Ben Greenfield stands out for actually knowing what he’s talking about.
Ben Greenfield stands out for actually knowing what he’s talking about. (Photo: Mardo Männimägi)

Ben Greenfield’s Radical Fitness Strategies

Ben Greenfield stands out for actually knowing what he’s talking about.

In today’s fitness space, self-experimentation is the name of the game. All kinds of people are embracing new technologies and diets in the hope of finding faster strategies for getting in the best possible shape. In this crowd, few are pushing things further than Ben Greenfield. The exercise physiologist and personal trainer has made his mark by exploring the limits of what seems reasonable (Example A: injecting his penis with stem cells) and voicing controversial ideas, including skepticism about standard vaccination practices. In his new book, Boundless: Upgrade Your Brain, Optimize Your Body & Defy Aging, he covers almost anything you might want to know about being the fittest and healthiest you can be. For this episode, Outside editor Chris Keyes speaks with Greenfield about strategies for better sleep, the upsides of cold therapy, the problems with gym workouts, and more.

Podcast Transcript

Editor’s Note: Transcriptions of episodes of the Outside Podcast are created with a mix of speech recognition software and human transcribers, and may contain some grammatical errors or slight deviations from the audio.




Outside Podcast Theme: From Outside Magazine and PRX, this is the Outside Podcast.

Michael Roberts (Narrator): When it comes to health and fitness, everyone is looking for shortcuts.

[Suspenseful music begins]

This has always been true. And it makes sense, because training and eating well and generally taking care of yourself? Well, that requires a lot of effort. Lately, though, the hunt for easier approaches has gotten a lot more intense. There's a growing belief that getting fit is more about hacking your diet or your routine than it is putting in the hard work that really makes a difference. I mean, why workout for an hour if you can just put an infrared light on your desk?

Some of this is Silicon Valley's fault. There's an app for everything, right? And you could argue that some of it is Tim Ferris’ fault. His best-selling books explained all sorts of ways that we can transform our bodies and lives and just four hours. Given this climate, it's no surprise that there are hucksters out there selling all kinds of snake oil. But there are also voices who are worth listening to. Ones that understand the advantages of new technologies, but also recognize the reality of what it takes to be as healthy as you can be. This includes the author and exercise physiologist Ben Greenfield. I asked Outside's editor, Chris Keyes, who has been following fitness trends for two decades, for his take on Greenfield. We recently interviewed for the second time.

[Music stops]

Chris Keyes: I guess the most honest answer is Ben is somebody that I... the type of guy that I usually don't like.

[Music re-enters]

‘Cause he sort of has everything figured out. Uh, and he seems to live a perfect lifestyle. Um, he eats right. He exercises right. He sleeps perfectly well. He does everything. And if you read the bio on his website, it's, like, an unending list of successes that speak to a guy who's never really struggled with anything. So, you know, for somebody like me who has a lot of flaws, it's kind of a turnoff.

Roberts: Greenfield has made a name for himself for some of his more questionable endeavors and ideas. A couple of years ago he injected his penis with STEM cells as part of the quest to explore the outer edges of sexual performance enhancement. He's voiced skepticism about standard vaccination practices. Still, Chris says that Greenfield always does his homework.

Keyes: He's somebody in the fitness and health space who really knows what he's talking about. He's been a personal trainer since the early 2000’s. He was once named America's Personal Trainer of the Year, and he, like many others in this space, tested everything on his clients, but also first on himself. And he reads, um, scientific literature relentlessly. So he really knows what's going on, and is just sort of backed up by science. Whatever he's prescribing.

Roberts: Greenfield's new book is boundless. Upgrade your brain, optimize your body, and defy aging. It covers, well, pretty much anything you might want to know about being the fittest, smartest and healthiest human that you can be.

Keyes: ...And I think this book, uniquely to anything else he's written, is literally everything he's learned. It's an encyclopedia. It's 600 pages, probably weighs three and a half pounds. It's a big, big hardcover book that you could use as a weight in your office if you need to get exercise during the day.

And um, I was sort of overwhelmed when it showed up in my inbox. But the cool thing about it is that you can, you can really open up to any page and just dive in.

Roberts: What were the sections that stood out to you personally where you were like, I gotta read this?

Keyes: Sleep. I went right to sleep. I mean, I've got three kids, as you know, and… the youngest is now sleeping well, so we’re back in the good phase, but sometimes it doesn't matter. Kids don't matter. It's all the other parts of life, stress, that you deal with that make it hard to get a good night's sleep. And it's something I'm always wrestling with. But Ben has a chapter on sleep that is just full of good nuggets of information. Um, it's a little overwhelming.

I mean, he starts with a list of—I'm not kidding you—12 tools that he uses. These are products that he uses. I mean, my bedtime routine is one tool. It's a toothbrush. But I was pretty enticed by a few of the things, particularly about napping. Um, I really liked the idea of taking a midday nap. What I'm trying to figure out right now is how I can pull this off in the office without anybody knowing it. I'm fortunate to have a blind that goes on the window into my office. Um, so, it's a matter of what I can set up. Is it a yoga pad? Or something that I can just quick—quickly—discreetly pop in for a nap for 20 to 30 minutes.

Roberts: Yeah. Well, maybe you have to call Ben back and ask him about that.

Keyes: No... I did ask him.

Roberts: Chris reached Ben at his home in Spokane, Washington.

[Music stops] 

Keyes: Another theme that you hit on all the time in this book is the importance of sleep. And I think everybody—especially in this country, where we have a dysfunctional relationship with sleep—has had this drilled into us. Why it's so important. But I'm sure you still have clients to this day who are resistant to it. So what's the, what's the main sell for why sleep is so foundationally important?

Ben Greenfield: Well, I mean, you know, sleep is when your nervous system repairs. It's when learning and memory consolidation occurs. Which is especially important for students, but also anyone who is learning for their job, or needs to learn for their job. It's when this newer concept called glymphatic drainage occurs, which is when the brain actually drains a lot of toxins, a lot of inflammation, and, you know, almost like lymph fluid circulation for the brain. Uh, and you know, when it comes to sleep, I think a lot of people now are pretty aware of basic sleep hygiene concepts, but it's the application of those concepts that becomes important.

So what I mean by basic sleep hygiene is we know that light is important, temperature is important. and noise is important. Really, those are the big three. It would be light, a temperature and noise. And people think: Oh, okay, I'll sleep in a dark room, I'll keep things kinda cool, and, uh, try to make things a little bit quiet in the bedroom.

But there's so much more that you can delve into to optimize sleep. For example, your circadian rhythm doesn't start at night. It starts in the morning by getting exposure to as much natural blue light, as much sunlight as… even looking at computer screens, and phones, all those are forms of blue light as well, which we would find in sunlight. Doing that earlier in the day can actually help to jumpstart the circadian rhythm. And in the book, I even talk about some of these biohacks you can use now, such as uh, bright white light therapy via earbuds that you place in your ears. Or these, these reddish... these bluish-green light producing glasses that you can wear that actually stimulate your retina with a light that simulates what you’d be getting from sunlight, which is, you know... it's useful if you're in an office that's poorly lit, but you still need to jumpstart that circadian rhythm early in the day.

And if you do that early in the day, and then you pair that with light mitigation strategies later on at night, that's really how you manage sleep. And by light mitigation strategies, what I mean by that is you install a software programs such as Iris on your computer, which sucks all the blue light out of the computer screen whenever the sun happens to be setting in whatever area of the world that you happen to be in. Or, you know, as I've done in my bedroom, and in my children's bedroom, you replace the large blue light producing LED-type lights, or fluorescent lights, with red incandescent lighting, which is much more similar to what you'd get from a sunset at night, or a torch, or a fire light. You know, that our ancestors would have used to light things up at night.

And so it's far kinder to the circadian rhythm when you're in your bedroom getting ready for bed at night and there's no circadian disrupting blue light there, you're getting exposed to. You know, another example would be, uh, the temperature. You might be turning the temperature down in your bedroom, which can vastly improve sleep. But there are other cool little strategies that you can utilize such as, uh...  there are companies now, like Chili Pad, that sell these little sheet devices that will circulate 55 degree cold water under your body while you're sleeping. Which I've found to be absolutely amazing for increasing deep sleep cycles. Or you can use a less expensive tactic such as wearing a pair of wool socks when you go to bed, which you would think would keep you warm. But what that does is it causes vasodilation, which actually cools the rest of the body and allows for more blood to be delivered to the core to keep you cool at night.

So there are these little things that you can do to optimize temperature. And then when it comes to silence: Sure. Sleeping in a silent room is good. But you can also do things like download an app onto your phone that will play noise that blocks ambient noise. Like for example, at Stanford university, they've done studies on, you know, white noise, and brown noise. and pink noise, and all these different forms of noise that help to cover up ambient sound. And it turns out that a form of noise called pink noise is the best noise to play. If you were going to put your phone in airplane mode or you know, put on a good set of noise blocking headphones and play beats while you're sleeping or napping. So you know, there's an app that I use for this called Sleep Stream, which is a very simple app. It's like a DJ for sleep.

You can play pink noise, you can play some binaural beats, and it's wonderful to lull you to sleep for a nap, or an airplane ride, or even a full night of sleep. So rather than just keeping the room quiet, you can actually introduce sounds that help to enhance that even more. So the trick is to say, okay: what are the basic sleep hygiene concepts, such as a presence of natural light in the morning and absence of that same light in the evening. Presence of cold in the air, and cold on the bed when you're sleeping. Absence of silence or presence of noises that help to enhance sleep. And then begin to weave all these into your sleeping protocol. You can quantify things like sleep cycles or heart rate variability, nervous system, et cetera. Using something like an Aura ring, or a Whoop wristband, or any of these devices that can allow for to you get daily self quantification. And, man. When I introduce a lot of these sleep biohacks so to speak, my sleep scores absolutely far better than when I just, say, you know, crawl into bed at the end of the night and don't pay attention to these basic sleep hygiene principles.

Keyes: What about naps? Do you consider that like an essential thing? Or is it really from person-to-person, and only if you don't sleep well in one particular night? Or do you advocate for that being a habit every day?

Greenfield: I am absolutely infatuated, obsessed, and in love with my own personal napping routine. So I generally... I sleep seven to eight hours a night, but almost every day, squeeze in a 20 to 40 minute nap in the afternoon. And I get into some research in the book that actually shows that the best time to nap is somewhere between about five to eight hours after you've woken, right? So if you're a 6:00 AM riser, you know, your ideal napping time is going to be somewhere between about 11:00 AM and 2:00 PM. And when you insert a nap into the day, especially if you're not sleeping, you know... Let's say a full... A lot of people, they feel very good on seven and a half to nine hours of sleep during a 24 hour cycle. But that doesn't have to all occur during that single sleep time in bed overnight.

You know, you can slap a little bit onto that from a 20 to 40 minute nap. And by using some of the tactics that I talk about in the book, you can simulate a full 90 minute sleep cycle with just a 20 to 40 minute nap. So, for example, two ways that you could do that: there's a form of stimulation called vagal nerve stimulation, where they have these devices that are typically placed over the temporal lobe or over each side of the neck that actually stimulate the parasympathetic nervous system and lull you into this deep sleep state very quickly. There are apps such as New Calm that play audio sounds that do a very similar thing. And there are even more ancient tactics such as one called Yoga Neidra. And you can, you know, you can download Yoga Neidra tracks off of Apple Music, or off of YouTube, and play these for a very quick, you know, 20 to 30 minute tune up that leaves you feeling as though you've had a full 90 minutes sleep cycle.

And so for me, my nap feels like it gives me two full days. One full day of productivity leading up to about 2:00 PM. Then I get my nap in. And then another full day of productivity after that. Versus what I think a lot of people experience, which is working pretty hard until two or three or four o'clock. And then you get that brain fog, that tiredness that sets in, and the last few hours of your work day you might be operating on fumes and maybe a little bit too tired to hit the gym after work, for example. Or be fully present for, let's say, a family dinner or something like that. For me, that's invaluable because I can just operate at such higher productivity.

Keyes: So, another thing. So cold water therapy. Um, it's sort of like sleep. We've all heard a lot about this, especially in recent years, um, even more recently than the sleep phenomenon of people focusing so much on that. Um, I think though that there's probably even more resistance to that than sleep because it's uncomfortable. So what happens to your body in thermogenesis, with cold water exposure, that is so key? That makes it worth the discomfort that you're going to go through for, you know, a small amount of time?

Greenfield: Well, the benefits are, um… there are multitude of benefits. Uh, I've already talked about or mentioned the Vegas nerve. You know, how you could stimulate the vagus nerve to activate the parasympathetic nervous system, the rest-and-digest nervous system, to be able to relax more quickly. But the Vegas nerve is so important because it's, you know, it's one of these originally cranial nerves that snakes throughout the entire body and innovates the gut, uh, a variety of organs. And there's a concept called vagal nerve tone, meaning that if you have high tone of your vagus nerve, you have better interplay between your sympathetic fight-and-flight nervous system and your parasympathetic rest-and-digest nervous system. Meaning that you have the ability to be able to shift in and out of stress very quickly. Because one's goal should not necessarily be to reduce stress at all costs, but to instead be able to amp up stress when you do want to be stressed. Such as right before a workout or at the start line of a 5K. but you also want to be able to very efficiently shift out of sympathetic nervous systems, such as when the workday is done and it's time to go have dinner. Or, you know, emails in the evening are done and it's time to begin to prepare for bed.

And high vagal nerve tone allows you to be able to do that more efficiently. And it turns out that cold water exposure, particularly to the neck, the head and the face, can actually increase vagal nerve tone. And we know that cold exposure can also do things like cause production of nitric oxide, which acts as a vasodilator, almost like Viagra for the entire body. So you get better blood flow to tissues and the muscles. We know that it can cause the conversion of metabolically inactive white adipose tissue to more metabolically active brown fat. And so, you know, the benefits of cold go on and on. It's wonderful for modulating the immune system as well. It may be able to impart some longevity benefits. And I suspect that the recent men's Finnish longevity study that showed that a regular sauna practice four to five times per week could increase lifespan by four to five years while simultaneously decreasing risk for things like Alzheimer's and dementia… One thing that was left out of that was the cold part of things. Because if you go over to Finland, and you go to any of the sauna houses over there, or—let's say the, you know... any of the Finnish sauna societies—you're not just in the sauna. Typically they're in the sauna for, you know, 10 to 20 minutes. And then you're going out of the sauna through the frigid cold air, jumping in something like the Baltic sea, staying in there, treading water for two to five minutes, getting back out, cooling yourself in the ambient cold air right beside the sea, and then going back into the sauna. And so I think the longevity enhancing benefits of cold may actually, you know, and hopefully, eventually be fleshed out in research as well. And so I'm a huge fan of both the heat and the cold.

But as you alluded to, Chris, you know, it can be, um, it can be difficult. It can be teeth-gratingly difficult to actually get used to a cold practice. And so one of the things that I talk about in the book is simply beginning with what’s called hot cold contrast. And this is based on some research that was done in a Ray Cronise’s metabolic laboratory. And he's the guy that Wired magazine, I think way back in 2013, originally did the article on. He was one of the early metabolic cold thermogenesis researchers. And what he proposed was a hot cold contrast shower, which is a five minute shower comprised of 20 seconds of cold to 10 seconds of hot. And you simply cycle through that 10 times for a total of five minutes. And a lot of people like that. It's kind of like entry-level cold thermogenesis. Cause you're combining it with the heat.

And the cool thing about it is that you're also getting the vasodilation, vasoconstriction, right? Blood vessels shrinking and then enlarging based on the interaction between the heat and the cold, similar to what you get if you were fluctuating between the sauna and a cold soak. Or the sauna and a cold shower. And so that's a very good way to get started. But I think eventually for ideal vagal nerve tone—for training the nervous system—folks who really want to tap into the benefits of cold thermogenesis should get to the point where using proper breathwork, stabilizing the nervous system, settling down the sympathetic fight-and-flight nervous system... getting themselves to the point where they can actually just put the water on cold and step right in. Or stand at the edge of a cold river and just wade right in and be able to resist that mammalian dive reflex, that [Greenfield mimics gasping] sharp intake of breath that you'd normally take in.

And instead just be cool as a cucumber. Literally. As you get into this water, or get into some cold, or even get into a cryotherapy chamber, and just be able to control the nervous system. You know, this is the... I think many of us will do something like cold. Or do something like a hard exercise session. And stay too sympathetically stimulated throughout. And because of that, you can almost be cortisolic, or excessively stimulated by these things. But by staying calm during a cold shower, or a cold bath, you can train your Vegas nerve in a very similar way, actually, as another strategy I talk about in the book: Staying calm during hard exercise. You know, there's a wonderful book called the oxygen advantage by author Patrick McCowen. And he goes into how when you train yourself how to engage in controlled nasal breathing, even during hard exercise, you can actually also increase your vagus nerve tone, and increase your control over the sympathetic and parasympathetic components of the nervous system.

So that's another thing that I personally incorporate into my own exercise routine. Unless I absolutely have to—unless I am so short of oxygen that I have to open up the big pipes and breathe through the mouth—I breathe through my nose during my entire exercise session. And the cool thing is you can go do a hard weight training session or an interval session on the treadmill. And by breathing through your nose the entire time, it almost becomes very meditative. And I've also noticed that you feel less hyperactive after the workout. You feel less exhausted after the workout because you've caused your nervous system to stay just slightly more in control by breathing through your nose instead of by breathing through your mouth. And another reason that occurs is because when you breathe through your mouth, it's far easier to engage in shallow chest breathing. And there are barrel receptors in the chest that can cause a cortisol release when you're engaging in the shallow chest breathing. So the deeper diaphragmatic nasal breathing can control a little bit of that cortisol release as well.

Keyes: You also have some really interesting ideas about the gym, and how we've sort of been conditioned to squeeze our workouts into these confined boxes and confined sets of time. And I think that's particularly timely right now, because we're in the middle of January. It's resolution season. Gym memberships are peaking. But you don't really feel like the gym’s not a bad idea, but it's not necessarily the place that you would start. Why is that?

Greenfield: Well, if... I mean, if you look at formal exercise sessions in a gym or health club, that's something that would have been relegated to the realm of the extreme bodybuilder or the, you know, the gladiator, the warrior, the athlete, the folks for whom performance is a pretty important metric. But, you know, A: We shouldn't fool ourselves into thinking that that's necessarily the best way to maintain health. And as a matter of fact, we've seen that folks who exercise, you know, do a formal hard exercise session the beginning or the end of the day, and then have their butts planted in a chair for eight hours a day apart from that, actually don't see a significant decrease in the risk of cardiovascular disease. Because what's called their, their NEAT—their Non-Exercise Activity Thermogenesis—is relatively low aside from that single exercise session.

And if you look at things from an ancestral standpoint, you know, the human body was meant to move, to take many steps per day. To be building fences, and hauling rocks, and lifting heavy things, and occasionally sprinting from a lion, or chasing down pray throughout the day, and not just have one single, you know, full body-destroying exercise session at the beginning or the end of the day. So what I encourage people to do is to hack their environment so that the formal exercise session, beginning or the end of the day, is an option, not a necessity. And what I mean by that is doing things like converting your office to a standing desk with a walking treadmill. You know, I personally walk anywhere from five to seven hours a day while I'm on phone calls, or doing podcasts, or reviewing literature. Another example would be keeping something heavy on the floor of the office, like a kettlebell or a hex bar that you've got loaded up with some weights that you can occasionally stop during the day to lift something heavy. Putting a pull-up bar installed on the door of an office, or the door of a bedroom. So every time you walk under it, you can hang, you can decompress, you can maybe also do some pull-ups, to be able to build strength via that method.

And, you know, in the book, I've got about five to six different routines that you can just kind of have in your back pocket: that you can stop and do as tiny movement snacks throughout the day. And by engaging in this low-level physical activity, with occasional lifts, and occasional during the day, you actually… you're training the body to be engaged in far more ancestral movement patterns than simply getting huge amounts of inflammation and high amounts of muscle damage from doing something extremely hard at the beginning or the end of the day. But then staying sedentary the rest of the day. And don't get me wrong: I think that a formal exercise session is important for people who might be training for a 10K, or a marathon, or a triathlon, or a Spartan race, or an Iron Man. You do have to go to the gym. You do have to formally exercise. All the more so if you're an athlete or professional athlete. But don't fool yourself into thinking that that's the ideal way to stay healthy, or the ideal way to burn calories.

The gym is a place to build performance, and not necessarily a place to build health. It's the things that you do outside of the gym—the low-level physical activity all day long—that makes a much bigger impact in metabolism and cardiovascular risk disease and in health, then that gym session at the beginning or the end of the day. And finally, one other consideration is that, you know, I personally love the gym. I love to exercise. For me it's almost like meditation. It's my happy place. It's a wonderful little bit of catharsis for me. Sometimes it helps to keep me a little bit more stabilized during the day if I've done something, you know, movement-wise formally at the beginning of the day.

But again, don't think that it's a necessity, especially if you've set up your entire day to be able to stay physically active at the office throughout the day.

Keyes: So you, when you were working on this book, let's say you got up one morning, and you want to have a big day of writing. Or a big morning, let's say. How would you break up the time to ensure those little, um, movement snacks, as you called them?

Greenfield: Yeah. For me it's, it's 25 to 30 minutes of work followed by anywhere from two to five minutes of something active, or something where I'm taking a break and moving. And so the, you know, the actual literature on Pomodoro break shows something closer to like a 55 minute cycle on, eight to nine minutes off, is more effective. But for me, 25 to 30 minutes with two to five minutes off works pretty well. And I can keep that going for, you know, five to six hours of deep work over the course of a morning.

And, you know, when I'm stopping, I'm doing things like kettlebell swings, some pull-ups from the pull-up bar in my office. Being on my walking treadmill, but shifting into a little bit of a jog, or a little bit of a sprint, and then back into a walk once I'm done with that. I've got a quarter mile long driveway, so occasionally it's just running down the driveway to check the mail or grab the boxes and running back up. And so, for me, it's having a bunch of kind of movements and things in your back pocket that you can rely upon for those little breaks that you work in during the day. Um, you know, the other thing is that when I was working on the book and still want to work on articles, I found dictation to be pretty effective as well.

So for example, you know, I have a software on my computer called Dragon Dictation, and that allows me to actually speak, with pretty good accuracy, articles or email. Even when I'm doing something like walking on a treadmill. Because it is hard to type and to move the mouse or the track pad around when you're simultaneously walking. In addition to that, I'm a huge fan of a lot of these balance devices, what are called, uh, you know, mats, balance mats, topographical mats, that you can stand on at a standing workstation. There's one called a TOPO mat. There's another one called a Kai Boone, which is more of a balance device. At our Boulder offices for Keon down in Colorado, we actually have a whole fleet of these devices called a fluid stance. And they're almost like one of those balance boards, but they're easy enough to balance on to where they don't drain you cognitively from whatever phone call or other tasks you happen to be working on. But you can use them to kind of rotate the hips and balance just a little bit while you're at work.

So it doesn't have to be a walking treadmill can be a balanced mat, a TOPO mat, a fluid stance or other balance board. But basically, I'm always moving into a different position during the day when I'm working on any project. Because that's the key. Like, if you just convert to a standing workstation, and you're standing for eight hours a day, you're going to experience, you know, varicose veins, and hip tightness, and low back tightness, and a whole host of issues that might be mildly different than what you'd get if you were sitting all day long. But that are still issues. And so the trick is to frequently switch positions: to be able to kneel, to lunge, to walk, to stand, to sit, and to be in a wide variety of different working positions during the day. Not to simply choose one single position and have that be the only position that you're in.

Roberts: We'll be right back.


Keyes: And so, one thing I'm curious about. So you have all these practices, and obviously you're kind of constantly weaving them into your daily routines. I think that one of the biggest struggles people have—and again, speaking of resolution season—this is when people make these commitments to, you know, pick up a new habit like this. Something healthy. But it's really hard for most people to sustain that. And I'm sure that's true of some of the clients you've worked out with over the years. What do you advise people when trying to pick something up like this and, and you know, prevent it from just being something that you do for a week, but actually for a lifetime?

Greenfield: I think beginning small is important. You know, I recently began to use a new meditation app. And it's one of those apps where you have to do five one-minute meditations, before we'll unlock the three-minute meditation, before we'll unlock the five-minute meditation. And after that, before we're unlocked the 10-minute meditation. So it almost forces you into a scenario in which you really can't get overwhelmed by the option to do more. And I think that in many of these other cases, it is a matter of simply choosing one thing. Like, I'm not going to get a standing treadmill desk, or a treadmill and a standing desk, a TOPO mat, a balance board, a pull-up bar, a kettlebell, and a hex bar, all at once and outfit my office with all of that. The first thing I'm going to do is just slap a kettlebell near my cubicle, or on the floor of my office, and just start with that one thing.

Or, you know, the same thing could be said for cold. All I'm going to do is keep up exactly what I'm doing, my nice warm hot shower every single day, but for the last 20 seconds I'm going to start to switch it to cold. Right? You start with the baby steps. And I think, you know, especially in the realm of biohacking and fitness technologies, there's so much that you could do. So much that you could bite off. But I think starting with the foundational principles and starting small is the way to go. Like, for example, people say: Of everything in the book, what should I actually start with? What would be the lowest hanging fruit? And what I usually tell people is let's say you're eating healthy and let's say you have movement practice. The best thing that you can do is start with treating your body as a battery.

Considering the fact that all of the cells in our body operate on electrochemical gradients: a negative charge inside a cell, a positive charge outside the cell, and we know that certain lifestyle practices or exercise practices can help to keep that charge where it's supposed to be and help to optimize specifically the health of the mitochondria because of that. And really it comes down to just six things in my opinion, that are the biggest things, the lowest hanging fruit that everybody should incorporate.

Number one would be light. I already talked about light, but specifically getting out into the sunlight on a daily basis or purchasing any of these devices that can bring the sunlight into your office, or into your home, like a photo biomodulation panel, or an infrared sauna, or something that allows you to biohack with light. Because the photons of lights are one of the ways that we can charge the body in that sense.

The second would be grounding or earthing. Right? Going outside barefoot on a daily basis, or putting a grounding or earthing mat on the floor of your office, or getting some of these shoes with things like copper plugs built into the bottom of them that allow you to stay grounded or earthed while you're outdoors. Even if you're wearing footwear.

The next two would be heat and cold, which I already talked about, right? We know both regular heat practice, in which you're warming the body, and irregular cooling practice in which you're cooling the body, also stabilizes that electrochemical gradient and has a host of the other benefits that I just talked about. And then, finally, good clean water and minerals. Getting a good reverse osmosis or carbon block water filter, for example, and then remineralizing that water with things like salt or trace liquid minerals. That's another excellent way to ensure that your body has the charge—has the ions—that are necessary to be able to carry those charges throughout the body.

So if you were to start with nothing else, it would be light, grounding and earthing, heat, cold water, and minerals. Like, those are the basic foundational principles. You get a good nutrition and a good movement practice on top of that. And you know, you're going to get 80% of the results.

Keyes: So last thing I wanted to ask about was something you actually addressed in the book, which I was happy to come across. And it's actually fairly early on. Because, you know, one of the things for me when I look at some of this self quantification movement, and all the ways which are... We have these incredible tools that we can track ourselves now. But it also can be exhausting. And you pose the question: Does self quantification suck the enjoyment out of sleep and exercise? And I'm curious how you wrestle with that, with all of this stuff that you're incorporating, to make sure that you're just not just fatigued by all the information.

Greenfield: Yeah, it is kind of ironic, isn't it? Like, we can spend so much time trying to extend our lifespan that by the time we've finished those four hours of sauna, and cold, and smoothies, and electral STEM, and, you know, everything else, we're pretty much grasping at straws. Like, we're spending all that time that we could normally be spending with family, with friends, you know, learning how to play the guitar, engage in other hobbies, et cetera, in this relentless pursuit of living a long time. And we simply can let gears literally slip by with a myopic focus on simply extending life. And it's very easy for this to become just incredibly selfish pursuit. How many things can I do to optimize my body and my brain?

And, you know, I think that a big part of this comes down to time management, and to stacking modalities. Like, for example, I know that earthing and grounding is good for me. I know that this photo biomodulation—the use of, let's say, near and far infrared light—is good for me. I know I need exposure to a lot of the natural blue light in the morning. I know a cup of coffee or tea can give me a lot of polyphenols and flavonols that could help to do things like, you know, lower blood brain barrier leakage, or heal neural inflammation. And I know that that's something like, uh, let's say, uh, standing at a desk might be better for me than sitting for a long period of time.

So when I'm reading all my research that I talked about in the morning, I've got a red light panel shining on me. I'm standing on a grounding mat at a standing desk. I'm drinking a cup of coffee and I'm wearing those in-ear light producing devices. And so, when you stack a lot of this stuff, you know, you're simply doing what you'd normally be doing, like reading research in the morning, but you're actually treating your body at the same time that you're doing it. You know, the same thing could be said with exercise, right? I know blood flow restriction is good and swinging the kettlebells is good and being outdoors is good. So I'll put on blood flow restriction bands and open the door of the garage and get out the kettlebell and stack a lot of these things at once. So I think time management is really important. And then also just being careful not to become obsessed with a lot of these things.

An example of that would be that we know that you get better sleep cycles if you finish up a large meal, at least three hours. Kind of like that exercise session that I talked about prior to bedtime. But at the same time we see, you know, cigarette-smoking, gin-chugging grandmas in Sardinia, Italy who are living long lives despite the fact that they're not pulling out all these biohacking stops. And they’re eating late at night, for example. But they're surrounded by family, and friends, and a robust social life, and positive relationships. And so because of that, you know, in the Greenfeld house, we gather as a family, and have these amazing family dinners, with board games, and table topics, and laughter, and gratitude journaling, for a good hour, hour and a half.

[Music re-enters]

But we don't even start that until about eight, because that's how long it takes for everybody to just kind of be done for their day and ready to settle down for that wonderful celebration at the end of the day.

And yeah. I know that that's not ideal for my sleep cycles. But you also have to consider relationships, social life, happiness, et cetera. And so I always think any of these things that can become incredibly selfish, or you know, relentless pursuit of longevity for longevity sake, they're not as important as managing time so y ou have time leftover for other things, like social life and hobbies and relationships. And they're definitely not as important as having love and other people who you love and who love you in your life you can hang out with during the day.

Roberts: That was Ben Greenfield, speaking with outside editor Chris Keyes. Greenfield's new book is Boundless: Upgrade Your Brain, Optimize Your Body, and Defy Aging. His website is


We'll be back next week.

Roberts: Okay. So wait a minute. So you're my boss officially, and uh, I just want to make it clear here. You are endorsing midday naps?

Keyes: I'm 100% endorsing midnight naps.

Roberts: Okay. All right. Well, I certainly know what I'm doing this afternoon right after lunch today. So, uh, thanks for that.

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Outside’s longstanding literary storytelling tradition comes to life in audio with features that will both entertain and inform listeners. We launched in March 2016 with our first series, Science of Survival, and have since expanded our show to offer a range of story formats, including reports from our correspondents in the field and interviews with the biggest figures in sports, adventure, and the outdoors.