Ex-Navy SEAL and ultramarathoner David Goggins is the toughest man on the planet. His latest challenge: persuading the world to suffer on purpose.

Throughout the day, Featherstone, 36, a firefighter and an avid runner in Calgary, Alberta, ingests YouTube videos and podcast clips of the former Navy SEAL and ultramarathoner, who reminds him to "Stay hard!" And as night falls, and Featherstone crawls back into bed beside his wife, there Goggins remains on the nightstand - inert, gazing blankly into the darkness.

Featherstone acknowledges the reality plainly: "David Goggins is in my head daily."

The sway that Goggins, who is 46, has over his followers - his ability to occupy their thoughts and persuade them to push past their limits - is hard to overstate. Last month, he oversaw the Goggins Challenge, a two-day test of physical fitness that ran March 5-7. Across 90 countries, tens of thousands of weekend warriors ran four miles every four hours, for 48 hours straight. If you weren't a runner, you exercised. If you weren't a gym rat, you just got sweaty. It was free to enter, and if you wanted a T-shirt, you paid $35.

Devin Featherstone did it in full firefighter gear because why not.

While Goggins ended up donating more than $200,000 in profits from the T-shirt sales to charity, for individual people there is still no good reason to do challenges like these. But Goggins regularly inspires such action. Drawing on stories of his difficult past, mixed with expletive-ridden calls to reject creature comforts, he's found a way to become equal parts drill sergeant, life coach, and superhero for his community of nearly 4 million highly engaged Instagram followers.

"It's just really empowering," said Jenny Petersen, a 48-year-old nurse and runner from Lincoln, Nebraska, speaking of Goggins' list of accomplishments. Petersen - a runner and triathlete - was among those who completed the Goggins Challenge. "People are starting to embrace that it's OK if you suffer, and that you're tougher than you think."

After more than a year of both mental and physical anguish wrought by COVID-19, Goggins' calls to embrace discomfort may seem ill-timed. But for the newly converted and die-hards alike, he's offering people more than motivation: an opportunity to reclaim control of their suffering, and practice it on their own terms.

Goggins' fan base is growing fast, and there are promising signs his ability to monetize that interest - through a bestselling memoir, corporate speaking engagements, merchandise, and avenues yet-to-be explored - could carve out a lucrative "business of toughness" over the coming years.

"I discovered a whole nother part of your fucking brain that a lot of people don't even know about," Goggins told Joe Rogan in a 2018 podcast episode. "It's my job now to take these weak people, in the category that I was in, and say, 'Uh-uh. Stop reading the bullshit. Stop listening to the bullshit.' And if my story of success can impact somebody, it is my job, it is my duty, to share the story." (Goggins declined to be interviewed for this article.)

Achievements born from adversity

He was no fleet-footed runner. In the lead-up to the race, Goggins' cardiovascular training included just 20 minutes spent on the elliptical every Sunday. The task ahead of him: Complete 100 laps of the one-mile track before the 24 hours were up.

The race nearly broke Goggins, who describes the hellacious experience in his book and on podcasts as the most painful day of his life. He broke all the small bones in his feet. His kidneys shut down. By the time he got home, having run 101 miles in under 19 hours, he was smeared with blood, urine, and feces, and was unable to walk under his own weight. His wife at the time begged him to go to the hospital.

"She kept talking, shouting, crying, trying to reach me through the haze," Goggins wrote in his 2018 memoir, "Can't Hurt Me: Master Your Mind and Defy the Odds." "And I heard most of what she said, but I knew if we went to the hospital they'd give me pain killers and I didn't want to mask this pain. I'd just accomplished the most amazing feat in my entire life."

As Goggins described it, that race obliterated any sense of physical limits he'd once had.

Two months after the San Diego 1-Day, he ran the Hurt 100, a 100-mile trail race with 24,500 feet of climbing through hills in Hawaii. In 2006, he completed seven more races of 30 miles or more. In 2007, he completed 14 more, including a third-place finish at the Badwater 135, a race longer than five normal marathons that cuts through the sneaker-melting heat of Death Valley. He's completed two dozen more ultras in the 14 years since.

Goggins has also competed in the Ironman World Championship, finishing the 140.6-mile triathlon in 11 hours and 24 minutes. And in 2013, he broke the Guinness World Record for most pullups completed in 24 hours with 4,030. He broke the record with seven hours to spare.

For people such as Petersen and Featherstone, Goggins' core appeal is his mental toughness, which Goggins said he channels into "going the distance," not winning the race. He speaks often of the "40% rule," which says that when people typically give up, they're really only 40% depleted.

"The reason it's so powerful," Goggins wrote in "Can't Hurt Me," "is that if you follow it, you will unlock your mind to new levels of performance and excellence in sports and in life, and your rewards will run far deeper than mere material success."

The San Diego 1-Day marked Goggins' first step on the road to becoming an endurance athlete, but overcoming adversity stretches back to his childhood. Growing up Black in the small, predominantly white town of Brazil, Indiana, he faced virulent racism and struggled with a learning disability, speech impediment, and low self-esteem.

"I damn sure wasn't going to get into college based on academics," Goggins wrote in "Can't Hurt Me." "All I knew was that I had to get the fuck out of Brazil, Indiana." He saw the military as his best chance and took the requisite entrance exam three times. On his third try, he met the minimum standard for the Air Force.

To date, Goggins is the only person to complete training as a Navy SEAL, Army Ranger, and Air Force Tactical Air Controller. And "when that glory faded," about 20 years ago, Goggins set his sights on ultramarathon running, said Brent Gleeson, a former Navy SEAL who graduated from SEAL training with Goggins in 2001.

"He's always striving, as he would say, to recertify himself as a savage," said Gleeson, who is now an entrepreneur and the author of several books, including "Embrace the Suck: The Navy SEAL Way to an Extraordinary Life." "It's that continual journey, and I think that inadvertently started to spark something in other people."

Even in middle age, Goggins seems to have no plans of slowing down. In October, at 45 years old, he ran 238 miles in 62 hours, 21 minutes, and 29 seconds as part of the Moab 240 in Utah. It was good enough for a second-place finish.

Not just transformation - multiplication

But now the 46-year-old veteran is increasingly turning his attention toward brand-building. In 2016, Goggins, along with his team, founded Goggins LLC as a way to start investing in himself, as he told Rogan on his first of two podcast appearances.

"I try to be as real as I can," Goggins said, "because we're all fucking suffering in this world. We're all hurting. And I try to take away all titles you wanna give me to let you know that I did not come from that shit. That's why I have to be so authentic and so real about my own insecurities and my own faults, and being a fucked-up person."

Influencers strive to be as authentic as possible; it can make or break a nascent brand. Fortunately for Goggins, who may never even use the word "influencer," staying true to himself and his story has been the greatest source of his success - and sometimes his stress.

"My biggest fear in life is, people can read right through a motherfucker that's not real," he told Rogan. "I do it all the time. A lot of people have these great quotes, and they mass-produce. I can't mass-produce something, man."

Instead, he's started giving talks. He's spoken at companies such as Cisco and Microsoft and at pro sports teams such as the Seattle Seahawks and the New York Giants. (Because of COVID-19, he has not given a talk since March 2020, a spokesperson confirmed.) Clips from these talks carry titles such as "Stop Talking Yourself Out of Being Great" and "Get Comfortable With Being Uncomfortable."

There is ample room for Goggins to grow in these spaces: Together, the self-improvement and motivational-speaking markets are worth about $15 billion. And they are expected to grow between 4% and 6% over the next few years, according to research from Marketdata Enterprises.

In 2018, he and his co-author, Adam Skolnick, self-published his memoir, "Can't Hurt Me." He said in a 2019 Facebook Live event that, despite being offered an advance of $300,000, he turned it down "at the last minute" and decided instead to invest $800,000 of his own money in self-publishing. (Goggins' press representative did not respond to Insider's request to confirm these figures.)

"It was the best decision, business-wise, I ever made in my entire life," Goggins said in the event, "because I had the mental toughness and also the ability to know what was right for me and my brand."

The book ended up selling 900,000 copies across print and digital within the first four months, Deadline's Patrick Hipes reported. It stayed on The New York Times' bestseller list for 14 weeks and has sold more than 3 million copies to date. According to Bookscan data, roughly 300,000 of those copies are from the two bound editions.

"That's spectacular for any book," said Giles Anderson, the owner and founder of Anderson Literary Agency.

Still, even as a businessman, Goggins is adamant that money isn't what gets him up in the morning. "I'm not driven by the business," he told Rogan. "I'm a minimalist motherfucker. Gimme a backpack, a fucking ground to sleep on, a pullup bar, some fucking running shoes, and a Subway sandwich, and I'm fucking straight."

To be sure, Goggins isn't the only tough-as-nails influencer. Plenty have come before him, Tony Robbins perhaps looming the largest, literally, over the past two decades. Nor is Goggins the only veteran turned life coach to break onto the scene in recent years.

Jocko Willink is a retired naval officer, a podcaster, and the author of several books, including "Extreme Ownership: How Navy SEALs Lead and Win." Willink is well known on Instagram, where he has nearly 2 million followers, for posting gritty, black-and-white close-ups of his digital watch displaying ungodly wake-up times. A recent photo showed the time as 4:25:41. The caption: "WARPATH."

Many of Goggins' followers also find strength in Jocko, as he's better known. But where Jocko has posted more than 4,700 times, Goggins has just 335 posts to his name, and each one is a viral sensation in its own right. His videos regularly pull in more than a million views.

To retired SEAL Gleeson, who previously founded and ran a digital-media agency for 11 years, the growth and engagement Goggins has achieved are nothing short of anomalous. "I've never seen an explosion of rapid growth from a social-media-brand standpoint," Gleeson said. "Never seen it before."

Goggins isn't for everyone … yet

Part of Goggins' appeal has been the mythic quality that's followed him ever since stories began to surface on YouTube about six years ago. In 2015, the entrepreneur Jesse Itzler published "Living With a SEAL: 31 Days Training With the Toughest Man on the Planet." Itzler never used the SEAL's name in the book, but word soon got out that the "toughest man" was in fact David Goggins. More videos emerged; rumors swirled. Have you heard of David Goggins? The man himself began appearing on podcasts, news shows, and social media.

All that organic growth has created a reputation that some find intriguing. For instance, a month after the official Goggins Challenge weekend in March, a handful of New York City-based runners embarked on the challenge to raise money for charity the weekend of April 9. For others, who may be landing on Goggins' Instagram page for the first time, the catalog of running videos, in which our hero yells at the camera for a minute straight, may seem intimidating. But for every Goggins nonbeliever, there is often a friend close by who's ready to dispel the myths and spread the gospel.

Joelle Tomlinson, a morning-news host in Calgary, and a friend of Featherstone, regularly runs ultramarathons. When she came across Goggins, in 2020, by way of a running partner, she first thought, "Wow, this guy is absolutely wild" - in a good way, she said. "I've never heard of anyone like this. I think he has completely made this recreational suffering more achievable." She said she was eager to pick up a copy of his book.

But then there are people such as Jacy Cunningham, a 32-year-old professional trainer in Maryland, who admire Goggins for his intensity but find less value in glorifying it as a way of life. "Our society promotes pure extreme," said Cunningham, who runs his own business on a holistic form of fitness called the Jacy Method. "We're fanatic about crazy shit. We're big on pushing ourselves to crazy limits."

Devin Featherstone said an increasingly comfortable world is to blame. "People are driving more toward that in-your-face attitude of how Goggins tells you straight up: If you're lazy, you're lazy. You're not candy-coating it, and I think more and more people need that."

Still, even a superfan such as Featherstone said he's motivated most by his family and his values, and that he taps the fearless warrior in his head only when times get tough. As a dad to a 5-year-old son, he knows the misery of a 4 a.m. wake-up. But after studying "Can't Hurt Me" and listening to clip after clip, Featherstone said cleaning a mess or settling a dispute doesn't seem so bad.

"There are things that I would bitch and complain about that were really small," he said. Now, not so much, and people have even asked where his inner peace comes from. "I'm, like, 'Honestly? I read David Goggins' book.'"