It’s bone-chilling cold outside Indika McCampbell’s Overland Park home — 10 degrees in the late January sun, 5 degrees when the stinging wind slaps McCampbell’s cheeks on her jog down Kessler Road with her dog, Stella.

Honestly, McCampbell, who at 36 is nursing a tweaking hamstring, doesn’t want to jog a single mile today in the bitter cold.

But she also knows that within a week, in early February, she will put her body through the kind of race — a nonstop, 100-mile ultramarathon, lasting upward of 30 hours through day and night — that only a tiny fraction of humans have ever been crazy or daring or driven enough to attempt, no less complete.

Yet, throughout Johnson County, more and more die-hard runners are competing in an expanding number of 100-mile-races (some go even farther) being organized worldwide, from Brazil to Greece, Kansas and Missouri included.

At one race, the Arrowhead 135 held in the woods of northern Minnesota, runners have a time limit of 60 hours to trek 135 miles in the snow inside a state park over snowmobile trails, pulling their food and survival gear in sleds behind them or carrying it on their backs.

Another, the Leadville Trail 100, takes runners up and over trails through the Rocky Mountains, starting at 10,200 feet near Leadville, Colo., and ascending a 50-mile path to 12,620 feet and back down again.

The Badwater Ultramarathon is a sweltering, 135-mile race in 100-plus degree heat that begins in the desert of California’s Death Valley and ascends more than 8,000 feet. In Greece, ultramarathoners run 245 kilometers, more than 150 miles, between Athens and Sparta within 36 hours.

By comparison, the “normal” 100-mile Rocky Raccoon 100 that McCampbell signed up to run in Huntsville, Texas, last Saturday with some 400 other 100-milers might seem tame.

But 100 miles is 100 miles, like running nearly four marathons back-to-back. Plenty of adults can’t drive that far without having to stop.

McCampbell, a first-timer at that distance, has no illusions.

“It’s going to hurt,” she says. “There’s no two ways around that. It. Will. Hurt. … Finishing is the Number 1 goal. Finishing, preferably without crawling.”

Larry Long, 44, of Prairie Village knows what that’s like. A triathlete and psychologist at the University of Kansas, Long last year alone completed more than a dozen ultramarathons, defined as any race exceeding 26.2 miles. Included was the Kettle Moraine 100 that had him running more than 20 hours straight over the mountains and through the woods of the Ice Age Scenic Trail in a state park in southeastern Wisconsin.

Marvin Mastin, 47, also of Prairie Village, has run both the Kettle Moraine and the Rocky Raccoon and is signed up for Colorado’s Leadville this summer.

“There’s nothing else like it,” said Mastin, a contractor. “People do think it’s obsessive and insane.”

Coleen Shaw-Voeks — a 4-foot-11 purple-haired 40-year-old ultramarathoner whose father in Colorado began running 100-mile races as far back as the 1970s — has run nine 100-mile races herself. Now each week at Shawnee Mission Park, she is paid through her business, Tramps Like Us Running, to help train others, including Indika McCampbell, to do the same.

With more than 108 ultra-100-mile races now being run in the United States each year, business is good.

Local trail running clubs, such as the Trail Nerds/Mud Babes in Kansas City and Trailhawks in Lawrence, are expanding.

“I am amazed,” Shaw-Voeks said. “It used to be, in Kansas City, you knew everybody who had done any sort of ultradistance. And now I look at sign-ups for races. Who are all these people? It’s crazy. It’s great. Races are filling up in minutes.”

In Missouri, those races include the Ozark Trail 100 and the Mark Twain 100, run through the woods of the Mark Twain National Forest. In Kansas, there is the Hawk Hundred, which leads runners on four 23-mile laps around Clinton Lake, with eight miles tagged on for good measure. Another race, the Heartland Spirit of the Prairie, is a 100-mile run through the Flint Hills, beginning and ending in Cassoday, Kan.

What these 100-milers know, and what McCampbell, who works as an applications specialist in Lawrence, will soon experience, is that in a 100-mile race, the human body will be stressed and beaten sometimes to the limits of its endurance.

Muscle aches; bone aches; blisters grow so big runners pop them and duct-tape their feet.

“I had a buddy who DNFed (did not finish) because his feet were so destroyed, blisters on blisters on blisters,” Long said. “But you hurt so much your feet are the least of your problems.”

Hallucinations: They’re common, as runners use headlamps and clasp flashlights to trudge deliriously sleepless through the woods or over trails, slumping into 10-minute catnaps at the trailside to gain the strength to go on as the body rebels.

In the late stages of a race, Shaw-Voeks said, “you can get sick and vomit for 50 miles,” as one attempts to balance the intake of sugar and salt and water and eat enough to keep going while burning 10,000 calories and more.

Limbs swell from countless microscopic muscle tears. Days after a race, competitors find themselves urinating to void the fluid.

A sticker adheres to trainer Shaw-Voeks’ car: “Toenails are for Sissies,” a reference to the brutal pounding they take from kicking roots and rocks and the blood blisters that form beneath nails, pressuring them to pop from their beds.

Runners typically bring two pairs of running shoes, with one pair larger than the other. The larger pair is left with crews around the 50-mile mark so runners can slip into them as their feet swell.

“Don’t fool yourself by telling yourself this is healthy,” Shaw-Voeks said. “Forty, 50, 70, 100 miles: It takes a toll. In the end, it’s probably taking years off your life.”

Indeed, last summer, James O’Keefe, a leading cardiovascular researcher at St. Luke’s Hospital Mid-America Heart Institute, sparked heated controversy by saying as much in an article published in June in Mayo Clinic Proceedings.

The article suggested that while moderate routine exercise prolonged life and was good for the heart, “excessive endurance exercise,” like an ultramarathon, was bad for the heart.

“In a word, from a cardiovascular standpoint,” O’Keefe said in a recent interview regarding ultramarathons, “there is nothing good about it.”

“I don’t want to be alarmist,” he continued. “I don’t want to say these guys are at high risk of dropping dead. But if you’re exercising for cardiovascular health, this is not ideal.”

The Copenhagen City Heart Study, which has been following 20,000 Danish adults since 1976, shows that the ideal amount of running is a level that is moderate and routine. Over the years it has compared joggers (1,878) to non-joggers (10,158) and found that joggers had a 44 percent lower risk of mortality for both men and women, adding about six years of life to both sexes on average.

The greatest benefit, however, didn’t go to ultrarunners. It went to moderate joggers (two to three times per week) who put in between 1 to 2.5 hours per week and jogged less than 20 miles total.

Just as significant is the finding that at more than 20 miles per week, the benefits of jogging (at least in terms of the heart and added life) pretty much go away. Their longevity was the same as if they weren’t jogging at all.

O’Keefe said that more recent studies suggest that over the long term, “excessive sustained exercise” like that of ultramarathoners, Ironman distance triathletes, multiple marathoners and even very long-distance bicycle racers, is damaging to the heart’s cells and structure, causing fibrous thickening of the heart’s muscle and stiffening of its vessels.

But as O’Keefe, who is a regular exerciser, concedes, “The people who are doing this are not doing it for their health.”

“We don’t jump out of airplanes or scale Mount Everest or race motorcycles for our health,” he said.

Surely not.

Among these Johnson Countians, the reason is the thrill.

The reason is to wear the coveted Western-style belt buckle awarded to every 100-miler who crosses the finish line.

Each has reasons that are singular and personal. But, as with Larry Long, all say the reason is the challenge.

“The idea of doing this ultrarunning stuff, it serves absolutely no purpose,” Long said. “It is not a healthful task. You can do a lot of other things and be healthy.

“It is, for me, the challenge of being able to do that distance even in those moments when you feel hopeless and doomed. It’s not true, but in my mind, anyone can do a 10K, or a half-marathon, or maybe even a marathon. But doing 50 miles, or a 100K, or 100 miles? For me, it’s the risk of doing something beyond myself.”

For Marvin Mastin of Prairie Village, it’s that, but also a connection to his youth and a reconnection to his father.

Every Friday, Mastin has a routine. He wakes. Then before the sun is up, he heads to a bagel shop not far from his home to meet friends and run “an easy six or seven” miles through the streets of Prairie Village.

Afterward, he visits his construction crews, making sure they’re ready at their job sites. He then drives his pickup truck to Kansas City and to Swope Park and trudges through the woods and up along the limestone bluffs.

“The mountain biking community has done a great job establishing trails out here,” he said as he and a buddy, Tim Keel, 44, take off running several more miles over rocks and roots and ducking branches.

“It’s beautiful, right?” he says.

Unlike road marathons, virtually all 100-mile ultramarathons are held on trails that wind through deserts or over mountains. It is, in fact, on trails not too fundamentally different from those at Swope Park that 100-mile ultramarathons got their beginning.

As the story goes, it began in 1974 at a horseback riding competition known as the Western States Trail Ride or Tevis Cup in California’s Sierra Nevada.

Even for riders, the event, which begins in Squaw Valley, is a grueling single-day equestrian endurance ride, taking horse and rider up and down some 20,000 feet of rugged terrain.

When, in 1974, rider Gordy Ainsleigh’s horse turned up lame, he opted to run the 100 miles and finished in just under 24 hours. A new race had been born. Other runners soon tried.

The Tevis Cup still exists and so does the Western States Endurance Run, better known as the Western States 100. Awarding of belt buckles at the end of a 100-mile race comes directly from those equestrian roots.

Mastin had been running since the age of 10. In high school, the 1984 Shawnee Mission East graduate briefly ran on the cross-country team, but “never ran varsity, never took it seriously.”

But as a young boy, even as an adult, Mastin saw running as a connection to his dad.

“My dad was in Vietnam,” Mastin recalled. “He got shot down over North Vietnam in 1967. It was 2½ years later that my mother found out he was alive. He came back in ’73 with the big homecoming. I was 8 years old.”

His parents remained together for a while.

“Then,” he said, “they split up.”

Mother and father lived in different states. But his father loved running. On those occasions when Mastin would visit his dad, they ran together — 5Ks, 10Ks and, as he got older, marathons.

“We would run races together,” he said. “I think that kind of fueled the fire for me, to enjoy running. It was that kind of connection with my dad.”

Together they ran the Boston Marathon in 2008. Mastin is fast, completing the Kansas City Marathon in October in not much over 3 hours, about a 7-minute-per-mile pace. His dad was part of his support team on a 50-mile run.

Ultrarunning now, Mastin said, is his “secret addiction” a love affair he jokes about with his wife.

“The joke is, she will walk downstairs at night and I’ll be on the computer secretly looking at 100-mile race sites,” he said. “She’ll say, ‘Are you looking at ultrarunning again!?’ I say, ‘No, I’m looking at porn.’ ”

For all the pain and months of training it takes — slowly working up to the point where full 26.2-mile marathons become common training exercises — Mastin said that in its own way ultrarunning is “calmer” than running marathons.

Much, he said, has to do with the demeanor of the people.

Whereas road racers tend to be an intense and competitive brood, constantly checking their wristwatches for their personal best times, trail runners are often the opposite: easy-going, laid-back and, by necessity, mutually supportive in the struggle to conquer the long road ahead.

“It takes a different mindset and a different strategy,” Mastin said. “After you to get to 50, 60, 70 miles, and then up into the 80s, you’re getting to the bottom of your resources and of your mental and physical capacities.”

That’s when, in the dark or cold or searing heat, you rely on others, he said.

At the 50-mile mark, runners are often allowed “a pacer,” a friend to run alongside them to keep them going.

“There is a survival aspect to the whole thing,” Larry Long said. “We always stop. We always slow down. We never leave people alone who have never run the course, even if that means we have to kick it down for ourselves.

“When you see someone death-marching, exhausted, you say, ‘Do you need anything? Do you want me to say anything at the aid station? Do you want me to stay with you?’ It’s endemic in the culture.”

Long is complimentary of his fellow ultramarathoners. He calls Mastin and Shaw-Voeks running “beasts, putting in monster miles.”

He should know.

At 6-foot-4 and 205 pounds, he is a former Kansas high school state champion swimmer from Shawnee Mission East, a college swimmer and an Ironman triathlete. Every morning at 4:40 a.m. Long runs as many as nine miles on the days he’s not running the four miles to Roeland Park to swim 4,400 meters, more than 2½ miles, with the Kansas City Blazers.

That’s before he, literally, puts on his sneakers again and dashes four miles to work as a psychologist at KU Medical Center.

At lunch, he often runs again — two miles or more. His diet is set: nuts, fruit, peanut butter, liquid protein drinks he keeps in one cupboard above his desk.

After work, he tucks his dress shoes inside a second cupboard, neatly folds his suit and tie into his backpack, plugs in ear buds blasting the likes of the Foo Fighters and Soundgarden and runs five more miles home to this family.

Yes, he said, for him 100 miles is arduous. But it also possesses a meditative, Zen quality — making it through the woods, lost in concentration.

“When you’re immersed with nature and running for hours and hours,” he said, “you are immersed in the experience. You are not thinking about the bad things in the future or the past. You’re caught up in the moment. And the environment draws you in and forces you to do that. In fact, if you don’t, you fall.”

In marathons, people talk about “hitting the wall,” of physical and mental exhaustion. Then they talk of pushing through, like breaking into an open field, to find new energy in a wave of endorphins and adrenaline.

“The nice thing in 100-mile races,” said trainer Shaw-Voeks, who has completed nine, “is that you hit that wall over and over and over again. You feel like, ‘I want to die.’ Then you eat something, you drink something, and two minutes later, you’re dashing down the hill feeling fantastic.

“It’s a high. It’s a high. It’s the best non-chemical high you can get.”

Shaw-Voeks understands why outsiders to the sport could easily see ultrarunning as obsessive, self-involved and even narcissistic.

Some runners, she said, train to the exclusion of all else. A number of ultrarunners she knows do tend to have addictive personalities — and sometimes, in the past, have had true substance addictions to alcohol or drugs that they have traded for running. Over the years, she has seen affairs break out among runners and marriages strained and even destroyed.

“It can absolutely tear them apart,” she said of relationships. “There are people who get selfish: ‘It’s all about the running. It’s all about me.’ ”

Her own father bordered on obsessive, she said. His ultrarunning began in the 1970s.

“Our whole life revolved around my dad’s running: when we ate, what we ate. We didn’t go on a vacation unless it was to a race,” she said. “I don’t know how my mother survived.”

Shaw-Voeks didn’t want that for herself. She swore against running and went into the music retail business, where she met her husband, Erik, a musician.

The two eventually moved to Merriam, and then to Kansas City, Kan. In the daylight, they work together in Kansas City at the record store, Vinyl Renaissance, on 39th Street.

Then, six years ago, a stray notion hit her brain like a rush of sugar gel.

“We joke that all of a sudden a gene kicked in,” Shaw-Voeks said. “We were driving across Wisconsin and I just wanted to run. I wanted to run a marathon. I wanted to run with my dad.”

Nine 100-milers later — “I wanted to see how far I could go,” she said, “I wanted to see how far I could push myself” — she leads novice runners through their paces at Shawnee Mission Park at least twice a week. They run trails; they build their endurance, running over-and-over again the mile-long hill that is Ogg Road.

Often, Indika McCampbell is with them, training for the Rocky Raccoon 100.

She doesn’t know if she’ll actually finish. But she is used to challenges. A native of Sri Lanka, McCampbell came to the United States on her own to attend college.

“Just me, myself and I,” she said.

Although she was athletic as a child, doing track, the long jump and high jump as a teenager, “I was never really a runner,” she said. “I rarely worked out through college.”

It wasn’t until her boyfriend, and now husband, Trevor, got a job at a fitness center with runners as clients that she thought of giving it a whirl. She did a 5K and then a half-marathon before someone mentioned trying trail running.

She did, a short one where people ran with their dogs and stood about chatting and chilling out until the whistle blew.

“The vibe was different,” McCampbell said. “There was something laid-back.”

Not long after, in 2009, she attempted her first trail marathon, while others around her were doing runs of 40 miles and 100K.

“That was point where I figured, if there is a bug, I probably caught it,” McCampbell said. “I was doing a marathon and I was running the shortest distance out there.

“I remember getting in the car and saying to my husband, ‘I think I’m going to try for a 40-miler.’ ”

In April, she did. She had promised her husband that after her Rocky Raccoon she would take a break from training, so that the two of them could spend more time together.

Trevor says he is “definitely supportive.” But he also thinks his wife is insane.

In the end, she didn’t finish the Rocky Raccoon, held last weekend. She’d run 72.2 miles, nearly 24 hours straight, the longest distance she’d ever run, before her body began giving out.

“Got pre-hypothermic and never warmed back up,” she said in a text after the race. She reported having blistered feet, swollen ankles and legs, along with aches and pains.

“Nothing that won’t heal,” she wrote. “Had a great time, despite it all, running on some beautiful trails. Even saw an alligator out there, and had frogs and owls keep me company at night.”

She is done with 100-mile attempts — for this year, she said, until she gets stronger and faster.

“I will try this again,” she said.

To reach Eric Adler call (816) 234-4431 or send email to eadler@kcstar.com