Sometime in the past couple of decades, the idea of running a marathon became less crazy.

Since Oprah Winfrey finished the Marine Corps Marathon in 1994, millions of average Joes and Janes have tackled the distance, and now “26.2” shows up routinely on bumper stickers and bucket lists.

But for some people, a 26.2-mile marathon just isn’t long enough. These athletes are turning to ultrarunning, a sport that not long ago was considered the reclusive, funky-smelling cousin of traditional road racing.

About 1,000 of them will line up Nov. 21 in Boonsboro, Md., to run the JFK 50 Mile, the country’s oldest ultramarathon and one of the two largest. (An ultra is anything longer than 26.2 miles; the most common distances are 50 and 100 miles and 50 and 100 kilometers, or 31 and 62 miles.)

No one is saying that a marathon is short or easy, but there are some huge differences — physiological, logistical and psychological — between running far and running really, really far.

How more miles can affect your body

Scroll down to continue.

1 of 12

hallucinations

Hallucinations are part of ultra lore. When you run around the clock, extreme fatigue and strange shadows in the wee hours can sometimes play havoc with your mind. A nap usually fixes the problem.

2 of 12

temporary blurred vision

Temporary blurred vision can happen in longer ultras, probably due to corneal swelling.

3 of 12

insect stings and bites

Insect stings and bites are more common in ultrarunning.

4 of 12

cuts and bruises

Cuts and bruises from falls are common because of the uneven terrain of ultras.

5 of 12

heart problems

Heart problems are rare in long races; running usually makes the heart and circulatory system stronger. But some recent studies indicate that distance runners may be at slightly higher risk for atrial fibrillation, an irregular heartbeat. Other research has shown some temporary cardiac dysfunction after long races, particularly in the least-trained participants.

6 of 12

respiratory ailments

A high rate of respiratory ailments found among ultrarunners in a 2014 study may be largely attributable to dust and flora along trails.

7 of 12

exercise-associated hyponatremia

All distance runners should be aware of the risk of exercise-associated hyponatremia, a potentially deadly condition in which drinking too much water or sports drink dilutes the body’s sodium, causing cells to swell and burst.

8 of 12

hypothermia

Body temperature is more likely to drop too low (hypothermia) in an ultra, when energy stores are depleted and weather conditions vary. Heat illness is more common in marathons, in part because of the more intense effort.

9 of 12

gastrointestinal issues

Marathoners burn a higher percentage of carbs and can get by on sports drink and gels. Ultrarunners burn a higher percentage of fat and usually need real food, which can mean more gastrointestinal problems.

10 of 12

muscle cramps

The longer the race, the more likely muscle cramps will strike, most often in runners’ quadriceps, hamstrings and calves. No one knows exactly why cramps occur, but most research points to fatigue in the mechanisms that govern muscle control and contraction.

11 of 12

stress fractures

Stress fractures and other musculoskeletal overuse injuries can plague long-distance runners. Feet are the most common site of stress fractures in ultrarunners, but fractures of the pelvis, femur, tibia and fibula also occur.

12 of 12

blisters

Blisters are more common in ultras, thanks to mud, water, rocks and dust that can get into shoes and socks. Also, moving on varied terrain, such as steep downhills, can cause friction spots.

Hallucinations are part of ultra lore. When you run around the clock, extreme fatigue and strange shadows in the wee hours can sometimes play havoc with your mind. A nap usually fixes the problem.

Temporary blurred vision can happen in longer ultras, probably due to corneal swelling.

Insect stings and bites are more common in ultrarunning.

Cuts and bruises from falls are common because of the uneven terrain of ultras.

Heart problems are rare in long races; running usually makes the heart and circulatory system stronger. But some recent studies indicate that distance runners may be at slightly higher risk for atrial fibrillation, an irregular heartbeat. Other research has shown some temporary cardiac dysfunction after long races, particularly in the least-trained participants.

A high rate of respiratory ailments found among ultrarunners in a 2014 study may be largely attributable to dust and flora along trails.

All distance runners should be aware of the risk of exercise-associated hyponatremia, a potentially deadly condition in which drinking too much water or sports drink dilutes the body’s sodium, causing cells to swell and burst.

Body temperature is more likely to drop too low (hypothermia) in an ultra, when energy stores are depleted and weather conditions vary. Heat illness is more common in marathons, in part because of the more intense effort.

Marathoners burn a higher percentage of carbs and can get by on sports drink and gels. Ultrarunners burn a higher percentage of fat and usually need real food, which can mean more gastrointestinal problems.

The longer the race, the more likely muscle cramps will strike, most often in runners’ quadriceps, hamstrings and calves. No one knows exactly why cramps occur, but most research points to fatigue in the mechanisms that govern muscle control and contraction.

Stress fractures and other musculoskeletal overuse injuries can plague long-distance runners. Feet are the most common site of stress fractures in ultrarunners, but fractures of the pelvis, femur, tibia and fibula also occur.

Blisters are more common in ultras, thanks to mud, water, rocks and dust that can get into shoes and socks. Also, moving on varied terrain, such as steep downhills, can cause friction spots.

In contrast to big-city marathons, U.S. ultramarathons tend to be spartan, low-key affairs, often beginning in very small towns near very long trails. JFK, for instance, is run mostly on the Appalachian Trail and the C&O Canal Towpath.

[An insider’s tour of the JFK 50 mile course]

Marathons

Both sports

are growing

550,637

U.S. finishes, in thousands (not finishers — some people run more than one a year.)

500

400

300

200

Ultras

100

76,500

0

1980

2000

2014

* The 2012 New York City Marathon, which usually has about 45,000 finishers, was canceled after Hurricane Sandy.

Sources: USA Running, UltraRunning Magazine

RICHARD JOHNSON/THE WASHINGTON POST

Many ultramarathons have fewer than 100 runners and almost no spectators.

“You’re surrounded by nature,” said Amy Pope Fitzgerald of Chantilly, who has run both Marine Corps and JFK each year since 2012 and has completed one 100-miler. “I like the fact that ultras are smaller, and you’re just running, so you make friends. I’m not having to fight for my spot on the course.”

Not yet, anyway.

The closest thing ultrarunning has had to an Oprah moment was the 2009 publication of Christopher McDougall’s “Born to Run: A Hidden Tribe, Superathletes, and the Greatest Race the World Has Never Seen,” a bestseller that introduced many readers to the world of ultras. U.S. participation has more than doubled since then.

More than two-thirds of those participants are men, according to UltraRunning Magazine, and more than half are older than 40.

Longer distances seem to attract older runners who can compensate for lost speed with greater perspective and experience — not to mention perseverance.

Most people finish a marathon in three to six hours and make it home in time for lunch. But a 50-miler takes an average of 10 hours, said Karl Hoagland, publisher of UltraRunning Magazine, and 100-milers typically take 24 to 30 hours or more of nonstop forward motion.

“As you get older, you realize the sun’s going to come up, and you get less rattled,” said Mike Joyner, a distance runner and a Mayo Clinic physiologist who studies how human bodies respond to exercise.

Men outnumber women

MARATHON FINISHES

IN 2014

Women

 

 

Men

 

239,271

311,366

43%

57%

ULTRA FINISHES

IN 2014

Women

 

 

Men

 

24,327

 

52,173

 

32%

68%

Sources: USA Running, UltraRunning Magazine

RICHARD JOHNSON/THE WASHINGTON POST

Not long after runners cross the start line, other factors unique to ultramarathons appear.

In marathons with huge fields and prize purses to match, the top runners fly off the start line and maintain a pace of less than five minutes per mile until they finish a little more than two hours later.

Top ultrarunners also start fast, but courses and human physiology don’t permit them to maintain a constant breakneck pace for hours on end. Even the fastest competitors hike rather than run at times.

“Everything has to be adjusted. You’d crash too soon if you run at marathon pace,” said Jim Hage of Kensington, who won Marine Corps in 1988 and 1989, then won JFK in 2002 at age 44. “You have to take everything a little bit easier . . . and if you get in trouble at 20 miles? Wow, that’s a long way home.”

[Mental mileposts on the super-long-distance run]

The lower intensity is measurable. Marathoners’ hearts often beat at 75 to 85 percent of their maximum heart rate for the duration of the race, Joyner said. That’s not a sprint, but it is a moderately hard effort.

Ultrarunners, he said, spend a lot of time at 50 to 65 percent of their maximum heart rate, with elites on the higher end and the just-happy-to-finish folks at the lower end.

This is probably a main reason heart problems show up less often during ultras than in marathons, according to Martin Hoffman, who has studied the medical side of ultrarunning as research director for the Western States 100-Mile Endurance Run. Western States is to ultrarunners what the Boston Marathon is to marathoners: a showcase for top racers with a challenging entry standard for regular runners. It also has a robust research arm, and much of the data scientists have on ultra­runners was gathered there.

Hoffman said ultrarunners’ age and experience also means that any hidden cardiac problems are likely to have surfaced earlier in their running lives.

Ultra-fast facts

Ultra finishers get belt buckles

This tradition started in 1974, when logger Gordy Ainsleigh ran in a 100-mile horse race in California. He received a finisher’s belt buckle just like the horsemen got, and the tradition stuck. The pedestrian version of the race became the Western States Endurance Run.

World’s longest

Courtesy of Sri Chinmoy Marathon Team

The longest race on a certified course is the Self-Transcendence 3,100 Mile Race, which consists of 5,649 laps around one long block in Queens, N.Y. The District’s Suprabha Beckjord finished the race 13 times.

World’s largest

South Africa is home to the inaccurately named Comrades Marathon, which accepts 20,000 runners and is set on about 56 miles of roads between Durban and Pietermaritzburg.

U.S.’s oldest

The JFK 50 Mile began in 1963 after President Kennedy challenged the country to get fitter. It is also usually the largest U.S. ultra, with about 1,000 finishers in most years. This year’s race starts in Boonsboro, Md., on Nov. 21.

Sources: Ian Torrence, coach with McMillan Running; Western States Endurance Run; Sri Chinmoy Marathon Team; JFK 50 Mile; Comrades Marathon

As for recent studies concluding that long bouts of vigorous exercise over a lifetime are dangerous for the heart, Joyner said other studies show the opposite, and the question may never be settled because there are so few people to study who don’t have mitigating factors such as coming to running to try to reverse a health problem.

“Exercise is not a vaccine for heart problems,” Joyner said. “But people who have been lifelong, high-volume runners tend to have big, compliant hearts and very good vasodilation” — in other words, very healthy circulatory systems.

Although most ultrarunners don’t have to worry about their hearts during a race, they do have to worry about their stomachs.

Unlike marathoners who can get by with sports drink and maybe a few energy gels to fuel them to the finish, ultrarunners usually need to eat real food along the way — some salty, some sweet, such as sandwiches, potatoes, chips, pickles, candy — which can lead to gastrointestinal distress.

Eating on the run

At marathon aid stations, you’ll find water, sports drink and maybe energy gels. Ultra aid stations have those things plus real food, such as sandwiches, pasta, cake, pickles, soup, burgers, M&Ms, salted potatoes, baby food, bean burritos, soda — occasionally even liquor and beer.

Hoffman said this is probably because blood is diverted from the digestive system to muscles to keep them churning and to the skin to remove heat.

“Digestion is not the body’s priority at the time, so blood is shunted elsewhere,” he said. “Once that happens, there can be certain things that enter the bloodstream from the GI tract that can cause inflammatory reaction throughout the body and cause nausea.”

In some cases, he said, the problem may be simply that the stomach isn’t moving its contents down the line quickly enough, so fluid and food just sit there. In other cases, food is jostled down the line too quickly, causing diarrhea and abdominal cramps.

Runners who don’t manage their food well can “bonk” or “hit the wall,” which occurs when the body runs out of energy and the brain tries to put on the brakes. A unique and instant kind of despair follows — and ultrarunners can hit more than one wall during a race.

“I’ve made every kind of mistake possible,” said Mike Wardian of Arlington, who won JFK in 2007 and is among the country’s most prolific distance runners. “You’ll have really high peaks where you’re be, like, ‘Aw, man, I can do this all day! I’m doing everything right!’ Then five minutes later, it’s the lowest low. . . . ‘I can’t believe I twisted my ankle!’ or ‘I can’t believe they didn’t have chocolate gummy bears!’ I think as the race expands, there are so many more things that can go wrong.”

The list is long, even with proper fueling. Hoffman said that, compared with marathoners, ultrarunners have a greater chance of respiratory problems, cuts and bruises, serious blisters and insect bites — all at least partly attributable to the courses.

Most marathons are run on exactly 26.2 miles of asphalt streets, which are wide enough to accommodate lots of runners, flat enough to not scare away the masses, smooth enough to allow for even pacing and accessible enough for fans who want to watch. Many offer prize money and some, such as Boston, Chicago and New York, offer six-figure paychecks for first place.

Most ultras, at least in the United States, are the exact opposite.

They often occur on rocky, root-filled, narrow, steep and slippery trails with big elevation changes. Organizers gleefully scare people away with names like Mountain Masochist, Badwater, Bear Bait and Frozen Dead Guy. Most offer little or no prize money.

And the distance is almost always a ballpark number because trails are so hard to accurately measure. That means a 100-mile event could actually be 99.4 miles or 110 — which is just as well because most courses don’t have many mile markers.

[How a doctor trained for an ultramarathon]

The uncertainty can make pace-obsessed former marathoners crazy, and the transition can be unnerving even for the fast folks.

“I had no idea where I was on the course,” said Hage of his 2002 JFK 50 Mile (which is actually 50.2 miles, according to race director Mike Spinnler). “You’re running through the woods; it’s easy to get lost. That’s never an issue in a marathon. You can still figure out your splits and go, ‘Oh, that last mile was a little slower, a little faster.’ But in an ultra, the lost-in-the-woods feeling prevails.”

Ultrarunners often carry many of their supplies because aid stations can be spaced 10, 20 or even more miles apart, compared with every mile or two in most marathons.

Packing light

Ultrarunners have to be more self-sufficient than marathoners because aid stations may be hours apart, but they don’t want to weigh themselves down. Some things they may carry: rain gear, gloves, an ear warmer, duct tape, wet wipes, toilet paper, antacid, painkillers, anti-chafing lube, quick-energy snacks.

“The main difference in an ultramarathon versus a marathon is that you have to make sure you take care of issues before they become a real big problem,” Wardian said. “If there’s a rock in your shoe or something, in a marathon you could be, like, ‘Okay, that’s going to suck for 10 miles,’ but if you’re out there [in an ultra] and it happens at the same point and you don’t address it, that little rock can become a huge blister, and it can be the difference between finishing the race and not finishing.”

The terrain, the unknown and the solitude mean that ultras require a different frame of mind for runners trying to conquer a new distance for the first time.

“You have to almost trick your mind that you are invincible and that you are going to finish this,” Fitzgerald said. “The ultras allow you to do something that’s awesome, but you do it at your own pace. You don’t have the pressure to finish in a certain time. As long as you’re finishing, it’s considered awesome.”

Editor's picks

The health hazards of sitting

We know sitting too much is bad, and most of us intuitively feel a little guilty after a long TV binge. But what exactly goes wrong in our bodies when we park ourselves for nearly eight hours per day, the average for a U.S. adult?

How to work out at work

The Post's infographics department tested 12 exercises for a week to see which ones real people could incorporate into a workday.

How to stay healthy in the office

If you spend more waking hours in your office than with your significant other, you and your workspace had better be a good match.

Why you feel so lousy after a huge holiday meal

One ridiculous meal won’t make you fat, but it can make you — and those around you — uncomfortable.