Pushing the Limits: Lessons From Ultra-Endurance Athletes

— -- As part of an experiment to test the limits of human physiology, ABC News Medical Unit Managing Editor Dan Childs ran on a treadmill at high intensity on Thursday night until he "hit the wall."

He pushed through the searing lactic acid buildup, pumped his heart to the max, and reached the point where he started calling on carbohydrates rather than fats for energy. Once he reaches that “crossover point” and the carbs are depleted, his body forced him to call it quits.

Pushing the limits of human fitness in a controlled experiment at NYU Langone’s Sports Performance Center in New York City is extreme. But there is a subset of the population who thrives on the pain -- and euphoria -- of stretching their limits even further.

In 2014, more than 76,000 men and women in North America participated in “ultra-marathons,” pounding pavement and summiting mountains as they completed race courses spanning 50, 100, or even 200 miles.

You read that correctly: some ultra-marathons cover 200 miles of terrain. The races -- which many approach more as adventures than competitions -- test participants’ ability to feed, hydrate and motivate themselves, in addition to their stamina and strength.

‘Just Eating Contests at the End of the Day’

“The nutrition aspect of ultra-running is kind of what gets you to the finish line,” said ultra champion Max King, who won the World 100K race in Qatar in 2014. “Your legs will take you there, but it’s really how well you take care of your body during the race.”

Some ultra-marathoners eat every 15 to 20 minutes, but personal routines are highly variable.

“I try to consume 250 to 300 calories an hour,” said Gavin Woody, who came in first place at the 200 mile Big Foot race through Washington’s Cascade Mountains in 2015. “I eat everything from beef jerky to protein to meat and liquid calories. These races are just eating contests at the end of the day.”

Dr. Martin Hoffman, an ultra-runner and physician-researcher at UC Davis, recalls a tough ultra-marathon where he was craving soup with about ten miles to go -- but the hydration station at that landmark was out of soup.

“I made the decision it wasn’t worth waiting for,” he recalled. He rapidly became “so depleted that I was sitting down.” He did make it to the end of the race -- but with a lot of unnecessary suffering, he said.

He certainly learned his lesson from that, and dozens of other marathons. Hoffman ran his first ultra in 1984, and is one of only 134 Americans who have been completing ultras over a span of at least 30 years.

‘Very Hard, Very Wild, It’s Gnarly’

Hoffman is not the only athlete to get hooked on ultras. In his running career, Gavin Woody has traversed the 211-mile John Muir Trail; sped across the Grand Canyon; trekked a 100-miler in Oahu, and tackled a highly technical 200-mile course called the Dragon’s Back spanning the length of Wales in the U.K., among many other races. Next up? A snowy 100-miler in Alaska.

The appeal, for him, is simple.

“Racing is cool. But finding an adventure, especially with good friends, is even cooler,” he said.

Max King echoed that sentiment.

“It is that adventure -- climbing a mountain in the middle of a race, being out there in the wilderness. ... It’s very wild, very hard, it’s gnarly.”

Though it sounds bizarre, ultra-marathoners also describe their sport as relaxing.

“Being outdoors and running has a very laid-back culture. We’re all friends. We genuinely want to see each other do well,” King said.

Ability to Suffer

Though there is a strong global community of ultra-runners, part of the thrill for Woody is seeing if he can go it alone. Things can get pretty intense flying solo. He remembers hallucinating an encounter with “Mrs. Big Foot” during his Big Foot 200 race, and pushing through some pretty severe foot and stomach pain.

Now an executive in Seattle, Woody previously served in the military and was president of the Mountaineers. He has a lot of training in what he calls the “ability to suffer.” But even more valuable, he said, is his ability to smile.

“I sometimes force myself to smile, and I’ll actually feel better -- one smile equals 10,000 chocolate bars,” he estimated. “On every run, I try to just stop and look up at the trees, and I’m just so thankful for being out here.”

Harry Pino, exercise physiologist at NYU Langone’s Sport Performance Center, is a marathoner and coaches Olympians, but marvels at the dedication of runners who go that extra distance.

He explained that one key strategy is toning down the intensity during races. Many ultra-marathoners will run at a 9.5-minute mile or slower, and spend a good portion of the race walking.

“I think humans in general have a very poor memory when it comes to how much pain they actually endure,” Woody said. For him, “most of the fun is in hindsight.”

Who Are the Ultra-Marathoners?

Hoffman is interested in ultra-marathons not only as a participant, but as a scientist. He and other researchers launched a longitudinal cohort study of over 1,200 ultra-marathoners in 2011.

A baseline study found that ultra athletes tend to be male, well-educated, in stable relationships, and on average older than marathoners (median age of 41-42 rather than 36-37).

Another interesting finding -- ultra-marathoners appear to have similar injury rates compared with other distance runners. Part of the explanation may lie in the softer trail surfaces common in ultra courses. They are, however, at risk for some severe dehydration, gastrointestinal distress and blisters during races.

The long-term health implications of ultra-marathon training are still unclear.

“The real meat of this will come in another 5 to 10 years, when we’ve had a long enough period of time to really see what sort of medical issues have cropped up in this population,” Hoffman said.

Hoffman said he does not necessarily anticipate long-term health damage. His findings will be of interest to many, as the number of ultra-marathon participants in North America has approximately doubled in the last five years.

What About Those of Us Who Can Barely Run a Mile?

Another of Hoffman’s studies focused on the acute effect of exercise on three groups: non-exercisers, modest exercisers and ultra-marathoners. All groups showed an improvement in mood state immediately after exercise, but regular and ultra-marathoners showed greater improvement.

So, if thinking about the fact that some people can run 200 miles intimidates you, take comfort: if you start exercising modestly, the reward is likely to increase the more consistently you work out.

According to Max King, everything feels worth it when you hit your “flow” in a race.

“When you hit that ‘flow’ gate, time goes quickly, you flow down the trail,” he said. “Everything really becomes easy, you feel good and really want to be out there.”

If a runner hits a rut, Woody said to hang tough.

“Sometimes you feel great, sometimes you feel terrible,” he said, “But people are capable of more than they think. I really believe that.”