Courtesy of Jenna Wolfe

Jenna Wolfe grins at the camera as she races in a 2011 Girls on the Run 5K, an event that pairs adult "running buddies" with preteen girls who've spent weeks training to run the 3.1 miles. (Jenna's buddy isn't in this picture -- she's just ahead, crossing the finish line!)

There's a good chance I came up with the concept of Girls on the Run, a non-profit that helps preteens train for a 5K, when I was in fourth grade. I was a wide-eyed, incredibly energetic tomboy whose favorite "subject" in school was Phys Ed. (Don’t laugh.) I truly spent the majority of my brain cells trying to get my girlfriends to run around with me outside. Instead, I played with the boys by morning, skinned up my knees by day, and by night, listened to my mom ask me where her daughter was. 

I didn't really fit in. 

By my preteen years, I was still athletic, but at my school, it was uncool to run around, uncool to break a sweat, uncool to be athletic. I was laughed at by the other girls, stared at weirdly by the boys, and once again -- I felt different from everyone else. I didn't know where I belonged.

I never quite fit in as an athletic young girl growing up, but I’ve always been that way. I played sports in high school, as well as in college. I was a sportscaster on TV for 12 years before coming to TODAY. I’m also a personal trainer on the side. And like many athletic women, I just plowed my blind way through the world, feeling on my own as a young female jock.

So when I was first introduced to Girls on the Run, a youth development program that uses running to motivate, inspire and instill in preteen girls a sense of self-esteem, confidence and a healthy lifestyle, I warmly embraced this amazing group of women. They do such important work. They impart wisdom, guidance and soul-growth onto young girls who crave it growing up, no matter how socially settled they think they are.

I participated in a Girls on the Run 5K event with a group of girls last year. The way it works is that each adult partners up with a young runner. Of course, I came in looking for which adult was going to partner up with me, only to realize I was the adult. But once we got that settled, I met up with my little athlete and we were off. About a quarter mile from the finish line, she cramped up. So I pulled a “Jenna” and hinted that I'd be happy to carry her to the finish line. (I’m so competitive.) She looked me square in the eyes and said, "If I started this on my own, I'm going to finish it on my own.”

With that, she started walking (limping) to the finish line. And, wouldn't you know it, her friends, who could have easily run past her, all walked by her side to the very end. That’s when it clicked for me, and that’s when I committed to helping this organization out however and whenever I could.

I struggled growing up as an athletic girl. I shouldn't have had to.

Jenna continues to participate with Girls on the Run, most recently by speaking at a fundraising event. The 5K events are open to the community, and many are happening this week -- click here to find one near you!

More by Jenna Wolfe: 

• When personal training doubles as therapy
• Are you man (or woman) enough for a strongman workout?

More from TODAY Health:

• Skyscraper runners take workouts to incredible heights
• Why does running make my nose run?
• Marathon runners' cardiac arrest risk quite low, study finds

Courtesy of New York Road Runners

Runners race up the 1,576 steps of the Empire State Buildling.

Sprinting up 86 flights of stairs of the Empire State Building -- even if it's for a worthy cause -- is not everyone's idea of a good time. Especially when there's an elevator nearby.

But tonight, more than 650 participants will take the long way up one of New York's most iconic landmarks at this year's Empire State Building Run-Up. It's the 35th annual running of this grueling 1,576-step vertical climb from the ground floor to the Observation Deck.

The event features some of the world's top athletes in an emerging sport known as skyscraper running, tower running, or competitive stair climbing. Held in some of the world's tallest buildings -- like Taiwan's Taipei 101, Chicago's Willis Tower and the Menara Tower in Kuala Lumpur, Malaysia -- participants run stairwells against the clock. (In case you're curious, Towerrunning holds extensive information on many upcoming national and international races.)

Last year's male winner from Germany, Thomas Dold, dashed up the 86 stories in a little more than 10 minutes; an Australian named Alice McNamara won the woman's race in just over 13 minutes.

Likely to be in the front pack of females this year is Cindy Harris, an Indianapolis accountant who has finished among the top three women for the last 13 years.

Harris has won the women's race four times with a personal best of 12 minutes, 45 seconds. She's hoping to come in under 13 minutes this year.

Taking the stairs: TODAY anchor races up skyscraper

A recreational runner, Harris says her running buddies talked her into trying a stair climbing event in Indiana more than a decade ago. Once she completed that, they convinced her to give the Empire State Building Run-Up a shot.

Courtesy of New York Road Runners

Cindy Harris, a four-time winner of the Empire State Building Run-Up, rounds the 20th floor during the 86-floor climb in 2008. Harris finished second among females that year. Haris was the top-placing female in the race in 1998, 2000, 2001 and 2003.

The 43-year-old has been doing it ever since with four first-place trophy replicas of the landmark building to show for her efforts. 

To prepare, Harris trains in the stairwells of 15-story and 30-story office buildings twice a week. In addition, she keeps up her cardiovascular stamina by running, mostly in 5K up to half-marathon distances, and also works in some Pilates to keep her core muscles strong.

As for technique, Harris tends to take the stairs two or three at a time, and she uses her arms on the railings to lessen the load on her legs. At 5-foot-2, she lacks long legs, but a big part of stair climbing is the mental toughness needed to push past the pain and exhaustion.

"It's pretty intense and you're breathing hard for almost the entire time," admits Harris. "Your legs get heavy and you feel it in your quads."

For top competitors like Harris, a stair-climbing race is a roughly comparable workout to a fast-time in a middle-distance run, like a 5K (or 3.1 mile run), says Dr. Joseph Ihm, a physiatrist at the Rehabilitation Institute of Chicago's Spine & Sports Rehabiliation Centers, which hosts the yearly SkyRise Chicago at the Willis Tower. (Once called the Sears Tower, this 103-floor, 2109-step climb occurs every November.)

When stair climbing, the main muscles used for power are in the lower body -- the glutes, hamstrings, quads, and calves, Ihm explains, with arm muscles playing a much smaller role to propel athlete's vertically. Pacing yourself is key, whether you're a top competitor or first-timer. 

Top stair climbers are moving at a pretty good clip, so they're very winded at the end of the event, similar to what you'd see in middle-distance runners, says Ihm.

"When I'm done, it feels like a runner's high," says Harris. But when she's back home in Indianapolis, her coworkers might tease her if they catch her taking the elevator up to her 11th floor office.

Update: Back in 2009, TODAY's own Jenna Wolfe did the Empire State Building Run-Up. (Somehow, we're not surprised.) Watch her experience in the video below.

Have you tried competitive stair climbing? Would you? Tell us about your strangest, most strenuous workouts on Facebook.

More fitness stories: 

• Bod4God: How faith can help fitness
• Marathoners' cardiac arrest risk quite low, study finds
• Sweaty, chatty, messy exercisers: Your biggest gym pet peeves

Carolyn Kaster / AP

Ruben Garcia-Gomez of Mexico City, Mexico, wears the number 1 bib as he and other runners lead the pack at the start of the Marine Corps Marathon in Arlington, Va., on Sunday, Oct. 31, 2010.

It's a sad headline we've grown accustomed to seeing in the hours after many popular long-distance races: a runner collapses and dies of cardiac arrest, often heart-breakingly close to the finish line. Just this fall, a 35-year-old man died while running the Bank of America Chicago Marathon Oct. 9; a 37-year-old man died Oct. 30 at the Dodge Rock 'n' Roll Los Angeles half-marathon; and two men -- one 21, the other 40 -- died at the Philadelphia Marathon on Nov. 20. 

But according to a new study examining 10 years of marathon and half-marathon races in the U.S., the risk of cardiac arrest in long distance races is actually quite rare. (It's kind of like the plane crash effect: Both events, while undeniably tragic, are reported so widely precisely because they're so rare.)

The report, just published online in the New England Journal of Medicine, examined the number of cardiac arrest cases in runners participating in marathons and half marathons in the U.S. from Jan. 1, 2000, to May 31, 2010. Of the 10.9 million runners, 59 suffered cardiac arrest.

In other words, "marathons and half-marathons are associated with a low overall risk of cardiac arrest and sudden death," write the study authors, a team led by Dr. Aaron Baggish, a Massachusetts General Hospital cardiologist. Cardiac arrest, by the way, is different from a heart attack. It happens when an arrhythmia, or abnormal heartbeat, causes the heart to stop beating -- and it can cause death within minutes if the person doesn't receive medical attention.

"This is a pretty careful study, and it starts to give some more insight into who those people are," says Dr. Paul Thompson, a cardiologist at Hartford Hospital in Hartford, Conn., who assisted Baggish with the report and has studied the link between running and heart problems. (He has, oh, just a smidge of experience with marathons himself: In 1972, he qualified for the U.S. Olympic Marathon Trials in Eugene, Ore., and four years later, he finished 16th in the Boston Marathon.)

Those who suffer cardiac arrest during a long-distance run are more likely to be men, particularly older men. In fact, 51 out of those 59 recorded cases were in men. (In the general population, cardiac arrest affects men about twice as often as women.) And most of them had some sort of underlying, perhaps undiagnosed, heart issue -- most  often, hypertrophic cardiomyopathy, a condition marked by a thickening of the heart muscle, which makes it harder for the heart to pump blood.

But the rate of cardiac arrest in marathons, while low, is increasing: The study found 0.71 cases per 100,000 runners from 2000 to 2004, compared to 2.03 per 100,000 from 2005 to 2010. Of course, that's likely because of the transformation the marathon has undergone in the last 10 years, from something only an elite athlete would ever attempt -- to an item that might even appear on the average American couch potato's bucket list.

For example, in 2010, approximately two million Americans ran in full or half-marathons -- compared to less than one million who raced those distances in 2000. And by looking at the average finish times in some of the country's most popular races -- like the Chicago Marathon, which had 45,000 participants in 2011 -- it becomes clear that more casual runners are now participating: At this fall's race, the average finish time was 4:40:34, which is almost 20 minutes more than 2000's average finish time of 4:21:46. 

"Unlike professional athletes that go through a very rigorous screening process -- you don't have that kind of screening before training for a marathon or half marathon. You can just start," says Dr. Kousik Krishnan, a cardiologist at Rush University Medical Center in Chicago who specializes in cardiac electrophysiology and sudden death -- and has run 10 marathons since his first in 2003.

Thompson explains that one of the big debates among cardiologists is whether everyone who wants to run a marathon should be given an exercise stress test, to screen each person for underlying heart condition -- like hypertrophic cardiomyopathy. Often, the answer is "no," because such tests can come back with false positives. "But this study suggests that it may be useful in people who are going to run marathons," Thompson says. 

Have you run a full or half marathon -- or are you training for your first one now? What made you want to attempt it? Tell us what motivates you to keep running on our Facebook page. If your story inspires us, it might appear in an upcoming TODAY.com post!

Related:

• Why does running make my nose run?
• 5 weird things that happen to marathoners' bodies
• Running a marathon can break your butt

It sounds like the setup to a really corny joke: Every time I run, my nose runs, too! (You'd better go catch it, etc.) But it's a real nuisance for runny-nosed runners -- including TODAY's own Kathie Lee Gifford, who wondered aloud on Wednesday's broadcast why jogging left her congested and miserable. (You can watch that video here -- it's at 1:45.) So what's going on?

It's called exercise-induced rhinitis, and it's a lot like allergic rhinitis -- also called hay fever or nasal allergies. For the unlucky people with EIR, as it's called, a good workout triggers allergy symptoms: congestion, sneezing, runny nose, itchiness, general misery. 

Just like regular allergies, exercise-induced rhinitis is common among both "real" and recreational athletes -- whether they have an underlying nasal allergy or not (but it is more common in those who do have allergies), according to a 2006 report. And you're not imagining things: rhinitis symptoms are more common in the winter, the lead author of that study, Dr. William Silvers of the Allergy Asthma & Immunology Clinic of Colorado, said in an email. (Think of a skier's nose, he points out.) It's more common in people who exercise outdoors, but it can also happen indoors, Silvers says. 

Between 10 percent and 20 percent of Americans suffer from allergic rhinitis, but, strangely, 40 percent of endurance athletes suffer from the condition. And while it's well-known that exercise can trigger asthma, hives and anaphylaxis (a life-threatening, whole-body allergic reaction -- that's right: in rare cases, exercise can and does kill), it's not well-understood what triggers the annoying allergy-like symptoms. But the latest theory medical research is narrowing in on is, perhaps unsurprisingly, pollution. In particular, nitrogen dioxide -- found in car exhaust -- has been the subject of a handful of recent studies involving allergies and athletes. 

Of course, runners aren't the only ones who have respiratory problems triggered by physical exertion -- swimmers, divers, boxers, skiers and figure skaters get similar symptoms. Interestingly, exercise-induced asthma is disproportionately seen in Winter Olympic athletes, reported a 2010 New York Times blog post.

Exercise-induced rhinitis won't cause you any real harm -- it's more of a nuisance that, as Silvers phrases it,"snots up your nose and clothes!" But if you regularly work out and your nose is really bugging you, a nasal spray -- specifically, ipratroprium bromide nasal spray -- can help. If the irritation is in your lungs, Silvers recommends using an albuterol inhaler before exercise, and as needed after that.

Readers, do you ever experience allergy or asthma symptoms while working out? How bad is it, and how have you handled it? Here's one suggestion from a wise-guy Twitter follower of mine: 

Related: 

Running a marathon can break your butt

5 weird things that happen to marathoners' bodies

Are you running yourself to death?