Don’t Just Feel the Burn. Understand It.

I try not to let my day job at Nebraska Wesleyan University cross streams with what I write for my blog job. (Well, I guess there was one time…)

Every kid who grew up in the ’80s knows crossing streams is a bad idea. (“Ghostbusters,” 1984)

But a recent article I wrote about a tremendous athlete at NWU warrants an exception. Reagan Janzen is an All-American 800 runner, a conference champion, an Academic All-American, and an NCAA Elite 90 winner (for the highest GPA at an NCAA championship). She holds multiple school records.

Sadly, I don’t think she’s a gravel cyclist (yet). But her pre-race nerves, her coping strategies for the pain she experiences inside a race, and her understanding of what’s actually happening inside her lungs and legs when she goes full-send are all pertinent to us cyclists. Her collegiate career is over now, and she’s moved on to work in Minnesota as an ICU nurse at the Mayo Clinic. But with an athlete and person like Janzen, it’s never too late to become a fan.

So I’m giving that article a second home here (with some snarky photos and captions added after the fact). I hope a few cyclists get some good out of it.


Reagan Janzen (left) prepares to pass in a 4×800 relay at NWU’s Abel Stadium. (Photo, Nebraska Wesleyan University)

Full-throttle Physiology: Feel the burn with NWU’s greatest 800 runner.

Reagan Janzen (BSN ’22) could set her watch by her race-day jitters. Twenty minutes before every gun, the fastest 800-meter runner in Nebraska Wesleyan history would feel the same thing.

“I’ll get scared—like physically frightened—because you know how bad it’s going to hurt,” she said.

The particular burn that 800 runners feel isn’t special, exactly. NWU swimmers and cross country athletes can describe similar pain. But an 800 tucks that pain into a physiological grey area—a place where the white-hot demands of an anaerobic sprint blur into the darker shades of aerobic endurance.

If you’re not the running type, a couple definitions will help.

Aerobic efforts are sustainable for long periods because they’re low enough to be fueled with the oxygen you breathe.

Anaerobic efforts demand more energy than your heart and lungs can deliver. Your body makes up the difference by turning to a secondary energy source stored in limited supply inside your muscle cells. Once those stores are gone, you’re done.

I need that pain to be so present in that 400- to 600-meter stretch. I have to feel it and understand it and be OK with it.

-Reagan Janzen

“That’s what makes the 800 so difficult,” said Samantha Wilson, director of NWU’s Master of Athletic Training Program. “It has you teetering between those two very different energy systems.”

Too for to sprint and too short to pace out, Wilson called the 800 “that odd distance humans just aren’t meant to run.”

Janzen, then, is that rare runner who’s learned to thrive in this inhospitable place.

Janzen “in that inhospitable place” (Photo, NWU)

A mental tuck

Before Janzen, no NWU woman had ever cracked 2:15 in the 800. Then came Janzen’s blistering 2:09.74. This nearly six-second gap equates to about 120 feet on the track—the rough length of three city buses—between Janzen and the old school record.

Three bus-lengths = a healthy lead. (Photo,

“An 800 gives you long enough to really think about that pain,” she said. “And it forces you to make decisions inside that state.” For Janzen, that pain during the race—and those key decisions that come with it—arrive just as predictably as her pre-race jitters.

“The first 400 meters almost always feel fine,” she said. Then, somewhere within several meters of this halfway point, her pain slinks out, like a childhood monster from beneath the bed.

Saw you comin’. (Photo,

“By this point, her muscles are flooding with lactic acid,” said Associate Professor of Health and Human Performance Tamra Llewellyn (’06).

“A lot of people assume lactic acid is what causes that pain, but that’s wrong,” Llewellyn said. “You could inject lactic acid into your muscles, and you wouldn’t feel a thing. It’s just a measurable marker of a different kind of energy burn.”

Like soot after a fire, lactate levels show an anaerobic effort has happened. But the true chemical culprit behind the burn in Janzen’s legs, Llewellyn said, is pyruvic acid—physiology’s pyromaniac.

I suspect a fire may have come through here… (Photo, Los Angeles Fire Department)

Rather than try to avoid this sensation, Janzen learned to treat her pain as a mental cue. Its first flares confirm she’s running according to her own ferocious plan.

“I need that pain to be so present in that 400- to 600-meter stretch,” she said. “I have to feel it and understand it and be OK with it.” Pain may be onboard, but it isn’t driving.

Then Janzen made a small, defining gesture. She lifted her hand and tapped behind her ear at the base of her skull. “I have to tuck that pain back here in my mind.” Another little tap. “I have to tuck it and keep going.”

Sounds easy, right? Just tuck it and run.

Wilson laughed. “There’s nothing easy about it.” What Janzen is attempting to “tuck” neatly behind her ear in the final 200 meters of her race is nothing short of a physiological housefire.

An actual image of Janzen’s lungs in the closing meters. (Photo, Indianapolis Fire Department)

Intensity you can taste

“Your brain runs on glucose,” Llewellyn explained. “And at this level of effort, your glucose is dropping so fast that, if you actually could hold that pace, it would become physically dangerous for your brain after just four or five minutes.”

Janzen knows she’s running an 800; she knows she’ll relent after about two and a quarter minutes. “But her body doesn’t know that,” Llewellyn said. “And it’s sending out all sorts of warning signals to protect itself from damage.”

By now, Janzen’s heart cannot push any faster. Llewellyn said athletes can see a five- to eightfold rise in the amount of blood coursing through their pulmonary system each minute during maximum effort. The resulting crush of red blood cells has an effect on Janzen’s lungs that she can actually taste. The strain is greatest at that delicate point where the air Janzen breathes touches the blood she pumps.

“This point of oxygen transfer to the bloodstream is remarkably thin,” Llewellyn said, “like two cells wide.” And as those red blood cells slam against these thin barriers, some iron-rich hemoglobin slips across the cellular fence.

Cram 500% of the red blood cells coursing through these narrow vessels in a given minute, and you get a tight squeeze. (Image, Jennifer Pinto)

As Janzen holds her sprint, her lungs take on fluid. “You could describe it as an exercise-induced pulmonary edema,” Llewellyn said. And that fluid takes on this freshly squeezed hemoglobin.

As a result, Janzen’s straining lungs are expelling trace amounts of iron with each exhale. And once she stops running long enough to process her senses, she’ll taste blood.

The taste is so strong that unfamiliar athletes sometimes believe their lungs are bleeding. Wilson compared this taste to the smell of a bag of microwave popcorn. “When you put the bag inside and shut the door, you don’t smell anything.” But once you really heat up that system and the corn starts popping, “you can smell it from across the kitchen. The door’s still shut; there isn’t any popcorn ‘bleeding’ out of the microwave. But you can still smell it across that barrier.”

That taste of blood after an intense anaerobic effort, Wilson said, is like that escaped smell. Janzen’s not bleeding; she’s just cooking on high heat.

Our greediest organ

As the clock ticks over two minutes, weird things are also happening inside Janzen’s mind. The human brain is our greediest organ, demanding lots of glucose, oxygen, water and sleep to perform. (That’s why NWU students are wise to enter final exams well-rested, well-fed and well-hydrated.)

An 800 sharply diverts blood, glucose and oxygen away from the brain in favor of the legs. And the brain doesn’t enjoy being shortchanged.

When athletes “see stars,” it’s often the result of modest glucose and oxygen depletion in the vision center of the brain—the same spot behind her ear where Janzen mentally tucks her pain. Deprived of sugar and oxygen, this portion of the brain nods off—with sparkles much like the tingles in your foot when you cross your legs too long.

The body has a simple solution to the problem of too much blood down low in the legs and not enough up high in the brain, Llewellyn said. You’ll see it at the finish line of any track meet.

“Dizziness and fainting are the body’s way of forcing you into a horizontal position.” When you lie down (or tip over, the body doesn’t much care), your heart no longer has to fight gravity to redistribute blood back toward your greedy brain.

Yeah, it may hurt. But full efforts have their payoffs. Janzen (right) and teammates celebrate a conference championship. (Photo, NWU)

Pain with a purpose

For Janzen, the weirdest thing about these intense physiological sensations is the equally intense calm that comes with them. “As runners, we practice what things feel like,” she said, “so we’re not surprised when we’re going through it.”

This ability—not to ignore pain, but to understand it and work through it—is the essence of “running tucked.” For Janzen, it’s a mindset that applies beyond the track.

Janzen’s calm as a runner directly applies to her poise as an ICU nurse. (Photo, NWU)

Janzen, a Hampton, Neb., native, earned her Bachelor of Science in Nursing in May with a perfect 4.0 GPA. Then she moved to Rochester, Minn., to begin work at the renowned Mayo Clinic’s Neurosciences Intensive Care Unit. It’s a job she landed after performing well in a prestigious Mayo Clinic summer externship last year.

“As a nurse, you have to respond to pain and the unexpected with calmness,” Janzen said. “You have to make good decisions, even in a stressful environment where things can change rapidly.”

In track and in nursing, practice and simulations lead to better performance when it counts. (Image, NWU)

Athletes and nurses are very similar that way, she said. Both rely on intensive training. Discomfort doesn’t rattle them. They trust their teammates and appreciate the human body for its power to endure and to heal.

The work can hurt sometimes. But Janzen’s not afraid of it. It’s pain with a purpose. “I’m a religious person—a spiritual person,” she said. “And I can use what I’ve been given as a nurse—my experiences and my gifts—to help people get out of some of those deeper trenches.”

At 22 she understands she’s still young, with decades of learning and growth yet to come. “But I feel like I’ve already seen a lot—and felt a lot—in my life. And I can use that to help people.”

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