All Smith Podcast — Full Transcript

Dr. Kirk Parsley: What Sleep Deprivation Really Costs High Performers

Host: Bryce Smith  |  Guest: Dr. Kirk Parsley, Founder of Sleep Remedy

Bryce Smith

What’s up everybody. Welcome back to All Smith. Today is going to be a very fascinating conversation, where we take a deep dive into sleep. There’s a version of fatigue that most people, they simply never touch, and a version of performance that’s built on top of that. Today’s guest has lived both ends of that spectrum.

He’s a former Navy SEAL turned physician and now founder of Sleep Remedy. He went back to the SEAL teams and saw something that most people ironically miss — not a lack of discipline, not a lack of work ethic, but simply a lack of recovery based on the health biomarkers. Most operators train very hard to override biology, but then they get stuck there long after their mission ends.

So today’s conversation is what sleep deprivation actually does to the body, the mind, the heart, and the soul, to the brain, to the hormones, and specifically to the nervous system, and eventually a life inside one of the most elite performance cultures on earth. Sleep seems to be one of the biggest challenges. So, today we’re going to dive in with Dr. Kirk Parsley. Stoked to chat it up with you today, man.

Dr. Kirk Parsley

Yeah, likewise. Thanks for having me on.

Bryce Smith

Sleep, it seems to be a cliche word that’s floating around all kinds of biohacking culture, all the doctors, all the podcasts, but because it’s so simple, most people are simply just kind of overlooking it. They’re like, oh, I’ll worry about it later. Until they see a doctor and they get a peek under the hood, they see biomarkers or they start using a data tracker based on actual raw data, they eventually start to change — but what is it about sleep where high performers specifically think they can get away without it?

Dr. Kirk Parsley

I mean, specifically in my culture, the SEAL team culture, one of the things we learned during BUDs is that you can go for a week without sleep — so sleep is obviously a luxury, right? In fact, when I started working with the SEALs as their physician, they came and listed out all of these problems they were having, which ultimately turned out to be largely linked to sleep. But not a single one of them said anything to me about not being able to sleep well.

And I work with entrepreneurs, C-suite executives, CEOs, multi-billionaires — they all seem to think the same thing: you have to outwork everybody if you’re going to be on top. You have to be the first one into the office, you have to be the last one out. And if they all think that, well then their competition just keeps spreading, and everybody keeps thinking working harder, working harder, working harder.

In the SEAL teams, we used to say that you could do anything you wanted to, you just had to put your head down and run harder. And I think that’s kind of the belief system of most hard-charging, ambitious, especially young men — but I think women as well.

Bryce Smith

When you look at that, man, the world is romanticizing it, because there’s validation around “more is better” instead of “better is better.” It works in the beginning because you’re going from probably not as much competition, and you start to get exposure to other SEALs or other people in pursuit of being the 1% of the 1%. And when you relate that to entrepreneurship, to competition in the world, inevitably people are going to try to find their edge. Like, okay, I’ll sleep when I’m dead. Pain is just weakness leaving the body.

“Who’s going to carry the boats,” waking up at 4:30 in the morning gets romanticized by Jocko, and all these things work to get you to that top-in-your-field element. But the thing that’s interesting to me is it works until it doesn’t work anymore. I think if we can create this psychological understanding around seasons — hey, there are seasons for sprints, there are seasons to back off, rest and digest — there needs to be a psychological and physiological understanding that if your nervous system is constantly in fight or flight and not sleeping, inevitably the batteries are going to run out.

But that’s the side that gets highlighted, the trophies and the pat on the back and the notoriety. The sleep and the rest-and-digest side is kind of like, “oh, I’ll sleep when I’m dead.” How do you reframe that ideology when somebody used that element of discipline and work ethic to become so successful, and then all of a sudden it’s not working for them anymore, and they’re seeing a depreciation in their performance?

Dr. Kirk Parsley

Yeah. Well, not to self-aggrandize, but when I first started talking about this back in 2009, I literally got laughed out of the room when I was telling people that their hormones were low because they weren’t sleeping well. When you’re 20 to 25 years old, and you’re metabolically and physiologically so resilient that you’re just really hard to kill, and you can recover from anything — you can do stupid things, you can make poor choices, not just with sleep, but with how you train and how you eat. Things just aren’t as consequential when you’re young and very resilient.

I always like to get rid of this cultural idea about “super sleepers.” What you’ll hear in the media is that genes have been discovered that show some people don’t need to sleep as much as others, significantly less than others — and that’s not true. What the research actually shows is that those people don’t suffer as much as everybody else when they don’t sleep as long as they should. Seven and a half to eight and a half hours, plus or minus about 15 minutes, is really the right amount for about 99.99999% of society. The odds that you have this super-sleeper gene are about the same as getting struck by lightning and attacked by a shark at the same time. It’s about 0.00003% of the population — and even then, they’d still be better off if they slept more.

The biggest problem I came across with the SEAL teams, and what I continually come across today even with a lay audience that’s way more educated on sleep than they were 16-17 years ago, is people thinking they’re okay not sleeping as much as they should. But the research shows that our introspection, our own self-assessment of how well we’re doing, is impaired by sleep deprivation. It’s very similar to alcohol. If you’ve seen my TED Talk, I give this metaphor: what if your surgeon took a shot right before doing your surgery? You’d be freaked out, right? But there’s been a lot of research showing the comparison between intoxication and sleep deprivation, and it parallels really well — decision-making errors, neuromuscular coordination, endurance, muscular strength, all of that decays as you deprive yourself of sleep, just like it decays as you get intoxicated.

But what also decays in both of those is your own self-assessment. After four or five beers, you’re like, “I’m fine, I can do whatever I want, I feel like Superman.” And when you wake up with inadequate sleep, your body compensates by secreting more stress hormones — cortisol, which elevates your blood glucose, and norepinephrine and epinephrine, which is adrenaline.

Dr. Kirk Parsley

That gets secreted, and you feel pretty good, especially if you have some loud, obnoxious alarm that shocks you out of sleep. You’re maybe two-thirds of the way up to fight or flight, as far as how your adrenals are reacting. If you’ve ever been in a fight-or-flight situation, you feel very alert, very capable — you’re not going to fall asleep during a fistfight unless you get knocked out. You’re not going to fall asleep during a car crash, or if somebody’s shooting at you, or if you’re being tracked by a tiger. Fight or flight does make you feel superhuman, and you are superhuman while you’re in it — it’s the maximum adrenal response you’re capable of producing. The only thing that really gets impaired in fight or flight is your prefrontal cortex, your decision-making executive skills. But your lungs feel better, your cardiovascular system improves, your cardiac output improves, your blood glucose goes up, your alertness goes up, your pupils dilate, your pain threshold goes up, your reflexes get faster, your endurance and strength increase — you’re superhuman.

But the cost of fight or flight is that you’ve shut down everything anabolic — all the digestion, all the recovery, all the repair — and you’re using your body’s own resources as the fuel to get through that stressful situation. If you run around 50% of the way there all the time, you’re continually using your body as a fuel source, which is a catabolic activity that makes it hard to maintain good body composition and energy levels. It also impairs the prefrontal cortex — your emotions, decision-making, cognition, memory, executive function, all of it.

Bryce Smith

Yeah, it’s very well said, so we can get a better understanding physiologically as to what’s taking place. But I’m still curious — guys operate this way and get away with it for quite some time, so cognitively it’s downloading an operating system that’s creating proof of concept that seemingly is reliable. Most guys get away with it, I’d assume, from age 17 to 28, close to 30, and then all of a sudden their adrenals start to shut down. And they might get away with it a little longer, because there are different forms of caffeine, guys using Zen all the time now especially in the military community, nicotine tinkering with cognitive function.

And then you get liquid courage being alcohol, and then you get —

Dr. Kirk Parsley

Well, and Adderall and Modafinil, and then —

Bryce Smith

You look at all these things that mask the biological and physiological response, and that works for a really long time. You’re like, ah, I’m just feeling a little off today, just need some meds to get over the hump. And now that I’ve coached quite a few of these guys, had in-depth conversations with former SEALs who’ve transitioned into this next chapter of life, former athletes too, the cognition changes, man. It’s like — if I would have just surrendered sooner and realized I couldn’t keep having those California burritos and smashing energy drinks three or four times a day, staying up late with the boys, going to grab six to eight beers, but still waking up for that 5:30am muster. And then when I should be resting during the day, I got addicted to doom-scrolling because I was just looking for escapism. As a byproduct, you get away with it until you don’t. So from a very stubborn, high-performing, high-testosterone place, the ego hasn’t been deconstructed yet for a lot of these guys. I’d argue they get romanticized by their feelings — I feel good, why should I listen to you — and it becomes confrontational, this social hierarchy, as opposed to surrendering to the fact that coaches, doctors, scientists have graduated past that feeling and now understand the reality of, quite frankly, aging.

Dr. Kirk Parsley

Yeah, there’s a lot in there. Like you said, you can compensate for as long as you can compensate. But the way I’m motivated — when I showed up to the SEAL teams as their physician, they already knew SEALs had a problem with anabolic hormones. They knew their anabolic hormones were low, their catabolic hormones were high. Nobody knew why. Everybody was a little hush-hush about it, figuring it was probably guys who’d abused steroids in the past, so nobody wanted to make a big show of it. I’d been a doctor for three, four years when I showed up to the SEAL teams, and I’d never had a single class on sleep in medical school. I didn’t know anything about sleep that anyone else in the community didn’t know. I went through BUDs, I went through Hell Week, I went through residency — I thought sleep was kind of optional too.

When I started researching what sleep actually was — primarily because they were all taking Ambien, and I started digging into what Ambien even does, how it helps with sleep, what sleep even is, since I didn’t really know other than “you went unconscious” — I started learning about the side effects of Ambien, and I started thinking, well, pretty much all these symptoms could be explained by poor or inadequate sleep. I wasn’t naive enough to think it would explain everything — the SEALs do have a big component of traumatic brain injuries, overpressurization, blast injuries is a big problem in our community, so that’s a component too. But the first thing I did was get everybody off Ambien and get everybody to minimize their drinking, do their drinking earlier, make sure they stayed hydrated. And we were tripling and quadrupling guys’ total and free testosterone, tripling their IGF-1, dropping their oxidative and inflammatory markers. Guys felt great, guys were hitting PRs in their early 40s, because they’d been beating themselves down so long and everyone’s testosterone was low — the whole community, because everybody was chronically sleep-deprived, chronically over-trained, and chronically undernourished. It was a massive problem.

But something you alluded to at the beginning — it was our culture. We had cultural norms that everybody kind of felt the same way, and everybody figured out ways to compensate. For example, every SEAL carried a backpack everywhere he went, with everything he needed, in a very specific place every single time. The reason for that is because if he didn’t carry the backpack, he forgot everything.

He’d leave his house, realize he forgot his badge, go back in, get it, start leaving again, realize he forgot his lunch or whatever — leaving the house three or four times before actually getting where he was going. They all became hyper-organized with these backpacks and took them everywhere. But then they get out of the military and go into the generalized business culture, trying to live like 25-to-35-year-olds they’re competing with for jobs, and they don’t have all their compensatory techniques anymore. Their culture is different, their schedule is different, and that’s when guys really start noticing deficiencies in their performance — “man, I really kind of suck, I’m forgetful, I’m having a hard time concentrating, I come unprepared a lot.” They start noticing that the compensatory techniques they used to use, which were super important to their life, aren’t there anymore — because they were immersed in the culture and didn’t know it.

Bryce Smith

Yeah, it’s well said. There’s a statement I’ve heard time and time again — you always put things back in the same place, you never have to wonder where they are. And that works when there are guardrails, which the military does a phenomenal job of: hey, there are two ways to do things, and there are consequences when you don’t do them the right way, especially if you make the same mistake over and over. I think that aligns with — if you want to predict behavior, you have to have some sort of incentive. If you put things back in the same place, you’re going to be on time, you don’t have to wonder where it is. The reward is consistency, you don’t have to think about it, you can use your brain capacity for other things — passing that exam, packing your parachute, whatever’s associated with the current system of training.

The problem is, when you get into the real world, nobody’s looking over your shoulder telling you what to do. There’s no consequence if you don’t make your bed, and the philosophy psychologically becomes: I had structure my whole life, I don’t really want structure anymore, I kind of want to screw off a little bit, I want freedom, I want space. Most guys want to grow a beard at that point, wake up late, do what they want, when they want, how they want — which is totally fine, everybody deserves a vacation from it all sometimes.

Dr. Kirk Parsley

Yeah,

Bryce Smith

But it’s when that escapism starts to bleed that I think the real cognitive dissonance starts to take place. You start to romanticize your time in the SEAL teams, your time as a pro athlete, your time when you were younger, and as a byproduct, depression and anxiety starts to come in. Back in the day I had X, Y, and Z things — you’re worried about the future because you don’t really know the bridge and transferable skills. So I go back to the concept I’m very curious around: buy-in. Because sleep is free, and telling somebody to sleep more, they’re like, “I’m paying you this much,” or “my insurance is this,” or “I have to set up these appointments and you’re just telling me to sleep” — but it’s probably the most valuable thing on the planet that most people don’t do, and if they did, it would unlock so many amazing things for their future.

So real quick, to summarize — you talked about once you got guys away from Ambien, away from alcohol, and put more time and attention into sleep, they started experiencing PRs, better body composition, less inflammation, less brain fog, better quality of life. But I’d assume right at the beginning, since they’re so used to relying on the Ambien and the alcohol, they probably have a significant decline — they might get the shakes, they might have withdrawals that first two to three months, experiencing a decline in performance and more negative symptoms. How do you manage that and create the buy-in for a future that’s a little more delayed gratification?

Dr. Kirk Parsley

Yeah, well, I don’t really know if I could have gotten by if we’d had to go through something like that, so I was very careful about how we went about changing the lifestyle. Now I’m a performance optimization physician, that’s what I do with private clients — 95% of it is lifestyle, and then we do hormones and peptides and hyperbarics and saunas and ice baths and all that other stuff. But we can add in all the seasoning at the end — sleep, nutrition, exercise, and stress mitigation is how you maintain a healthy life. Fortunately, by the time the SEALs started coming to complain to me, we’d already hired a nutritionist and a strength and conditioning coach, so we had somebody programming their exercise, which was way smarter than anything we’d ever had when I was a SEAL. We have this saying in the SEAL teams — moderation, moderation, moderation, and even then only in moderation.

Regardless of what the pharmaceutical industry will tell you, Ambien is highly addictive — it’s a very hard drug to come off of psychologically, because people believe it’s helping them sleep. It doesn’t help you sleep at all. You actually end up getting less sleep with Ambien — you fall asleep on average 24 minutes faster, sleep averages 17 minutes longer, but REM sleep declines by 80% and deep sleep declines by 20%, so overall it’s a net negative. But it dissociates you and makes you not remember lying in bed awake, so you feel like you’ve slept more, and people get psychologically addicted to that. The most common reason for insomnia is that you can’t sleep because you’re worried you’re not going to be able to sleep.

So instead of just cutting their Ambien cold turkey and causing a freak-out session, I converted their Ambien to a serum through a compounding pharmacy, where 10 drops was a full dose. They’d do a week of 10 drops, a week of 9, 8, 7, 6, all the way down. Then I gave them a list of supplements to take before bed, which is what later became Sleep Remedy. And I’d have them decrease their alcohol intake and do it earlier — I wouldn’t try to tell a 28-year-old SEAL to quit drinking, that’s a non-starter. But if he was having six beers a night, I’d say, “What if you try to cut that back to maybe three, then two, then the occasional one.” It was a protracted thing.

How I motivated them was by doing labs — a full 98-panel of markers, basically every lab I knew how to interpret — and I could show them their progress. I could honestly tell the vast majority of guys who came into my office, “You have the free testosterone of a nine-year-old girl, and you’re a Navy SEAL trying to carry 200 pounds on your back and jump over a wall and kick in a door — this isn’t going to work.”

The traditional doctor in me was trained to recognize and treat disease, and what my community would have said is: if their testosterone is low, give them testosterone; if their inflammation is high, give them Motrin. But I wasn’t allowed to give them testosterone — SEALs have to be forward deployable, they have to go to austere environments, they can’t be dependent on any medication. If you give them something they need to use every day, they’re incapacitated by definition when they don’t have it, so they’re not deployable, they can’t really be SEALs anymore — and they’d rather die than be pulled out of their job. So we did it very gradually. Most of the guys who came into my office had been suffering four, five, six years, so what was another three months to see gradual improvement, instead of trying to cut everything off cold turkey. Even with private clients, I find it too disruptive to the psyche to cut things off cold turkey, whether it’s benzos or Z-drugs or whatever they’re using as a sleep aid. I usually titrate it down at the same time as teaching sleep hygiene and sleep tactics and strategies for when they do have insomnia.

Bryce Smith

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I love your approach — I actually think dosage is one of the hardest things to manage when it comes to medications, and I like that you measured it in drops, in a tincture form from a compounding pharmacy. That way they’re not sitting there cutting an Ambien into pieces, which obviously isn’t consistent. Your psychological approach in a world so fascinated with outcomes — there has to be the conversation around the business side of things. Were you covered by the VA? Were you a cash-only private practice, like most SEALs want? Results — then what — results fast, so testosterone is a quick fix until it’s not. And I think what you described as being incapacitated, because now you’re reliant on a medication which diminishes your ability to perform your job at a high level if you don’t have access to it, especially on longer deployments, and from my understanding, most of those medications need to be refrigerated too, so transport can be difficult.

Dr. Kirk Parsley

All the peptides pretty much need to be refrigerated, yeah.

Bryce Smith

Sure. So based on that, how did you create lifestyle understanding? I think your timeline is spot on — most guys, for about four to six years, are like, “I’ll just keep grinding, I’ll keep trying to fit a square peg in a round hole, I’ll do what I once did and see if it works.” Over time, especially modern day, they’ll listen to a podcast, try a couple changes, usually half-ass those changes, and go “it didn’t work,” and try the next thing. Some things work a little, some don’t, but they’re kind of addicted to the feeling — I feel good, I feel this, I feel that — versus getting real data that gives you a long-term result rather than a short-term burst. But the mind is very much like short-term memory — what have you done for me lately, whether that’s a human, a coach, a doctor, or medication — and when something seemingly stops working, I feel like high performers have the ideology of “find what works and do more of it; if it stops working, change course.” So for guys who want those quick results, do you have the conversation of — hey, what you were doing wasn’t working, which is why you ended up in my office to look at your labs and have a course of action that’s going to upgrade your operating system, because if nothing changes, nothing changes. Do you want to go back to the last four to six years, or do you want to make the rest of your life the best of your life? And that starts with taking ownership and accountability, consistently providing honest feedback, and being able to wean yourself off the Ambien and the alcohol and the things that are toxic to the system. But how is that process for you — are guys in so much chronic pain and depression that they’re just willing to try anything at that point?

Dr. Kirk Parsley

Yeah, when I was actually at the SEAL team as their physician, many of those guys would have liked help years before, but they weren’t willing to trust the medical profession to help them without disqualifying them, so they were trying to do things on their own or just push past it. However, they were exceedingly motivated — desperate to get back what they had. Now, honestly, we do age, and performance does decline over a lifetime, there’s no way around that. I was a competitive powerlifter for years, and at 56, every lift I have now is depressing compared to my prime — so now I have different goals. But these guys were still actively working as SEALs, still comparing themselves against other SEALs, and I could show them — everybody who came into my office got a three-hour lecture about what sleep does, how sleep affects hormones, when your hormones are made, what anabolic and catabolic hormones were, how sleep deprivation and Ambien and alcohol were each impacting things.

It’s a very word-of-mouth community — one guy starts getting help from me, sends his buddy, sends his buddy — but now they’re all competing against each other too, not just on what I’m intervening on, like decreasing alcohol or titrating off Ambien or increasing time asleep or taking naps between training blocks. When I was a SEAL, we didn’t have cell phones, so when we had a break in training, that’s all anybody ever did during downtime — take a nap. Then I’d show them their own labs — “look, your total testosterone went from 300 to 900 just from these changes, your free testosterone tripled” — and explain the anabolic effect. Of course they feel that, they start feeling more vigorous, they feel like they can work harder, and then they’re competing with their buddies about who has the highest testosterone, who can get the best lift.

I still work with SEALs today. I’ve never charged a SEAL for my time, and I never will — I work with them through a foundation. There are foundations that will pay for all their medications, peptides, any treatment I prescribe, hyperbarics, stem cells, whatever. My time I don’t charge them for, and my wife does the same for their wives — that’s our philanthropic work. The reason I point that out is because these guys are no longer competing against other SEALs when they come out — most of the guys I see are retired.

They’ve spent 20-plus years in the SEAL teams, had six to ten surgeries, hundreds — perhaps thousands — of head injuries, overpressurization, blast injuries. And they come to me through word of mouth, they know who I am, I’ve helped one or two or three of their buddies, so they trust me. But I start from square one — “I know you’re going to be resistant to this, but everything I have to offer you — pharma, supplements, peptides, hormones, hyperbaric, light treatment, laser therapy, shockwave, saunas, cold — none of that adds up to getting good, quality sleep and having a healthy lifestyle, which is orders of magnitude more powerful than all of those other things. If you aren’t willing to do that, then we’re not going to be successful, and we should go away as friends before we disappoint each other.” I’ve had guys say, “I’m not ready to do that.” Okay, then we don’t do that, that’s just the way it goes — sometimes they come back later, sometimes I never hear from them again. I harp on everyone, I don’t care how elite they are — I work with professional athletes too, those are the guys who actually pay my bills, and I have the same conversation with them. My screening questionnaire is about four pages long, and there are five or six times in there that say you have to be willing to spend eight hours in bed every night. I reiterate that over and over. That’s how I go about it.

Bryce Smith

I think it’s really cool that you have that upfront, honest conversation, because man, humans are such great justifiers — I can’t sleep because of my new kid, my responsibilities with this or that, my workflow — there’s a lot of pushback. But at the end of the day, from so many doctors and experts I speak to, sleep seems to be the number one cheat code, and unfortunately creating consistent buy-in around that is incredibly difficult. It seems to be the most effective thing you can do to reset your brain and body, and even saying that, people are like “whatever, I don’t want to do it because of X, Y, Z.” I think it goes back to that conversation about seasons — if sleep becomes a major priority, you actually build yourself buffers for the more challenging seasons. What are your thoughts on that? Using Hell Week as an example — minimal sleep exposure, circadian rhythm thrown off, decision-making gets tough — but you could relate that to a brand-new parent, or someone in the first stages of entrepreneurship. Not exactly the same, but there are relatable characteristics. How do you help people understand this concept of creating buffers, and what advice do you give to maximize their maybe-limited exposure to that eight-hour window in bed?

Dr. Kirk Parsley

Yeah, I’ve probably done several hundred lectures to first responders, who always have a shift-work component — people sleeping outside their circadian rhythm, not getting enough sleep. I always preface it by saying, I do this for a living, this is my expertise, and I’d say five out of seven nights every week I don’t really want to go to bed when it’s time. I really wish I could stay up, but I know what the better solution is. The most important thing, before we even talk about specific seasons or techniques, is that people understand how important sleep is. Once they understand that, they can usually find a way to do it. If I’m only getting them to adjust their schedule because I’m telling them sleep is important, that usually doesn’t end well — because that’s just my voice, and all they have to do is quit taking my calls and that noise is gone.

What I usually tell people is: sit down, talk about your goals, your ambitions, your values — take those, go to a credible source, Google Scholar or PubMed, and put in what you care about plus sleep — parenting and sleep, cognitive functioning and sleep, emotional intelligence and sleep, physical performance and sleep — and read until you’re petrified, until you realize you’re a total fool for not getting sleep, that it’s the most important thing in the world. Once you buy that concept, you’re going to be creative. I don’t know your life, your day-to-day — you could never fully explain it to me — but you’re the best coach you have for sleep, you’re the one who’s going to figure out what you can and can’t do.

I use a few guiding principles. I tell new parents — the way the science breaks out, if you have a newborn, both parents are going to lose six months of sleep in the first two years combined, 25% of your sleep. That’s just the way it goes. Shift workers always want to ask me how to make two plus two not equal four — because shift workers die earlier, have more disease, more heart disease, more strokes. I’m not doing shift work, because the only way around that… but for new parents, you don’t both have to lose six months of sleep — you could take turns. It’s very unsexy, but maybe one of you sleeps in the basement or spare room with earplugs, an eye mask, a white noise machine, a fan — one person gets a great night’s sleep, the other deals with the kid that night. That’s one way around it.

Dr. Kirk Parsley

For shift workers, I coach on things they can do to mitigate — block the blue light the last three hours of your shift, go home, get as much sleep as you can, as soon as you can. That’s usually tough buy-in because most shift workers come home when their family is getting up for school. There are always going to be challenges — people who do business overseas on a six-hour phase shift and have to get up super early or stay up super late and can’t prevent that. All I can tell you is you’re making a choice that has consequences, and I can teach you techniques to reduce the impact by maybe 25%, or best case 50% — but if I can instill in you that sleep is the most powerful performance-enhancing tool you have, the most powerful longevity tool there is —

The only time you’re recovering is while you’re sleeping. That’s it. When you work out, you don’t get stronger — you get weaker. When you sleep and recover, you get stronger. When you push your aerobic capacity, you get worse; when you sleep, you recover and get better. When you learn something, you hold it in short-term memory, and various emotional categories, and then when you sleep, you convert it into long-term memory and compare it with other information you know. Your emotional intelligence is completely dictated by how well you sleep, because sleep affects your cognitive and emotional energy for the next day, but it’s also when you’re emotionally categorizing everything that’s ever happened in your life. If you’re getting chronically bad sleep and not categorizing things well, emotional triggers get bigger — the amygdala, the region that dictates fight or flight, becomes hyperactive, everything becomes more threatening, your communication gets worse, your trust of people gets worse, you become more hyper-vigilant, which creates more stress hormones.

Once you convince people that they’re destroying their life with their choices, and I’m here to tell you the truth — you can improve marginally with all these techniques, we can use peptides to encourage circadian alignment or improve cognition or protect brain cells or increase growth hormone — but those are small levers. The big lever is the lifestyle. I used to teach that there were four pillars of health — sleep, exercise, nutrition, and stress mitigation. I’ve shifted that slide now: there’s exercise, nutrition, and stress mitigation, and they sit on the platform of sleep — because if you aren’t sleeping well, none of that other stuff works, and sleep enhances all of it, and doing those things well enhances sleep as well.

Bryce Smith

That’s awesome, man. I like that you put those three pillars on top of the platform of sleep. I also think it’s important to note, for people who might just listen to a portion of this podcast or clips rather than the long form and gain total context — you don’t get results from the work you didn’t do. People decide, “I’m going to sleep all the time,” and they’re not actually doing the work, not doing the job. You still have to recover from some sort of stress — physical stress from working out, or your job, writing a brief, editing something — you still have to do all of those things, and optimal sleep, roughly seven to nine hours, can make all of that better, but you still have to put in the work. Can you help people understand that a little more? Because right now we’re in this “oh, Bryce and Dr. Kirk talked about sleep, if I just sleep, the rest of my life will be the best of my life” moment — for people who innately put in the work, that’s going to work phenomenally, it’s the secret ingredient that’s been missing. But for a lot of people, they’re not actually putting in the work, they’re kind of coasting through life, playing with distraction and dopamine addiction, and not sleeping — so the brain becomes cognitive mush that’s really unmotivated. What are your thoughts and advice around that narrative?

Dr. Kirk Parsley

Yeah, so as you alluded to — becoming the person you’re meant to be, living the life and purpose you believe is the highest or most desirable purpose for your life, that all requires growth. And the only reason anything ever grows is due to resistance. Why do astronauts lose all their muscle and bone mass in space? Because there’s no more resistance. You have to continually push against something to be growing — that’s a basic foundational adult concept. If you don’t have that yet, maybe get some sleep, get your brain in good order, and work on that.

But the metaphor I give people all the time: think of sleep as a repair system. Say you’re really high performance, doing Baja racing, jumping sand dunes at 100 miles an hour, making crazy turns, damaging the vehicle. When you go to sleep, a team of experts comes in and fixes that vehicle for you the next day. If that team doesn’t come in and do that, how long do you think that vehicle is going to perform well? It’s going to collapse. The whole reason I’m going to sleep tonight is because I’m using resources today and damaging myself today. I worked out this morning, I damaged my muscles — they’re weaker than when I woke up — and the only chance of them getting stronger is tonight.

I might twist my ankle, bang my knee, I’m definitely going to deplete ATP in my cells, deplete glycogen stores, deplete neurotransmitters, build up waste products — all of that has to be repaired. So I have to repair, and then I have to prepare, because tomorrow is going to come at exactly the same time no matter what I do. It takes about eight hours to repair and prepare for tomorrow — restocking the shelves, putting all the constituent elements back into every cell, building ATP stores back up, ramping mitochondrial function back up, clearing out the bad stuff, repairing the damage, and preparing for tomorrow. The best I will ever be is after a good night’s sleep, and my day is going to start at exactly the same time no matter what — the sun comes up at the same time, my responsibilities are the same. So if I decide to sleep six hours instead of eight, when I need eight to repair, that’s just the way the world works. If I stay up two hours late watching some stupid show that has no value to my life, I’ve just decreased my preparation for tomorrow by 25%, but tomorrow’s still going to come at exactly the same time.

Dr. Kirk Parsley

I still have to do exactly all the same things, so if my team didn’t repair my truck, but I still have to race it tomorrow, how do I compensate? As a driver, maybe I drive more slowly, take corners less aggressively, whatever I can do to compensate for the vehicle not being ready. As humans, we compensate by secreting more stress hormones, which make us feel alert, raise our blood glucose, ramp up ATP production, make us feel a little more alert and better — but those are catabolic hormones, they’re eating you, using you as a resource. Instead of having all the amino acids you need in every cell, you’re eating your muscles as an amino acid store to get everything your cells need.

Once you truly value sleep and understand that sleep is repair, sleep is recovery — those are completely indistinguishable terms. You can rest during the day, but you can’t recover during the day, because every cell in your body — a lot of people think circadian rhythm is just about aligning your sleep time with your eyes and blue light, about your brain being asleep. No — every single cell in your body is on the same circadian rhythm. Your liver cells do different things while you’re asleep than while you’re awake, or at least at different rates and priorities. Your heart cells, your muscles, your brain cells — being awake and being asleep isn’t just a state of alertness that we can measure, there’s a physiological difference in every cell in your body, and that’s when the repair crew is working on your vehicle.

If you don’t do that, the repair simply doesn’t happen, and you’re going to duct-tape it, bail-wire it, 550-cord it, and try to compensate and keep your vehicle on the road — but it’s obviously not going to last as long or perform as well. You’re doing the same thing to yourself. And if that’s okay with you, if that’s aligned with your goals, that’s fine with me too — I’m not here to tell you what your goals ought to be, but I am here to tell you the truth, and the physiologic truth is that you cannot operate at your best without sleeping well.

Bryce Smith

I love that analogy, man — the team going in and repairing your vehicle for the Baja 1000 is really cool. It’s also so true that so many of us want to duct-tape things just to fix them real quick. You know the famous line in a garage or automotive place — if you don’t want it to move and it’s moving, duct tape. If you want it to move and it’s not moving, WD-40.

Dr. Kirk Parsley

Yeah, I haven’t heard that, but I did grow up believing that duct tape, vice grips, and WD-40 could fix anything — maybe a little bailing wire here and there.

Bryce Smith

It’s funny to think about, and I think it’s important to highlight for people that 24 hours awake mirrors the cognitive impairment of legal intoxication — it minimizes your decision-making, makes you a step slow, a day late and a dollar short, maybe coming around a turn, needing to respond appropriately, you’re probably triggered a little more, and your threat detection and reaction time out in the field is now putting not just yourself at risk, but your team too. It’s so interesting how sleep seems to be one of the most important things for high performers, but it’s the first thing sacrificed — and it works to get things going,

Dr. Kirk Parsley

Always, it —

Bryce Smith

Always is, and it works to get things going, but it doesn’t work to keep things going, and I think there’s a big differentiator there. Why do you think operators really struggle to downshift at nighttime? Is it ruminating thoughts, anxiety for the next day? I’d argue sleep is the greatest setup for a green light the next day — almost like getting the coffee beans in the coffee maker so in the morning you just press go, rather than cleaning out the old filter and going through the whole process, getting yellow and red lights along the way. What is it about high performers and operators that makes it hard to downshift into that parasympathetic nervous system at night?

Dr. Kirk Parsley

There’s a lot of nuance, but if I had to lump it into a category, I’d say it’s all performance anxiety, because they’re all competitive. What’s the worst thing for a billionaire? Lose money. He can have all the success in the world, but lose money and he feels like a total loser, because he measures himself by money — nobody pushes that hard for a billion dollars unless you really use money to measure yourself. A SEAL going into training the next day, feeling like a dirt bag, performing poorly, his peers looking down on him — that’s the worst situation in the world for him, to lose the respect of his peers. Professional athletes — very clear metrics, you did your job well and you won, or poorly and you lost, and your employment prospects aren’t great next year. Business owners — a lot are money-driven, but a lot are business-scale driven too, wanting to outcompete their competitor by 30% or 50% this year. So when they go to bed at night, they’re thinking about how to perform better tomorrow, trying to get ahead of it, or they’re tired and fatigued and want to sleep, know they need to sleep, and are now really worried they’re not going to get enough sleep and will perform poorly tomorrow — and that anxiety keeps them up too.

I have a really simple worksheet I do with people. The setup is rote, something you practice — the cognitive behavioral therapy component clicks in whenever it clicks in for you, different for everybody, but it’s usually two to six weeks of practicing these tenets before it clicks into place. Essentially, you have to prepare for going to bed — one of the preparations is understanding that if the whole reason you’re in bed is to perform your best the next day, how do you measure that? First, you make a to-do list — anything you’re likely to worry about, as far out as you’re likely to think about it. For me, that’s about noon tomorrow; for my wife, it’s the next six months. Then a to-worry list — anything you’re likely to think about that you don’t have any control over, but you know you’re going to worry about it, and we don’t want to rob you of the opportunity to worry about it. You make these two lists, and then you make a mental agreement with yourself — this is where the CBT comes in, you have to rehearse this over and over. By definition, those two lists are the most important things to you — otherwise they wouldn’t be the things keeping you awake at night.

The best I will ever be is after a good night’s sleep, and that’s when I should be attacking this list of the most important things to me — that’s tautological, a very simple thing to get behind. You spend eight hours in bed whether you’re sleeping or not, because the next best thing if you’re not sleeping is what Andrew Huberman calls non-sleep deep rest, NSDR. We used to call it meditation, or prayer, or relaxation techniques — a really good meditation state is very similar to a prayer state, very similar to breath work, you can get down to close to a theta brainwave state, the same as stage three of sleep.

Dr. Kirk Parsley

You get in bed with this list next to your bed and a pencil, so that if you think of something that’s not on your list, you have permission to get up and write it down. But the agreement is: from the time you get in bed until the alarm goes off in the morning, you don’t look at the clock, you don’t care what time it is, and you lay there and rest, relax, pray, breathe, do whatever gets you into the deepest state of relaxation you can be in — or you’re sleeping. Either way doesn’t matter, because if you aren’t sleeping, the next best thing is meditating or praying, and when the alarm goes off, you’re as prepared as you’re going to be regardless of what else happens. You can’t lay in bed and think about your to-do list or worry list, because you’ve made the agreement you’re not going to — it doesn’t make sense, you can’t do anything about it right then anyway. The best you’ll ever be at handling that list is in the morning, so if anything pops into your head, “that’s on the list, I’ll think about it when I get up.” Right now, I’m going to relax, meditate, do breath work, progressive muscle relaxation, whatever I want to do. If I wake up in the middle of the night, go to the bathroom, come back, I don’t look at the clock, I lay there and start relaxing again. If the alarm goes off 30 minutes later and I didn’t fall back asleep, well, I slept seven and a half hours and meditated for half an hour — ready to go. If the alarm’s not going off for four more hours and I lay there relaxing, I’m going to fall back asleep — there’s no way around it, you’re not going to lay there and meditate for four hours straight.

That’s how I break that pattern. The performance anxiety is just a generalized category of all of that — people have insomnia because they’re worried something might come tomorrow they can’t handle, essentially. That’s generalized anxiety, worried about the future, or the most common reason: they know tomorrow’s important, they know they aren’t well rested, and they can’t sleep because they’re worried they won’t be able to sleep.

Bryce Smith

Yeah, I think that list is very important — getting things out of your mind and onto paper. Writing fills the gaps within our thinking, makes it tangible, versus “oh, I don’t know why I couldn’t sleep.” It’s kind of like documenting your food — it lets you really see and data-track to get a clear vision of the decisions leading to positive outcomes, negative outcomes, or stagnant, mediocre outcomes. That’s a really awesome approach, and it takes a ton of discipline to lay there and not get on the phone. The thing I hear a lot is, “well, I couldn’t sleep, so I figured I’d just get up and start being productive,” and I think the story we tell ourselves is what holds most of us back. How do you manage that story for people — either that example, or the one where “once I get up, the world’s really noisy, my phone’s going off, tons of demands, I’m basically walking around with a fire extinguisher putting out fires”? So I choose to get up between two and 3am so I can get some movement, some meditation, get my son a cold plunge, get my breathwork, have peaceful coffee, take my morning shit, then attack the day — that’s a really long time to warm up the system. Imagine a strength and conditioning coach programming an hour warm-up before you even get into the workout. If you’re having to take an hour to warm up, I think we need to self-reflect a little more, and that’s where you look in the mirror around sleep, in my opinion.

Dr. Kirk Parsley

It’s funny you should say that — at my age, warm-ups and preparation take more and more time. Your warm-up and mobility work before you actually start lifting anything heavy does get progressively longer. I was recently working with a client who said, “by the time I get through my warm-up and mobility work, I’m too tired to actually work out” — though he had some other issues. But the first thing I’d say is, you don’t have to get up at two or three in the morning to get ahead of the world. If you want to get up at 4:30 or five, you’re kind of pushing it — five is reasonable — but you still have to be in bed for eight hours. If you want to make sure you’re asleep by nine every night and get up at five, go ahead, I don’t see a problem with that. I wouldn’t go a whole lot earlier than that, because circadian entrainment can only go so far — you can’t push yourself consistently out of phase with the sun for too long. I get up around 5:30 regularly, and the world’s still really quiet, plenty of time to get myself going.

To your point — when I first started working with the SEALs, the most common story once I started questioning them about sleep — “why are you taking Ambien?” — was, “well, I have a hard time falling asleep, or I fall asleep fine but I wake up at four and can’t go back to sleep, so I think, I’ll just go to the gym, work out really hard, skip naps, push through my day, and when I come home tonight I’ll be really tired and it’ll be easy to fall asleep.” And then, of course, it isn’t easy to fall asleep, or if it is, they still wake up at 4am the next day. I’d say, “how long have you been trying that — four years?” “Well, keep going, tonight’s probably the night.” You have to educate people that this early waking is what we call terminal insomnia — a symptom of elevated stress hormones. You use stress hormones to compensate for not getting enough sleep, and when you don’t get enough sleep, your basal stress hormone levels are higher during the day, and at some point it gets harder to fall asleep at night because those stress hormones are so high.

Dr. Kirk Parsley

Unfortunately, in men primarily (it can happen to women too, but primarily men, and especially athletic men) — athletic men carry more muscle mass than non-athletic men, and men in general carry a lot more muscle mass than women. So if I get after it all day, I’ll build up adenosine — the final breakdown product of ATP. As adenosine builds up in the brain, it causes sleep pressure, which has nothing to do with normal circadian rhythms — this is what builds up when you stay awake 24 or 48 hours. If you’ve ever been awake 48 hours, you could lay down on a gravel road in the sun at noon and fall asleep, because sleep pressure is so high.

We have roughly the same size head and brain as a woman, but 30-50% more muscle mass, so we produce a lot more adenosine, create a lot more sleep pressure — and usually men can get in bed and fall asleep right away even when their stress hormones are too high. What happens is, after the brain has cleared the adenosine, they wake back up and can’t go back to sleep. Women, by and large, have what we call initiation insomnia — they lay in bed and worry about things they might have done wrong or could do wrong, and have a hard time falling asleep in the first place. Either way, it takes roughly eight hours to recover, no matter when you do it — though if you work out really hard, way outside your norm, you probably need more. It’s not static, you don’t need exactly the same minutes every night, but it’s roughly eight hours. So if you have terminal insomnia or initiation insomnia and you’re chronically getting poor sleep, you’re running higher and higher stress hormones, and at some point those stress hormones either make it hard to fall asleep or wake you up — but you can’t sleep because your stress hormones are high, and your stress hormones are high because you can’t sleep well. That becomes a self-propagating downward spiral, and that’s when you really have to work on getting people to de-stress before they’re ever going to get adequate sleep.

Dr. Kirk Parsley

I could put you in a cold, dark cave with no sense of what time it is — no temperature fluctuations, no light fluctuations — and let you go to sleep and wake up whenever you wanted. After you paid back your sleep debt and adjusted, you’d sleep about eight hours a night, drifting all over the place, but always around eight hours. What would wake you up? There’s no sound, no light, no temperature, nothing. What wakes you up is your stress hormones. That’s normal — as you recover through the night and prepare your body, your brain says, “okay, we’re ready, everything’s in place,” and starts waking you up. Stress hormones are good, they keep you awake in proportion to your environment and will wake you up — but in order to get healthy sleep, whatever level wakes you up, you need to be lower than that when you go to sleep at night.

Bryce Smith

Yeah, I love that explanation, so people can better understand stress hormones. Dr. Kirk, I want to give you some heavy hitters before we wrap things up today, and since we were just talking about stress hormones — I’m going to give you five fun questions to explore, and you’ll have a couple sentences or a minute to answer, so these are some great takeaways for people. What’s a natural cortisol curve for people trying to optimize their sleep?

Dr. Kirk Parsley

A natural cortisol curve — the actual number isn’t something I could give you, there’s a normal sort of range.

Bryce Smith

What does the curve look like, though — higher in the morning?

Dr. Kirk Parsley

There’s not a normal number to wake up to, but there’s a regular one for you when you’re well sleep-adapted, and your cortisol curve will peak about an hour and a half to two hours after you wake up — but it’s getting pretty close to the peak as you wake up. The lowest stress hormones you’ll have in any 24-hour period are the first two to three hours of sleep, during deep sleep — the lowest stress hormones, highest anabolic hormones, lowest catabolic hormones. Over the course of the night, you go from near-zero in deep sleep, doing more and more REM and less and less deep sleep, with cortisol getting progressively higher, until at some point it’s high enough to wake you up. You get a little movement, sunlight, activity, stimulation from the world, a bit higher peak than what actually woke you, and then it declines throughout the day, and by the time you get in bed to sleep, you want it lower than the number that woke you up.

Bryce Smith

Yeah, that’s a great explanation. How does caffeine affect that? We often hear to have hydration before caffeine in the morning to help with the adenosine system you mentioned. What does caffeine implementation look like, and when should people cut it off?

Dr. Kirk Parsley

Caffeine is tricky. It blocks the sleep pressure — again, nothing to do with the rest-and-recovery drive of your circadian rhythm, but your brain’s way of saying “we’re spent, adenosine is high” — caffeine blocks adenosine receptors, so even if adenosine is around, you don’t feel as tired. Caffeine also stimulates your adrenals to produce more stress hormones through neurological processes, and that’s wildly different from person to person — how much caffeine you can tolerate varies enormously. The average half-life of caffeine is about six hours, but it varies from one hour to about thirty. Some people don’t break down caffeine well at all — 100 milligrams stays close to 100 milligrams for hours. Others have an hour-and-a-half half-life, so 200 milligrams drops to 100, then 50, within a couple hours. In general, people who process caffeine quickly don’t have as high an adrenal response as people who process it slowly — which kind of makes sense: a chronically higher level of caffeine in your brain blocks your adenosine receptors and affects your autonomic nervous system, which affects your stress hormones.

Bryce Smith

Would you say noon to 2pm is the window where people should cut off caffeine for the day, at the absolute latest?

Dr. Kirk Parsley

I know really fast metabolizers who have a cup of coffee at 3 or 4pm and it doesn’t seem to impact them going to bed at 10. I know people who, if they drink coffee after 9am, are affected. The generalized rule, going with the average of the population and a six-hour half-life — if you had a 150-milligram cup of coffee at noon, you’d still have 75 milligrams at 6pm, and by bedtime you might be down into the low double digits, which would probably be okay.

Dr. Kirk Parsley

In lectures and worksheets I say, try to cut caffeine off around noon, but there are a lot of exceptions — people who process caffeine faster. It’s an individual thing you can measure with cortisol curves, heart rate monitoring, lots of ways to figure out where you sit on that curve. The easiest way is to taper off caffeine altogether for a while — if you just cut it off you’ll get caffeine headaches — taper to near-zero for a weekend, and experiment with how your heart rate changes after one cup of coffee.

Bryce Smith

The way I create incredible trust with doctors and scientists is based on exactly what you just did — I want to give you a shout-out, because the answer to most questions is “it depends.” It’s easy to give a cliché, specific time, but the reality is people metabolize things differently, and I just wanted to give a quick shout-out that I very much appreciate the long-form nuance, rather than a blind numerical value. It tells me you’re boots on the ground, having these conversations, looking at the research and the data, and I really appreciate that. So — high five and a pat on the back. You mentioned data trackers, and I think they’re awesome for creating habits, and the one you’re most compliant with is the best one. As we continue to explore the best habits for people, what are your thoughts on data trackers?

Dr. Kirk Parsley

I publish something almost every week about not using data trackers as oracles — they’re not the end-all-be-all, they’re useful as a tool to judge trends. You have to understand what about your behaviors or activities has changed, then compare that to the trend you’re going for, because the data tracker is running an algorithm, making assumptions off a couple of variables you’re fitting into it. Something like my readiness score, which I get the most complaints about — your HRV can measure your resting heart rate, but the readiness score has a lot going into it. You might find your sleep score says 70 and you feel phenomenal, or it says 100 and you feel like crap, tired and sluggish. I wouldn’t treat it as “I need to hit 100,” it’s not gospel — we’re not launching space shuttles here, this is biology, it’s messy, there’s variability and nuance to everything. Your heart rate variability over time compared to your activities can be good guidance — hey, when I go to sleep a little earlier, this looks a little better, when I go to sleep a little later, when I spend extra time in bed, when I put my workout at this time, when I cut caffeine off at this time — you have to have some behavior you’re measuring against, then look at whether that trend is going the way you want, associated with changes you think are positive.

The most important thing I always tell people is that how you feel and perform is far more important than what the device says. I have older patients with no interest in technology who do the same thing with a journal — writing down what time they went to sleep, what time they woke up, if anything happened during the night, how they slept, how their day went before bed, their workouts. You can get as detailed as you want with pen and paper too, and use that over time to guide behaviors. But I have patients with tracking devices texting me first thing in the morning — “my readiness score is down, my HRV is 50 instead of a nice level” — and I say, that’s a single data point off a very unreliable device that’s making estimations and running algorithms.

Bryce Smith

Dr. Kirk Parsley, ladies and gentlemen — a deep dive on sleep. Thank you so much for giving us so much amazing and tangible information that we can pay forward to the community. Sleep is probably the number one biohacking tool that most people are missing.

Dr. Kirk Parsley

I agree.

Bryce Smith

Today was super fun. Thank you for your time and your energy, my man. Take care, buddy.

Dr. Kirk Parsley

You’re welcome. Thank you.