Dean Karnazes, for lack of better words, is one gnarly dude. A real gnarly dude. In a good way, of course. An ultramarathoner? What could you possibly be thinking? What makes a man pound the pavement for more time and distance than some people would manage in… How about a decade?

Let’s do some calculations. We’ll use the Fitbit Surge. Say you walk the recommended 10,000 steps per day, seven days per week. That’s 35 miles (assuming that for you,10,000 steps equals five miles). Say you’re not a major runner but you run three miles every other day in addition to hitting that step goal. That’s 6,000 steps. Tack those on to three days of the week for a grand total of 88,000 steps in a week (or 44 miles). Stay with us. Multiple that by 52 weeks and that’s 2,288 miles in a year. Multiple that by 10 and you get 22,880 miles. Karnazes estimates he’s run 100,000 miles in his running career. Right. So he runs a lot.

We flew across the country to run witih him and to find out what exactly does go through his mind, along with 17 other things. Plus, we talked about how he uses the new Fitbit Surge in his training. Here’s what we got on the man of many miles.

MIKE SIMONE: So, how long have you been running?

DEAN KARNAZES: [laughs] My whole life. I started running when I was six-years-old, and then I took a bit of a break in high school, and then starting running again on my 30th birthday.

MS: Tell us a little about that 30th birthday experience.

DK: [laughs] So I was in a bar with my buddies, doing what you do on your thirtieth birthday: Drinking cheap tequila. And at 11 o’clock at night I said “I’m leaving.” They said, “Oh come on, let’s have another round,” and I said, “No, I’m going to run 30 miles right now to celebrate my thirtieth birthday.” So of course they said, “No you’re not running—you’re drunk.” I hadn’t run in 15 years. And I said “I am drunk, but I’m still gonna do it.” So I literally walked out of the bar, I peeled off my pants—I had these silk jockey briefs on—and I just ran off into the night.

MS: What do you love most about the sport of running, and the whole activity behind it?

DK: You know, running is such a simple act, but it’s very dynamic and complex as well. One, I love the freedom of just getting away from things, putting on a pair of shoes and just busting it out. I love the physicality of it. Some of the challenges I take on, like this last weekend I ran a 100-mile foot race in the mountains, just the grittiness of it—it’s kind of a self-confrontation if you will, it’s pushing past your perceived limitations and persevering. And I like that challenge.

MS: And then when did you realize “Oh my god, I’m really good at this, and I can excel?”

DK: [laughs] I don’t know if I’ve really experienced that yet!

MS: That 30th birthday experience?

DK: Thirty miles on my 30th birthday; I thought, you know, big deal, I was drunk. People do weird things when they’re drunk. Much worse things than what I just did. But someone said, “You ran beyond a marathon. That’s insane! Not many people can do that.” And I thought, “Maybe there’s something going on there.” So I went with it.

MS: Do you remember your first pair of running shoes?

DK: When I was in high school I remember using like the Nike waffle iron. Nike came out with the first shoe that had a grid on the bottom. And Bowerman, who was Phil Knight’s partner at the time literally cooked rubber on a waffle iron. And that was what the bottom of the shoe looked like. It was real primitive.

MS: Have you ever thought about calculating how many miles you’ve accrued over the years?

DK: I’ve done back-of-the-napkin kind of stuff. It’s probably over a hundred thousand miles.

MS: What was your favorite part of the 50 marathons in 50 days in 50 states?

DK: That was an insane experience. When I first started that people said, “Oh… do you think you can do it?” I said, “I don’t know, no one’s ever done it before! After five days maybe I’ll be in a body bag.” But I think the most memorable is the 50^th marathon, because it was New York City, which is kind of a tough marathon. I ran it in three hours and thirty seconds.

MS: So you maintained a ridiculous pace.

DK: It was kind of ridiculous on fresh legs, and here I had 49 marathons on my legs, and I thought “Wow. The human body is remarkable.” I think we don’t give it as much credit as I think we should.

MS: How did your body feel after that whole thing? Completely shot, or overtrained?

DK: That was shocking, cause I was in the best shape of my life. I mean it was amazing how good of shape I was in. I was running, averaging like a 3:20 to 3:30 marathon, and my heart rate wasn’t going over 110—literally. I was just clicking out marathons like clockwork. My body really adapted and grew stronger.

MS: What was the most challenging event in your life? Was that it, or was there something else?

DK: [laughs] Oh no, I’ve had much more challenging. […] I would say, there’s this six-day self-supported race I once did across the Atacama desert in South America, which is the driest place on earth. The place we ran—get this—it had never rained. Ever! I’m like, oh in how long? And they’re like, “No. It’s never rained here.”

MS: Wow.

DK: So you had to carry everything on your back for six days, 250-km, all you got at night was a tent. So it was baking hot and then below freezing at night. So you’d be shivering all night long and just roasting all day long. That was probably the toughest.

MS: How do you prevent getting injured with all the running that you do?

DK: [laughs] Knock on wood. Knock on the side of my head! I do a lot of cross training. I think I’ve strengthened by overall body. I don’t just run. So I think cross-training helps. But I’ve never had an injury. Never, ever had an injury. Some of it has to do with biomechanics. My alignment is really true. I don’t pronate or supinate. They say one of the best things you can do as a long-distance runner is to choose your parents well.

MS: [laughs] Lucky, right? So speaking of your training and biomechanics, high-level, what is your training like? I mean, do you go to the gym two days a week and then you run X amount of miles a week? How’s that laid out?

DK: Yeah, so because I travel so much to compete and just for—oh, you know, book signings, all that kind of stuff, I probably average between 70-mile weeks to 200-mile weeks. Then, as far as cross-training, I have a gym set up in my house. So during the day I’m doing these cycles of HIIT, high intensity training with body-weight only. I don’t want to put on a lot of bulk, I just want to get super fit. So it’s sets of pushups—I have this special routine that I developed with a Navy SEAL buddy of mine—pullups, situps, dips, and some burpee kind of stuff. So I cycle through that continually throughout the day, maybe six or seven cycles, so that’s what the average day looks like.

MS: So you have a nice rounded day. So how about food? Are you a paleo guy, any kind of belief system with that?

DK: Well, I’ll start by saying people change. And I certainly change. I’ll never live down the story—one night, I was on a two-hundred-mile run all by myself, in the middle of the night, stranded in the middle of nowhere. I had a cellphone and a credit card. So I ordered a pizza!

MS: Makes sense.

DK: I thought so too! So I used to pound the junk food. Just thinking,  you know, calories were good. But over the course of time, I’ve gone really to a super pure diet. So, complete paleo. Primarily raw. I don’t really cook or process anything I eat, even the meat. I eat raw salmon (I live in San Francisco, so we have a good supply of fresh, sushi grade salmon), and I eat buffalo meat—free-range buffalo meat, lightly cooked, almost like tartare. So I don’t cook much of anything and that’s kind of the way I’ve gone.

MS: So what do you think about while you’re running? I mean I know you think about that pizza, but for the most part when you’re on these long runs, what’s going on in your mind? Are you thinking about the body, or something that’s inspiring you—what is that?

DK: Well, when you’re out on these long training runs, you think about a lot of different things, because your mind’s kind of free to wander. Which I like. I also listen to audio-books. I probably have 500 audio-books on my playlist. But then when you’re racing, like this 100-mile race I just did, you’re running for over 30 hours straight without stop[ping], and you’re so focused on one thing. And that’s crossing the finish line. Nothing else crosses your mind. It’s almost a zen-like state. You’re listening to your body, trying to take in hydration, calculating what your pace is like, trying to foretell your needs coming up, so you’re really focused on one thing. And I really like that, because let’s face it, how often are you focused on one thing for that amount of time? I mean never! At least, I’m not.

MS: Yeah, that’s just crazy, especially when everything is digita l.

DK: Yeah, for thirty hours all I’m thinking about is the finish line.

MS: You’re just in the zone.

DK: Yep

MS: Do you believe there’s overtraining?

DK: You’re asking the wrong guy.

MS: I figured.

DK: I believe in active recovery. So a couple days ago, I just finished running 100 miles, and the last couple days I’ve run. Nothing big, nothing extreme. Kind of like today, maybe five or seven miles. Definitely doing some upper body stuff, trying to flush out the lactic acid. Lots of clear, clean liquid. I think that recovery’s overrated.

MS: How have you seen yourself as an athlete evolve over the years? You didn’t give up on it, but you didn’t run for a few years after high school. How would you say you’ve grown as an athlete?

DK: I think I’ve become more self aware, more aware of my body, more aware of how far I can push before going over the edge. I mean I’ve failed at races. I’ve literally flacked out sometimes. [If you don’t]  push yourself to failure, you don’t know how far you can go.

MS: Right.

DK: So I kind of know where that edge is, I’m pretty in tune with that. I’m also a little more realistic that, as I’m getting older it’s probably going to get harder. I’m still bullheaded, which is a great thing—I’m stubborn as hell. I still think I’m invincible [laughs]. I try to remind myself I’m not. I’ve done so many great races, and I’ve certainly won my share of races and had my share of recognition, so what I’m trying to do now is inspire other athletes.

MS: Right.

DK: I think the greatest gift for a champion is their ability to inspire others to be the best that they can be. So to hell with me! If I can get someone off the couch, if I can inspire someone to try a marathon, that’s more rewarding than winning a race to me these days.

MS: That’s great. If you weren’t a runner, what would you be profession-wise—sport, business, anything besides running. What would it be?

DK: You know I’m a physical guy. So, it would be a physical pursuit. I love mountain biking, I’ve done a lot of adventure racing, obstacle course racing. It would be some kind of high intensity endurance event, just not running.

MS: Let’s talk about the Fitbit Surge. What’s your favorite attribute of the Surge and how does it apply in your training?

DK: To me, the Surge—it’s just a clean device. It’s simple to use, it does everything you need it to do, and it’s just the push of a button. So, no strap to worry about; it’s just simple plug and play, and it does what it needs to do. I also designed the strap myself, because [with] a lot of the GPS watches, the straps suck! So I worked with the Fitbit engineers to make a strap that’s a little more comfortable. You can keep it on for 24 hours and you don’t even feel it.

MS: Great. So finally, you mentioned how you want to inspire athletes. We know you’re going to compete forever; that’s you. But what’s next? What’s the next stage of life as an athlete for you?

DK: So, I’ve been planning, and this has taken a little while to pull off, but I’m planning on running a marathon in every country in the world in one year. So I’m going to set out on a global expedition across 203 countries and I want to run a marathon in each and every one of them. So I’ve been working with the US State Department and the UN, trying to get passports and permits to get into all these countries. I’m working with a company that coordinates the Olympic torch run across the world, so they’re taking care of the logistics. But think about the adventure!