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RHR: The Benefits of Optimizing Your Sleep, with Dr. Kirk Parsley


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I can’t emphasize it enough: sleep is crucial for your health. Lack of sleep impacts your cognitive function, performance, mood, memory, and much, much more. In this episode of Revolution Health Radio, I talk with sleep optimization expert and former Navy SEAL Dr. Kirk Parsley about the importance of sleep and the effect that optimized rest has on your life and your performance.

Revolution Health Radio podcast, Chris Kresser

In this episode, we discuss:

  • Parsley’s background with the SEALs
  • Factors that improve sleep and the problem with melatonin
  • The impact of getting better sleep
  • Why it’s difficult to prioritize sleep

Show notes:

Hey, everybody, Chris Kresser here. Welcome to another episode of Revolution Health Radio. This week, I’m really excited to welcome Dr. Kirk Parsley as a guest. Dr. Parsley is a former Navy SEAL, a physician for the SEALs, a health and sleep optimization consultant, and a performance enhancement coach for some of the most driven achievers on the planet.

I’ve known Dr. Parsley for several years. He is a wealth of knowledge when it comes to sleep and the impact of sleep on performance. And because of his work with the SEALs and other high-level athletes, he has some real on the ground, nuts-and-bolts wisdom in these areas that I’ve relied on for many years. He’s been a member of the American Academy of Sleep Medicine since 2006, and has served as Naval Special Warfare’s expert on sleep medicine. He’s also certified in hormonal modulation, and continues to consult for multiple corporations and professional athletes and teams.

So I’m really looking forward to this conversation, and I hope you enjoy it. Let’s dive in.

Chris Kresser:  Dr. Kirk Parsley, pleasure to have you on the show.

Kirk Parsley:  Thank you very much, Dr. Chris Kresser.

Chris Kresser:  So, we have talked in the past a lot about sleep and performance, and I thought it’d be good to revisit that. It’s been a while. I had Matt Walker on the show a little while back, who I know you know.

Kirk Parsley:  Oh, that’s right. Yeah.

Chris Kresser:  And he’s a wealth of knowledge when it comes to the research and all the literature on sleep and performance, and just sleep and health in general. But I thought it’d be fun for us to dive into a little bit more nuts-and-bolts, on the ground practical stuff, since you have this incredible experience working with a population of people who are extremely high achievers, like with the SEALs, and then other high-performing athletes and members of the military that you work with.

And so maybe you could just start by telling people, like, how you got into this work and got interested in sleep, and the connection between sleep and performance, and maybe how that evolved in your work with the SEALs.

Dr. Parsley’s Background with the SEALs

Kirk Parsley:  Yeah, sure. So, to fill in the background. So, I was a Navy SEAL right out of high school. Then I got out, and went to college. Went back into the military when I started medical school and went to the military school in Bethesda. And that, anything in the military, any contract pay, you basically pay back with years of your life in that profession. And so, there was an eight-year commitment after that. And I figured I would be able to get back to the SEAL teams and kind of get back to my community.

I was very well-steeped in sports medicine and ortho, and really figured that’s what I was going to do. And I got there really with the intention of doing that. I got there right at a time where they’d just funded an initiative to build our first sports medicine facility and hire our first nutritionist and exercise physiologist, strength and conditioning coaches, and PTs and athletic trainers, and all this stuff. And it was great. Like, I just had this fantastic opportunity to see that sort of niche and the needs of the community fulfilled.

And we brought in ortho rounds and pain rounds and acupuncture, and so, eventually, I became the guy, or at least [the] qualified as sports medicine slash ortho kind of guy, around. And so, in military fashion, they just put me in charge of managing that. Well, now you’re in charge of everybody smarter than you. Like, aw, great. That’ll be perfect.

Chris Kresser:  Trial by fire.

Kirk Parsley:  Yeah, and make sure I’ll tell them what to do. So, what happened was guys would come in my office and being a SEAL is a lot like being a professional athlete in that it is performance based, and there are medical clearances to be able to do it. And if you’re not physically able to do the job, obviously, they won’t let you do the job. But if you aren’t medically cleared to do the job, they won’t let you do the job either. And just, well, a lot more so than with athletes, there are a ton of disqualifying things for SEALs because they may have to be out in austere environments for a prolonged period of time with medical coverage, medical help, true medical help other than just, like, emergency trauma care.

And so, they can’t be on medications that they’re dependent upon. So, just about everything is disqualifying. Blood pressure medicine can be disqualifying. Any type of antidepressant can be disqualifying. There’s just all sorts of things that, if you’re, if they can make the case you’re dependent on that, they aren’t going to allow you, they’re not going to take the risk of having you out there.

Chris Kresser:  So many reasons for these people to be in peak operating condition, so to speak.

Kirk Parsley:  Right, right.

Chris Kresser:  Yeah.

Kirk Parsley:  But, of course, guys do have problems, and then they’re afraid to talk to anybody about their problems. Because if they say the wrong thing, that could be it. They get put on the bench. And so, I had an additional layer of trust built in because I had been a SEAL. I’d been a SEAL recently enough to where there were a lot of SEALs still there that I had been a SEAL with, which matters probably just as much, if not more, because I had a good reputation amongst the guys who knew me as a SEAL. And so, they figured they could trust me, and they came in and started telling me this litany of problems that they had, which you would expect to hear from 45- to 55-year-old burnt-out executives.

Chris Kresser:  Right.

Kirk Parsley:  But you’re hearing it from a 28-year-old Navy SEAL with six-pack abs, right? And they’re complaining about just their motivation and their mood, and lethargy and poor sleep quality, poor sex drive, poor mood control, poor attention, poor cognitive functioning, [and] poor memory. Just a shift in body composition, just despite the fact that they were, and these were guys are the ones who introduced me to Robb Wolf.

Like, I didn’t even know about podcasts and all that stuff. And these guys were, had Robb’s podcasts memorized, and were doing Paleo down to the nth degree. And so, of course, I didn’t have the slightest idea of what was going on with them. And I’m like, this was 2009. I’m like, well, eight years of combat, maybe this is, like, what they called shell shock in past wars, or maybe adrenal fatigue or PTSD, or who knows what. So, being a Western trained guy, I just started looking for answers, actually, with guys like you and Edward Lichten and Mark Gordon, who is really into hormones around TBI [traumatic brain injury], training with the integrative Functional Medicine kind of groups and training with a few people who specialized in adrenal fatigue. And I was trying all of that, and I was doing, like, some IV drips and I got in trouble for that because, apparently, that’s beyond my scope as a doctor to give somebody a Myers cocktail.

So I was told to cease and desist on that. I couldn’t recommend any type of voodoo like acupuncture or, let’s see, rolfing or float chambers or, like, IR [infrared] saunas, I couldn’t recommend any of it. It was all, I was, like, shut down from all of that. But, so, anyway, the one thing that did kind of stand out to me, and I don’t remember how many patients in, but it took a while to stand out to me, was the guy mentioned that he took Ambien every night to go to sleep. And I thought, crap, I wonder what that is. And being a doctor, I’d never had a class on sleep. I didn’t know anything about sleep.

I went to the medical literature, it’s like, somebody can’t sleep, teach them some progressive muscle relaxation, and tell them to engage in some sleep hygiene, like, three basic things. And then, if that doesn’t work, give them Ambien. And if that doesn’t work, give them an antidepressant. And if that doesn’t work, give them, like, a sedative. And if that doesn’t work, give them a hypnotic. And if that doesn’t work, give them an antipsychotic.

Chris Kresser:  Antipsychotic, off-label, yeah.

Kirk Parsley:  Drug them to sleep, right?

Chris Kresser:  Yeah.

Kirk Parsley:  I’m like, okay, all of those are disqualifying. Thanks, thanks for the …

Chris Kresser:  Yeah, not going to help you.

Kirk Parsley:  Thanks for the advice, but that’s not going to work. And yeah, and because I had all of these, because I trained with such a disparate group of non-traditional people, I was just doing an enormous set of bloodwork, which I also got in trouble for because it wasn’t specific enough. But I literally, like, pulled every biomarker I possibly could in those days. And they all had low testosterone, they all had low growth hormone, they all had really low anabolic, pretty much all anabolic behavior was increased, all catabolic was decreased, oxidation was increased, [and] inflammation was increased. All their insulin sensitivity markers for sort of peri-diabetic, even though they’re ripped up and young.

And I, like I said, I didn’t know, but when I started researching what happens during sleep, and why we sleep, and I saw all this hormonal regulation. And I, what I wanted to do, obviously, when I first saw the hormone dysregulation is go, oh, easy, just give everybody hormones, put their hormones back into place, and they’ll be fine. But, as you know, there’s a big cost to that, and the military wouldn’t have let me do it, obviously, anyway, since I couldn’t give IV drips. So, I said, “Well, let’s see what we can do, like, getting people off the sleep drugs.”

And so, I worked with, fortunately, I was working with, obviously, a really great population that were very fastidious. They would take notes, they would come in and talk to me every day, they would report everything. They helped me, kind of, work out a supplementation stack that would allow them to sleep without using Ambien. Then I got them to back off the booze. It didn’t make them not drink, but [I told them] don’t drink yourself to sleep and don’t drink any closer to bed than you have to. And then, I’ll be giving them DHEA [dehydroepiandrosterone] and zinc. And zinc is an aromatase inhibitor, and DHEA is a dedicated pathway for testosterone and addison pregnenolone, and all of a sudden, these guys, all their labs were restoring over the course of about six months, like, all their biomarkers were coming into what you would expect them to look like, and the vast majority of their symptoms were going away.

Now, there was some TBI stuff in there, as well, obviously, and probably some traumatic injury stuff and neurological disorders that have come from blast, and other things like that. So it wasn’t 100 percent, but I did get 100 percent of people off of Ambien who wanted to get off of Ambien, and they all felt, looked, and performed a lot better. And they would, they would allow me to talk to the SEAL teams, to the SEALs, about my findings, in hopes of motivating them to take sleep more seriously, and to get off of sleep drugs and all of that. And I motivated them really through talking about performance and testosterone and growth hormone, because these are things they knew about. This made a lot more sense to them than talking about prefrontal cortex functioning and all that other stuff.

Chris Kresser:  Right.

Kirk Parsley:  So I just honed in on performance. And now, I’m just, like, the sleep performance guy. I’ve not painted with that brush; 10 years later, that’s who I am.

Chris Kresser:  Not a bad guy to be, given that that is an absolutely critical and often underappreciated lever for performance.

Kirk Parsley:  Yeah, yeah.

Chris Kresser:  And now, you’re starting to see articles about the importance of sleep for NFL athletes and NBA athletes. And I think the message is getting out there. It’s interesting. The military is often far ahead in a lot of areas like technology, research, and development because they’re pushing the boundaries of human performance. And so, some of this stuff becomes evident in the military before it’s even evident in the general population.

Kirk Parsley:  Well, it’s a good, it’s a really good research pool. Because you have a generalizable audience, right? Because they’re very self-selected and very similar. So what works for one of them is very, very likely to work for another one of them.

And they’re very dedicated to being the best in the world at what they do, probably to a slightly dysfunctional level. And so, they’re willing to do anything that they recommend, that somebody they trust recommends, and they’re willing to experiment. So, in that respect, it’s a great research population. It’s sort of clinical research. And they’ve come over, and HRC [Human Resources Command] came over to the SEAL teams and validated a lot of what I’d said and did officials, trials with IRBs [institutional review boards] and all this stuff. But the military itself is a really stagnant organization. Really ensconced in tradition and the status quo, [so] it’s really hard to make changes.

So, I mean, I ruffled feathers with doing everything that I did. And now that I’ve left, all the work that I, that I did, well, not all of it, but I’d say 50 percent of it, maybe 70 percent of it, is all gone. And so, people who used to be SEALs and even some guys who still are SEALs, you know, they still reach out to me for help all the time, because they can’t get that. Unfortunately, I know several doctors who treat those guys now, and I get to get in their ears and kind of help still. But the organization itself never, the Navy, the Navy SEALs embraced me, but the Bureau of Medicine [and Surgery] would have had to embrace what I was doing and kind of make policy changes, which is probably never going to happen.

Chris Kresser:  Yeah, I see this in, well, I have a lot of patients who are military or ex-military, and in their interactions with the VA [Veterans Affairs], once they’re out, are pretty horrific.

Kirk Parsley:  Yeah, they are horrific. They’re literally just that.

Chris Kresser:  Yeah.

Kirk Parsley:  Yeah, I have VA access because I’ve been out since 2013. I’ve still never set up an account or, like, went and checked in to become a patient or anything, just because that would be a last, last resort for me. Like, I’d have to be broke, broken, and just on death’s door before, that would have to just, I’d be, like, homeless or something before I’d be seen there.

Chris Kresser:  Which is horrible, right? I mean, these are people who have dedicated their lives to serving the country, and then they can’t get the medical care that they need. That’s really inexcusable that we’re in the situation that we’re in there. So let’s talk a little bit about the work you did with them. I know you did a lot of experimentation in terms of what would work and what wouldn’t work in terms of improving their sleep. What were the things that moved the needle the most?

Lack of sleep can affect your memory and mood, impact your cognitive function, and worsen your performance. Get some practical advice for optimizing your sleep in this episode of RHR. #optimalhealth #wellness #chriskresser

Factors That Improve Sleep and the Problem with Melatonin

Kirk Parsley:  Well, so when I first started doing research, I think Robb was already talking about it. Maybe it came from, and I can’t remember the first source I found on it. But I found some, I don’t know if it’s research or just guidance, opinion, whatever, about vitamin D3’s association with insomnia. And I thought, oh man, that’s obviously it, right? Because my guys work at night and sleep during the day. And if they do get out in the day, they’re always covered from head to toe in camouflage. And I looked through all their labs, and I pulled labs on hundreds of people at this point, and I checked vitamin D3, and they were all low, they were all deficient.

And I’m like, that’s it, man. I’m going to give them all 8,000 IUs of vitamin D3 every day, and I’m the smartest guy ever. I solved it. And it didn’t quite turn out to be some magical elixir, but it was helpful. So, [I] do some more research and I found out about, I found that magnesium was a cofactor for all the vitamin D3 reactions. Okay, so let’s add magnesium. I don’t know if Natural Calm wasn’t out or if I just wasn’t aware of Natural Calm. I think I started with Milk of Magnesia, which is disgusting, but then eventually moved over to Natural Calm, which was slightly less disgusting. And then, of course, the common idea of using melatonin, and we danced around with that a little bit. I didn’t find that to be super helpful; probably of everything, that tended to be the least helpful one.

Chris Kresser:  That’s really interesting, right? Because that’s often the first thing that people think of. So why do you think that is?

Kirk Parsley:  Well, I think that one, the literature out on it was really inadequate at that time, and we were using way too much. So, even if it was enough melatonin to really whack somebody and change their neurophysiology enough to get them really sleepy, it usually went away pretty quickly, and with any sustained use for probably six weeks or something, you’d have such a downregulation of receptors that even though you’re giving them 500 percent or actually probably 500 times the physiological need of their brain, it’s all going in super concentrated, coming out really quickly, downregulating receptors, and it quits working really, really rapidly. And if you back the dosage down, then you might get it to work a little. You might be able to get it to work for a more sustained number of weeks.

But the other thing that I found with it is that, and this is before any control of release, it was much better at initiating sleep than maintaining sleep. And all the SEALs were already pretty good at going asleep. It was staying asleep that was their problem. And I think that that, again, the reason for that is even if you take one milligram, right? I mean, your brain only makes, like, five micrograms from sundown until sun up. So, if you give somebody one milligram, and half of that gets in their brain, it all gets in there in, like, within 30 minutes to an hour, and then it all starts going away. And so, it just doesn’t simulate neurophysiology in the right way. So, and the other thing is you have to remember that all of my guys had multiple TBIs. I mean, they all have hundreds, if not thousands, of TBIs.

And these are, I forget what the distinction, how they determine distinction, but most of these aren’t impact, right? So they’re not, like, it’s not a conduction TBI. It’s not the right word, but there’s a distinction for when it’s coming from a blast wave. It’s still a TBI, but it damages the brain in a slightly different way. But these are the ones they have thousands of. So their reason for not being able to sleep had a lot to do with inflammation of the brain and disruptions in neurophysiology. And so, the key was really not to try to throw, like, one physiological trick in there and say, “hey, let’s dump a bunch of melatonin in there and initiate all the pathways, and then everything will be fine.” It didn’t turn out to be that way because they were deficient in things, so I supported the melatonin production pathway by giving them L-tryptophan and 5-hydroxytryptophan, which are both precursors to melatonin. Those actually, with the help of vitamin D3 and magnesium, become serotonin, and serotonin can become melatonin.

And if you’re really deficient in melatonin, and your brain’s trying to keep shifting the physiological pathways of your brain, you’ll strip out serotonin. And when you strip out serotonin, then you have depressive, [are] most likely to have depressive symptoms. But serotonin is also an alert-promoting neurotransmitter during the day. And so, if you’re low in that, your affect, your mood, your attention, learning, and all that stuff goes down as well. And then, of course, one of the pathways of, sort of, so melatonin, sort of. The way we evolved when the sun went down, this cascade of events happened in your brain, which led to the pineal gland secreting melatonin, and that was sort of the initiation of a bunch of changes in the brain’s physiology.

And when the brain’s physiology changes, you start losing awareness of your environment, which is really kind of the definition of being asleep, is not being awake. It’s actually the best definition. And all it means is that your brain has dissociated from your environment. And so, that’s what we can observe as far as being asleep. And that’s what sleep drugs do. But what you find when you use sleep drugs is that although it dissociates you from your environment, it doesn’t necessarily lead to the normal stages of sleep and the normal sleep architecture that we find when we do polysomnographies, right?

Chris Kresser:  Right.

Kirk Parsley:  And so, one of the things that does happen after the melatonin secretes it, I mean, it really changes probably 300 to 400 different concentrations of neuropeptides and neurohormones, and neuromodulators when you, once melatonin starts. And one of the big things is GABA [gamma-aminobutyric acid]. And GABA is what slows down your neocortex and makes you become less aware of your environment.

So that’s a very long-winded way of saying I put all of that in there. Because it was just the shotgun approach. Like, well, everything I learned I just kept adding, and I just kept adding and I just kept adding. And then right toward the end, so this is over about a four-year period, and right toward the end I’d learned about phosphatidylserine, which decreases cortisol and decreases stress hormones, decreases norepinephrine and epinephrine and prefrontal cortex, and gets rid of that anxiety insomnia, initiation insomnia, which again, for the SEALs, there’s a really clear reason why big, muscular men can fall asleep really easily. So their insomnia is usually after their first sleep cycle.

But I found if I could decrease their stress hormones, then they had a much better chance of sleeping through the night. And if they could get through two sleep cycles, they could almost always sleep through the night.

Chris Kresser:  And what did you see happen with these guys?

Kirk Parsley:  I think, right, maybe the last six months.

The Impact of Getting Better Sleep

Chris Kresser:  Sorry, I think we crossed over there. But let me just ask you, so what did you see happen with these guys as their sleep started to improve? What did they report back?

Kirk Parsley:  Well, actually the first thing, the most common comment I got was usually after about a week to maybe two weeks of getting really good sleep. And these are people who have, they’ve drunk the Kool-Aid. And they’re like, yes, I’m going to make sleep my number one priority. And then, somewhere around a week or two weeks after, and this is still true with my private consulting clients today, the most common comment I get is, like, it’s like somebody turned on the lights. The world just seemed so much brighter. Like, colors are more vivid, [and] everything is much more digestible and understandable. Like, their visual fields don’t seem as scattered and hectic and confusing.

And they noticed that their mood’s back up and their motivation’s back up. I mean, these are dedicated guys. So, like, they’re going to get up in the morning, and they’re going to go work out, and they’re going to crush it, they’re going to work hard in their job. It doesn’t mean that they’re going to feel like doing it, though, right? So they’re kind of grinding through it. And now, all of a sudden, it’s like, “Hey, I’m not grinding anymore. Like, I actually feel like doing this.” And then, they’ll see shifts in their cognitive functioning. Of course, that comes, actually one of the best rewards of getting good sleep is, I mean, your cognitive functioning increases drastically, like, every single day, you get a good night’s sleep. To where you’ll look back after two weeks of good sleep, and look back to how you were thinking two weeks ago, and go “What the hell was I thinking? Like, how is that even me?”

So really, I mean, the most common comment is, it’s like somebody turned on the lights. And then probably a month or two into it, it’s just, like, “I didn’t really realize how much I’d lost myself. And I feel like I’m getting myself back.” And so, this was across the board, and then, of course, I was chasing it with blood markers. And they’re all going up to very age-appropriate sex hormone levels, their inflammation and oxidation was decreasing, their insulin sensitivity markers were all, like, re-regulating, [and] their cholesterol was re-regulating.

Everything just really fixed itself when these guys did this. But you have to keep in mind, these guys were already exercising well and they were already eating well. And they’re serious about their performance. So, if your life’s a mess, and all you do is start sleeping, you’re definitely, it’s definitely the easiest and best lever to pull that’s going to have the effect across most, the most variable ranges in your health span. But it’s not the magical elixir. You still have to do the other components of being a healthy human being.

Chris Kresser:  Yeah. But it’s often, in my experience, one of the things that’s hardest to get people to shift. Like outside of the military, where you don’t have that as high a level of motivation to maintain performance, and you don’t have the restrictions for drugs where people can’t take those medications, because they’ll get kicked out, they’ll lose their job essentially.

Kirk Parsley:  Right.

Chris Kresser:  Most of my patients are pretty, my patients, as I know yours are, they’re way more motivated than even the general population. They have to be to work with us.

Kirk Parsley:  Right.

Chris Kresser:  And yet, it’s much easier for most of them to, like, make changes to their diet, or even change your physical fitness routine, and maybe take supplements and things like that than it is for them to address sleep. And I know you talk about that a lot, too.

Kirk Parsley:  Yeah, I mean, that still blows my mind. I mean, to this day, that’s still the most challenging thing I do with people, which I just don’t understand. I mean, I’m best known for sleep, and most people who, like, I have never advertised or anything. Clients all come to me [by] word of mouth, or they hear me on [a] podcast or see me present or something. And then, like, 90 percent of the time or 80 percent of the time, I’m presenting on sleep.

And so, I’m well-known as this sort of sleep zealot. And even my application process to become a client talks about sleep ad nauseum. It’s like a nine-page application that says sleep 1,000 times in it. And I start working with them, and it’s still the point that they struggle with. It’s still when I get kickback on them. I can tell these people, they have to spend three hours a day learning how to ride a unicycle, and they would do it.

Chris Kresser:  Right.

Kirk Parsley:  If I tell them they need to sleep eight hours a night, they kick back. Like “Whoa, whoa, I don’t have time for that.”

Chris Kresser:  Yeah, I was talking to Matt Walker about this, too. The thing that’s deceptive is time in bed is not time sleeping, right?

Kirk Parsley:  Right.

Chris Kresser:  Nobody has 100 percent sleep efficiency. So, when I tell someone “you’ve got to sleep for eight, seven and a half to eight hours,” and I say, “oh, by the way, that means generally for most people at least eight and a half hours in bed, if not nine,” they look at me like I’m nuts.

Kirk Parsley:  Right.

Chris Kresser:  How am I going to find nine hours to be in bed?

Why It’s Difficult to Prioritize Sleep

Kirk Parsley:  Yeah. And the reality is that for most people, that is difficult. And it’s just because as a society, we have moved, we’ve adjusted our priorities and our schedules. And everybody talks about entrepreneurs, but just all humans are kind of the same way, that they just keep cramming more and more into their life until, trying to find some sort of fullness. And we now have largely, almost, the common sort of family unit now is a two-income household.

Sort of both parents working. And kids don’t just, like, walk to school and then walk home from school now. It’s like everybody drives their kids to school; there’s hardly any busing anymore. All the kids’ extracurricular activities are spread out all over hell’s creation. Everybody’s trying to use their wealth to provide a better life for their kids and give them more opportunities. If they don’t have kids, they’re trying to go find personal growth opportunities or professional growth opportunities for themselves or their romantic relationships. Whatever.

But we just, like, the cadence of which we, for which we live life, what we consider normal is pathological. And it just, it doesn’t give enough time for people to sleep, to get in bed for nine hours a day. Unless people really, and what usually motivates people is that they feel like they’re broken and they’re kind of willing to try anything, right?

Chris Kresser:  Yeah.

Kirk Parsley:  And that’s, so it’s kind of an act of desperation to do the most obvious thing that had it never been removed, you wouldn’t have probably 70 percent of the problems you have.

Chris Kresser:  Yeah, it’s really backwards.

Kirk Parsley:  It’s unfortunate, yeah.

Chris Kresser:  Yeah, and it’s a systemic problem, as you pointed out. Because if you have a two-earner family, let’s say you’ve got a few kids. So everyone’s getting home from work, and you’ve got to get dinner on the table. And then after the kids, you’re putting three kids to bed if they’re young kids. And then, when is the time where you, like, check your email and just do the few personal things that you need to do if you’re in that situation? It’s really, really hard to do it.

Kirk Parsley:  You sound like you speak from experience, Chris.

Chris Kresser:  No, I mean to be honest, like, it’s pretty easy for me. Maybe because we have one kid and I make my own schedule. And we’re not in that situation. But I can definitely empathize with my patients who are in that situation. I know enough people who are that it’s easy to understand. I think for me, too, I’m one of those people that I don’t have the option. Like, I think some people are actually a little bit more resilient and able to persist with sleep deprivation and continue to function. Even though we, as we both know, I think we’ve talked about this before, there’s a measurable objective decline in performance that happens with sleep deprivation. But what happens, it’s interesting, is subjectively, people think they’re performing at the same level. So, it’s super deceptive, right?

Kirk Parsley:  Yeah.

Chris Kresser:  They think they’re doing fine, but they’re not. But for me, it’s not even, like, just subjectively, I know I’m not doing fine. If I start missing a lot of nights of sleep, I just, I can’t do it. So, I’ve been forced into heavy discipline around sleep.

Kirk Parsley:  Yeah. Well, I think I kind of found all this out just soon enough to prevent a major crash in my life. Because I was one of those people that just destroyed my sleep. I mean, I chose two professions that don’t value sleep at all, right? And it’s really just kind of a sign of weakness that you even need sleep. And so, I went from being a SEAL to being a college student trying to get into medical school, and I was working and had a kid while I was still in college. I was applying to medical schools and I was in medical school, and had a couple of kids and [was] trying to study an indigestible amount of information, still trying to work out because I thought it was smart. I should still go work out an hour every morning. So I was getting up at 3:30 to go to the gym to work out so I could be up in the classroom by five and sit in one room and study from five to five every day, and, like, drink a couple of low-protein shakes as my only source of [nutrients], and come home, get the kids’ dinner, play with them a little bit, give them their baths, read them stories, [and] get them to bed, in hopes that I could get to bed by 9:30, which usually didn’t happen. I usually got to bed around 10:30 or 11:00.

So I just crushed myself for a long time. And then, obviously, internship and the residency weren’t a whole lot easier than that. But then, I hit the SEAL teams, and when I started, what’s good for the goose is good for the gander. So I’m like, “Hey, if it works for these guys, let me try it.” And so, I think I saved myself from really crashing. But I can look back at pictures of myself from 10 years ago, and I look older 10 years ago than I look now. I’m definitely more muscular and leaner and more athletic now than I was 10 years ago. But I had a pretty high base. And so, it wasn’t like, anyone would have looked at me and said I looked out of shape or weak, or anything like that. But, for me, it was, like, really premature aging. And that’s the other misnomer, that because the behavior is so common in society, the sequelae and the behavior are so common, and we’re just, we’ve really just kind of trained ourselves through observational bias to say, “Well, that’s just normal aging. That’;s just the way it is.”

And the SEALs, in fact, used to say that to me. When they’d come in my office and they would complain about all their problems, about their memory deficits, and it had taken them five times to leave their house before they could actually get to work because they kept forgetting things and missing turns on the same path they took every day. And then, they would just say, “but you know, maybe I’m just getting old, doc, right?” And I’d be like …

Chris Kresser:  Like, you’re 28.

Kirk Parsley:  Like, you’re 34, dude; it’s over. You might as well go up behind the barn and suck start your cig right now.

Chris Kresser:  Right.

Kirk Parsley:  It’s over, man. Why are you wasting any more time?

Chris Kresser:  Yeah.

Kirk Parsley:  Yeah, so I think that a lot of people just associate, you know, that foggy kind of, I don’t know, incompetence, isn’t the correct word. But just sort of that cognitive decline that isn’t even pathological yet. But I think if you told somebody that, if you describe somebody who is really energetic and hard hitting, and getting after it and doing some amazing things in the world, most people wouldn’t picture a 55-year-old. They would think, “Oh, that’s probably a 35-year-old, right? Maybe a 45-year-old, max.” But it can be. Like, it could be a 55-year-old. It could be a 65-year-old, right?

The health span is what we have the most opportunity with right now. I believe the lifespan, I believe life extension stuff, it will come around to a significant degree. And I know that there are some gains in that. But if you want to look at just sort of the general population of America and what’s available to everybody, without big expenses and tons of research and all that other stuff, improving the health span is, like, how healthy you are during your lifespan is the most approachable challenge. And to me, the first pillar of that, the foundation of that, really it, I think Matt Walker said something like sleep isn’t even a pillar. It’s like, like it’s the foundation that the other pillars stand on, or something like that.

Chris Kresser:  Right.

Kirk Parsley:  And I agree with that completely. I mean, I agree with just about everything he said; he’s a brilliant, brilliant guy. I wish his book would have been out 10 years ago when I first started this path. Like, it took me 10 years to figure out everything he wrote about or then, and of course, I still learn new stuff in there. But yeah.

Chris Kresser:  Yeah.

Kirk Parsley:  Yeah.

Chris Kresser:  Cool. Well, this is super helpful. I mean, I know, for some people, they’re like, “Yeah, yeah tell me something I don’t already know.” But I still do think there are a lot of people who don’t really fully grasp the importance of sleep. So I’m going to keep talking about it.

Kirk Parsley:  Yeah. Yeah.

Chris Kresser:  And I know you are, too, because it’s, eventually, when it does sink in and click, it makes an enormous difference. And it can be the thing that really works when nothing else did. So I appreciate the work you’re doing in that regard.

Kirk Parsley:  Thank you. I mean, I am optimistic about it, even though people, even though people are really reticent to try it. There is the benefit, the one thing that sleep advocacy has going for it is that the differences or the difference in performance and subjective experience of life are so profound, and they’re so immediate, that it’s a really motivating experience to just prioritize sleep.

So, if you can get people over, if you can get over that tipping point, if you can get over that inertia, resistance point, and get them to actually prioritize sleep and try it, very, very, very rarely does anyone just not go, “Wow, this is amazing. I can’t believe I overlooked this.” And you know, that doesn’t mean they won’t fall off the wagon here and there. Whatever. I mean, obviously, like, we all do the same with nutrition, whatever. But things like fitness and nutrition, I find, you’re waiting 30, 60, 90 days to really kind of look in the mirror and say, “Wow, I really look, feel, and perform better” or something. [With] sleep, it’s like a week.

Chris Kresser:  Right.

Kirk Parsley:  And people know, I mean, really one good night’s [sleep]. Well, usually, if you’re really sleep deprived, you’ll probably feel worse after a couple of good nights. But, like, [after] three to four consecutive nights of really good sleep, most people feel amazing. And then, a week to 10 days of really high-quality, quality and duration of sleep, it’s a life changer. And it’s, if you get people my age (a lot of my clients are around my age), they really haven’t had that experience since they were in their 20s. And they, and I hear that all the time, too.

It’s like, “Man, I feel like, I feel like I did [in] my 20s. I wake up, I feel like I slept, then and I wake up and I forgot how energized I felt. I forgot how much my body didn’t hurt. All these sort of things that [have] just grown to be normal, usual, age-associated. People talk about their memories all the time. They’re like, “Man, all of a sudden, I can remember things that I haven’t been able to remember for 10 years. And it’s effortless, and everything’s just coming to me.” And I’m like, “Yeah, man, you’re just getting rid of the inflammation in your brain, things are working better, you’re forming more, [and] you’re rebonding a bunch of neural pathways that you haven’t been using. Circulation to your brain is increasing. It’s all, there’s a lot of good stuff going on there.” And the brain reacts very quickly. It’s evidenced by, like, a stroke, or something, right?

Chris Kresser:  Yeah.

Kirk Parsley:  Like, two minutes with, you need a change, a new change for who you are as a person.

Chris Kresser:  Absolutely. Yeah. Well I’ve been a big fan of the formula, the sleep formula you put together, for a number of years. I take it myself, and I recommend it. It’s the first thing we recommend to patients, because it’s, I like that it’s just got, I like that it’s just got low, low doses of most of the nutrients and just supports the body’s natural physiological pathways rather than [a] hit you over the head with the hammer kind of approach.

Kirk Parsley:  Right.

Chris Kresser:  And I know it’s evolved over time, too, and just has gotten better as you’ve learned more and developed more. So tell people where they can learn more about that.

Kirk Parsley:  Yeah, they can go to my website at, Doc, d-o-c, parsley. Like the herb, p-a-r-s-l-e-y. DocParsley.com. The product is called Sleep Remedy. You can just Google “sleep remedy.” If you go to SleepRemedy.com, that goes to my website, as well. But yeah, I mean, there’s my TED talks, blogs and podcasts, and all that stuff, if people want to go there just to try to get motivated to sleep, go there for that. If you want to try the product out, go there for that, as well.

Chris Kresser:  Yeah. And it’s a nice little powder you mix with some hot water. I think there’s a good, what do we call it, an entrainment effect that happens with that, too, where you just start to associate that flavor with sleep and sleep onset.

Kirk Parsley:  Yeah.

Chris Kresser:  There’s some interesting research about that.

Kirk Parsley:  Yeah. And that was sort of the intention behind it, to create a bit of a ritual around sleep. We all know that; we all remember being children and having children, [and] there’s a prolonged period of getting a kid ready to go to bed. You don’t just pick them up from playing with their toys, and put them in bed and turn the light off, right? But we think for some reason, we can do that as adults, and it’s just not true. We need some sort of wind down process ourselves. So I forget why there’s some sort of legal reason, I think, where they said don’t put boiling water on there, but I like boiling [water in a] tea kettle, and I pour it in a cup, and we have the lavender now, which is kind of like associated with sleep. And I get a lot of trolling kickbacks about how lavender is estrogenic and all this. I’m like, it’s not really lavender, so settle down. It’s lavender flavoring.

Chris Kresser:  Yes, yeah.

Kirk Parsley:  And then, we still have the apple cinnamon. But those, like, you mix that up and dissolve it in water, and you kind of sip it and dim the lights down. And you’re at least giving some thought to going to sleep rather than just hopping in bed, popping some pills, and lying down and going, “Why am I not asleep yet? It’s been five minutes.” And so, that, yeah, that was a big reason for it. But the Whole30 audience and some other folks were anti flavorings and xylitol and, like, whatever. And so, we made some capsules out of it. But I don’t, I mean, it’s not that I would say don’t use them. It’s not that I dislike them. I just don’t think they’re as good of a pathway as the drinks themselves. But you know, if it helps, it helps. Use whatever you’re wanting to use.

Chris Kresser:  Absolutely. All right, Kirk, good to talk to you as always. Thanks for coming on.

Kirk Parsley:  Likewise.

Chris Kresser:  So SleepRemedy.com, DocParsley.com to learn more.

Kirk Parsley:  Yep.

Chris Kresser:  And if you want to try the formula. And we’ll talk to everyone next time. Thanks for listening.

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