep for whatever reason

  4. Tim – random yet only way I could try and get a message to you. I am a random Aussie who loves your work. I am in Austin for Endurance Exchange for work. Thought what better than to meet you, buy you a beer and have a chat. If you are up for it. My mate said, just tell him you do shot differently and he will take notice. 😂 Anyway, if you ar e up for it, please email me.

  5. Hi Tim, after many years with problems with onset and maintenance insomnia, a friend in Brasil gave me a wonderful and simple solution. A tea made of the bark of mulungu – Erythrina mulungu, or Erythrina velutina, both have worked for me – in combination with Camomile. It’s simply a couple of Tb spoons of mulungu boiled for about 15″, then add a tspoon of Camomile flowers, boil for another minute or two, the let it rest. I usually prepare about 1Lt a day in advance and put in the fridge once it’s cooled down. I’ve been taking this continuously for about a year, and my friend, for much longer, with no observable side effects. I couldn’t find the bark in the US, so I brought some from Brasil. I can send you some if you’d like. Otherwise, the powder or extract that that you can find around here will probably work.
    Thanks for a whole lot!

  6. It’s awesome to see all these talks about sleep, it’s very underrated problem many people have. What I hope you could dig into Restless Leg Syndrome (RLS) because it seems to be poorly understood and I’ve been struggling with this for a few years now: massages, cold/hot compresses, light exercise, mediation, teas, warm milk, you name it (except medication). What else is there?

  7. Hi Tim and Dr. Walker,

    I loved this discussion. Every time I tune in tune into Dr. Walker’s research, I learn something that I can apply to my own life/sleep. If that’s not useful research, I don’t know what is!

    I am commenting because you guys discussed a few topics (glymphatics, Alzheimer’s, vestibular equilibrium) that are HUGE in osteopathic cranial manipulative medicine (OCMM). If you are not familiar with OCMM, or osteopathic medicine in general, I think it might interest the both of you deeply.

    VERY briefly, osteopathic medicine is a practice of medicine that focuses on the manipulation soft tissue (mainly bones, muscles, and fascia) to optimize physiological and anatomical health. Every physician in the United States with “D.O.” at the end of their name, (versus M.D.- approximately 15%), has been trained in this type of medicine. Only a fraction of osteopathic physicians actually practice osteopathy extensively, but this is a whole other topic…

    There was one particular moment that prompted me to write in.

    Tim asked Dr. Walker something along the lines of “What can I do to ensure that I am facilitating my glymphatic cleansing response that occurs when I sleep?”… And Dr. Walker, god bless him, responded with something brilliant (as always), but not necessarily an answer to Tim’s question. Dr. Walker said basically that we must sleep to maximize our glymphatic potential, and when we fail to do so, we see a reduction in immune responses to vaccines (a little off topic, but a cogent point).

    Now, to the point about osteopathy, Osteopathic researchers have been on to the idea of optimizing glymphatic flow long before there was even evidence that a formal glymphatic system actually existed. The techniques used in OCMM are specifically designed to optimize precisely what Tim was asking about1.

    Coincidentally, to Dr. Walker’s response, there is some evidence to suggest that other osteopathic lymphatic approaches (not just the ones on the head) have been shown to increase the immune response to vaccines2,3 (of note, there are many studies that have shown no response as well4). The evidence is mixed on this point.

    And finally, anecdotally, I have treated many patients and seen other providers treat many patients (particularly children), who come in after receiving treatment who swear they have never slept so much in their lives! We have even received phone calls of worried parents asking why their child is sleeping so much after treatment and if that’s okay.

    Anyway, I just wanted to reach out because I was screaming in my car while listening, hopping that these points would get brought up.

    I firmly believe there is a physical component to proper glymphatic flow, namely the interface of cranial sutures and the dura, which may end up having a dramatic impact on Alzheimer’s, glymphatic, and possibly even sleep research.

    Please feel free to reach out with any questions,

    [Moderator: contact information removed from post per policy but preserved in intake fields.]

    1- Marino MA, Petrova S, Sweiss R, Duong J, Miulli DE. A Review of Glymphatics and the Impact of Osteopathic Manipulative Treatment in Alzheimer’s Disease, Concussions, and Beyond. Cureus. 2022 Mar 29;14(3):e23620. doi: 10.7759/cureus.23620. PMID: 35505702; PMCID: PMC9056591.

    2- Jackson KM, Steele TF, Dugan EP, Kukulka G, Blue W, et al. (1998) Effect of lymphatic and splenic pump techniques on the antibody response to hepatitis B vaccine: a pilot study. J Am Osteopath Assoc 98: 155–160

    3- Noll DR, Shores J, Bryman PN, Masterson EV (1999) Adjunctive osteopathic manipulative treatment in the elderly hospitalized with pneumonia: a pilot study. J Am Osteopath Assoc 99: 143–146, 151–142

    4- Breithaupt T, Harris K, Ellis J, Purcell E, Weir J, et al. (2001) Thoracic lymphatic pumping and the efficacy of influenza vaccination in healthy young and elderly populations. J Am Osteopath Assoc 101: 21–25.

    apologies for the re-comment, I can’t seem to post.

  8. I find it interesting that there are millions of people who voluntarily take illicit drugs and the two of you discussed testing trazodone on animals after infecting them with the same drugs. Animals are definitely not volunteering to be tortured in this manner.

    As George Carlin so astutely put it, and I paraphrase…One day this beautiful blue planet is going to shake us off like a bad case of fleas to protect itself…we are the poison with our disregard and disrespect of life outside our arrogant selves.

  9. We hear a lot about the importance of sleep and it’s detrimental effects when we don’t get enough or proper sleep. However, there are folks, like myself, that work shift work and it’s simply unavoidable. I work in Air Traffic Control in a 24/7 facility. Most of us work a compressed schedule, meaning we start the week working nights and each day progresses to earlier shifts. They frequently involve “quick turns” where you work a night shift and have to be back in the morning 9 hours later. Also there’s quick turns where you work an early morning shift and return for a midnight shift 8 hours later. It’s a very fatiguing schedule that lasts 20 years. I wish we could hear about ways to sleep hack for shift workers.

  10. Per Tim’s request in the episode, a good book on the history of DARPA is “The Pentagon’s Brain: An Uncensored History of DARPA, America’s Top-Secret Military Research Agency” by Annie Jacobsen.

    However, as someone that has worked on unclassified DARPA-funded projects in graduate school, I found that she gave DARPA more credit for coming up with ideas, while what I saw was a flow of ideas back and forth between DARPA and researchers trying to get funding for their ideas, especially since many of the DARPA program managers are university faculty on a two year leave. I also thought the book sensationalized DARPA more than what I had seen.

    For a somewhat humorous short viewpoint of DARPA from a faculty member that gets funding from them, you can watch the beginning of this talk by my old classmate.
    [Moderator: YouTube video to “Michel Maharbiz, University of California, Berkeley” removed due to embed policy.]

  11. Fascinating discussion and Matthew’s research and knowledge of sleep is really beneficial. However, it would be great if there could be more follow-up on Tim’s reference to desmopressin early on in the discussion and its role in helping with nocturnal enuresis experienced by some young people. It’s a topic and health condition that is never publicly discussed with lots of stigma and shame associated with it, despite great advances in tackling stigma of many of other health conditions.