Photographs by Patrick Bolger

It’s seven o’clock in the morning, and Gerry Duffy has been swimming for hours. Lips blue, he reaches the end of the lake, finds his footing on the muddy bottom, and stumbles up out of the water. In the distance, thunder rumbles as the drizzle intensifies into a drenching rain.

Physically, Duffy is beyond exhausted. It’s not just that he’s swum 2.4 miles, or that he now must complete the final two legs of a triathlon: a 116-mile bike ride and a 26.2-mile run. It’s that every day for the last nine days he has done an equal amount, as a competitor in one of the world’s most grueling races, the Deca U.K. Enduroman Triathalon Challenge.

Racing for 14 or 15 hours nonstop each day, he’s become so exhausted that he’s hallucinated that the trees are coming to life and that rats are skating on puddles of water. Struggling from the lake to his bicycle, he wonders if he can go on. Stress fractures in his shins send spasms of pain like knife thrusts. And now, he must endure it all in a driving storm. This could be the worst day of my life, he thinks.

And then he starts to laugh. He realizes: Seventeen of the 20 people who started the race have dropped out, and the other survivors are far behind him. This is the time to show how strong you are, he thinks. He hobbles on.

Duffy, a rangy, chiseled 43-year-old from Ireland, certainly qualifies as one of the most remarkable endurance athletes in the world. In addition to winning the Deca (as he did later that day), he has completed a number of punishing long-distance events, including a perversely torturous undertaking of his own devising in which he raced a marathon in each of Ireland’s 32 counties over the course of 32 consecutive days. Perhaps the most remarkable thing about Duffy, though, is that he used to be just like the rest of us.

At the age of 26 he was a chubby, chain-smoking traveling insurance salesman, 60 pounds overweight, unambitious, and comfortable with life. Then one day he saw a photograph of himself taken as he met his hero, golf champion Seve Ballesteros. The sight of the hefty guy next to the legendary duffer shocked him. “I just felt that I was better than that,” he recalls. “I said to myself, ‘I have to do something about this.’” And so he did.

Starting with small, easy steps, he transformed himself from an ordinary schlub into a man of unparalleled toughness. Is there a lesson here for the rest of us?

Mankind has pondered the mystery of personal toughness since the dawn of civilization. Native American youths endured wrenching ordeals before they were welcomed into the fraternity of braves. Ancient Roman soldiers brutalized one another in mock battles. Modern combat personnel face similar preparation. “Every initial-entry training, in any military in the world, is a toughness-building exercise,” says West Point psychologist Michael Matthews. But the study of human resilience is a fairly recent endeavor. In 1975 the federal government deregulated the telephone business, which at the time was a monopoly held by AT&T and its subsidiaries, including Illinois Bell Telephone (IBT) in Chicago. Realizing that the ensuing changes would provide a historic opportunity to observe the effects of mass stress, Salvatore Maddi, then a professor of psychology at the University of Chicago, began a 12-year project to track the fate of 450 managers at IBT.

When the breakup took place, in 1981, half of the company’s employees were laid off. For the majority of them, the experience was painful. “In the following six years, two-thirds of the sample fell apart in various ways,” Maddi says. “There were heart attacks, strokes, violence in the workplace, divorces, anxiety disorders, depression disorders, and suicides.” But for the rest, getting fired turned out not to be a negative life event at all. “The other third of the sample not only survived, they actually thrived,” Maddi says. “They did better than they had before in performance and health.” Among psychologists, the study became a sensation. Conventional wisdom advises to avoid stress at all costs. Yet clearly, for some people stress was not poison but nourishment. What made them different?

As Maddi studied the psychological makeup of those who had thrived, he developed the concept of “hardiness,” which he describes as “the courage to face the fact that life itself is stressful.” Digging deeper, he traced this capacity to three basic attributes, which he calls the “Three C’s.”

The first “C,” commitment, refers to the tendency to see your task as important enough to merit the full scope of your attention and energy. Commitment means that even when your situation is deteriorating, instead of withdrawing, you stay plugged in to your goal. Take Duffy’s example. Completing 10 consecutive triathlons is such a brutal undertaking that only the most committed athletes would even think of attempting it; yet, 90 percent of those who started the Deca with him dropped out due to injury or fatigue. To cross the finish line, let alone win, requires exceptional devotion to the effort. “I have a phrase that I use a lot,” Duffy says. “It is, It’s when we are at our weakest that we must be at our strongest. It’s when you’re most challenged that you have to draw on all the mental powers that you have.”

The second “C,” control, is the feeling that, whatever happens, you’ll keep trying to have an influence on the outcome, rather than becoming passive and giving up. Numerous experiments have shown that a sensation of being out of control is itself highly stressful. Military psychologists found during World War I that soldiers who were forced to passively endure bombardment with no outlet for useful activity, such as attacking the enemy, were likely to crack under the pressure and become psychological casualties. “When I was 26, I had a passive existence,” Duffy says. “When I took up running, I began leading an active life, and living actively is much more rewarding.”

The third “C,” challenge, is an understanding that life doesn’t have to be free of worries to be pleasurable and fulfilling. Stress is natural and provides an opportunity to grow and develop. The key to mastering this mindset is to develop a sense of confidence in your abilities. Yale psychologist Charles A. Morgan III has studied Navy personnel who undergo SERE training (Survival, Evasion, Resistance, and Escape), an intense course that recreates the terrifying experience of being captured, interrogated, and tortured by the enemy. “The people who respond the best are the ones who feel that whatever happens, it isn’t going to get the best of them,” Morgan says.

Soon after his work identifying the three C’s, Maddi began figuring out how the traits can be trained. Although each of us is born with a disposition toward a certain personality type, there are steps that we can take to mold what we’ve been given. Like a bodybuilder who works out to reshape his physique, we can consciously form the mental habits that will make us psychologically tougher.

Duffy is a case in point. At 26, his only exercise was an occasional game of golf. He ate too much and was addicted to candy. All of that ended once he vowed to get himself back in shape. By creating a set of reasonable goals and sticking to them, he lost 60 pounds. He quit smoking, cut back on his portion sizes, allowed himself only one chocolate bar a week, and started running three times a week. Even more important, he started walking an hour after dinner, every single day.

Duffy was no expert in physiology or weight loss, but his strategy employed sound common sense. He laid out incremental steps for himself that were significant enough to seem worthwhile, but small enough to always feel like they lay within his grasp. “Goals have to be realistic,” he says. “And they have to be specific.” Five years after starting his transformation, he was back to his high school weight, and ready for more challenges. “Because I got very physically fit, I got mentally fit,” he says. “I felt like I could achieve anything I set my mind to.” Emboldened, he quit a well-paying job, went back to school, and then started his own company.

Six months later, his brother invited him to take part in a triathlon. Duffy accepted the challenge and took part as a member of a relay team. He completed only the swimming leg but found himself fascinated. “I was immediately gripped by the endorphins,” he remembers. “I vowed to myself that next year, I’d do the whole lot.” The triathlons paved the way for double-triathlons, then multiple marathons, and so on.

The transformation was so extreme that it eventually carried him beyond what he once would have even been able to conceive. Admits Duffy, “If you had told me even five years ago that I was going to run ten triathlons in ten days, I would have said, ‘That’s impossible.’” Without realizing it, Duffy had taken advantage of some of the major techniques that psychologists have found most effective in allowing people to maximize their hardiness. One is a process that Maddi calls “transformational change.”

Instead of panicking in the face of a crisis, the goal is to see the situation from another perspective. Try to understand the larger context and to identify the benefits that might come along with the bad. “Life rewards you when you move out of your comfort zone,” Duffy says. “If you can push yourself to go beyond your fears, you are empowered.”

Another crucial tool is social support. Human beings are mammals, and mammals are fundamentally social creatures. In a tough situation, we rely on emotional rapport with friends and family members. Oxytocin, the hormone that binds mothers to children and husbands to wives, has been shown to lessen the sensation of pain and fear. One study found that just looking at the photograph of a loved one can reduce the experience of pain.

In preparing for his competitions, Duffy had the support of family and friends, but he found that even strangers could provide crucial comfort. During his first double triathlon, Duffy hit a brick wall in the middle of the night after 17 hours of racing. At a rest area he stopped and got off his bike. He still had 80 or 90 more miles to ride, and after that, two marathons to run back-to-back. He was exhausted and didn’t see how he could go on. Then a woman from one of the other teams put her arm around him. “Listen, I’ve watched you,” she told him. “You’re one of the strongest guys out there. I’ve seen the forecast, and tomorrow is going to be a wonderful day. The sun will come up, you’ll get a burst of energy, and sometime in the afternoon you’re going to achieve your goal.” She was right. Duffy got back on his bike, and at 5 a.m., he was re-charged. “I felt on fire,” he says.

Finally, physical fitness itself can be a powerful component of overall emotional resilience. Lilianne R. Mujica-Parodi, a researcher at Stony Brook University, conducted a study of first-time skydivers and found that those with lower body fat showed smaller surges of the stress hormone cortisol that accompanied their terrifying first plunge. “Cortisol is toxic to your brain, which in turn affects your cognition,” she says. “Individuals with lower body fat produced less cortisol in response to the skydive. As a result, the cortisol didn’t attack the brain as much, so their cognition was not as affected.” Simply put, trimmer bodies mean clearer thinking under pressure.

Being resilient is an admirable quality in itself, but it’s also a psychological attribute that allows our other talents to come to the fore. Studies have found that grit serves as a great predictor of success in general, from the performance of contestants in the National Spelling Bee to the likelihood that a West Point cadet will survive basic training.

The effect is so pervasive that the Army, not normally a touchy-feely institution, has in effect begun training all its personnel in the three C’s. In 2009 it launched a training program called Comprehensive Soldier Fitness that is attempting to reshape the emotional habits of its 1.1 million men and women by teaching them the fundamentals of hardiness psychology. “It’s really a radical, paradigm-shifting thing for the Army,” says Matthews. All signs indicate that it’s working.

Duffy agrees that the toughness he acquired by taking up running now affects every other aspect of his life. “It’s only when I started running that my mind was opened to just what I could achieve,” he says. Without running, he never would have had the mental toughness to start his own business, or to overcome a crippling fear of public speaking. Today, he’s a motivational speaker, making a living doing something that once made him feel “scared beyond belief.”

But for Duffy, the greatest gift that running has given him is simply the pleasure of running itself. His most intense moments of joy, he says, come not when he crosses the finish line, but during the months-long ritual of preparation that precedes each event. “Every morning I go out training,” he says. “That’s what I enjoy the most. I just love it.” In other words, sheer will can give us strength to believe that we can achieve anything, and that positivity can be self-fulfilling.