The Neurotic Med Student Who Solves FKTs Like Math Problems – RUN

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Over Labor Day weekend, Will Peterson used his sparse time off from medical school to do something no human has done before.

He ran the Long Trail—the 272-mile epic that traverses the rocky, rooty, and relentlessly steep length of Vermont—in just three days, 21 hours, and nine minutes.

America’s oldest continuous footpath, the Long Trail has blossomed into one of the most highly-contested FKTs in the world and is just one of 10 “premier” routes on fastestknowntime.com, the official arbiter of these records. No one had managed to break the four-day barrier. Until now.

During a time of increasingly professional FKT operations funded by shoe brands and documented by film crews, Peterson, 25 and now in his third year of med school at Dartmouth, is quick to point out that his effort was entirely “unprofessional.” No outside funding, all local volunteer support. But “unprofessional” is a homonym, and while Peterson’s performance may embody one meaning (not a paid occupation) it’s quite antithetical to the other (inept and unskilled).

Med school impedes Peterson’s athletic pursuits in many ways, namely sucking away time and energy. But after pouring through his Long Trail write-up, as well as his own podcast, I’m beginning to wonder if the rigor of school illuminates—and dare I say, cultivates—another one of his skillsets that’s absolutely imperative to excelling at these types of efforts. That’s why we’re on a Zoom call one fall morning.

“I got three hours of sleep last night,” he says with a smile. “So forgive me if my brain is working a little slowly.”

I remind him that he was the one who wanted to meet even earlier. And so the psych eval begins.

Video credit: Philip Carcia

The New Englander Advantage

On fitness level, Peterson figures he can’t compete with the likes of Tara Dower and Jack Kuenzle, two fellow east coast record-setters who can spend all day essentially every day training. But where he can get an advantage is in the preparation.

“I don’t have the time to train a ton, but I do have time to do so much planning and math on it,” Peterson says. “If I can level the playing field a little bit by one, knowing the terrain really well, and two, just essentially knowing what I need to be doing at every second, that to me is worth a lot of time and you can make up what is probably like a relatively decent fitness gap.”

Peterson’s been learning this terrain defined by highly fractured and metamorphic rocks like granite, gneiss, and schist, resulting in rocky outcroppings, steep slopes, and large boulders that the “trail” simply runs straight through for nearly his whole life. For starters, he’d already set a record on the Long Trail. In July 2023, he ran the whole thing without any outside help and with 30 pounds of supplies on his back to set the unsupported FKT. He finished just seven hours behind John Kelly’s overall mark, set with a team of support three weeks previously.

Plus, Peterson grew up not far away in western Maine, playing soccer and skiing but immersed in the terrain nonetheless. He took to backpacking as an undergraduate student at Northeastern University in Boston. That affinity led to him taking a semester off in 2019 to thru-hike the Appalachian Trail, and he intended to thru-hike the Pacific Crest Trail the following year until the Covid-19 pandemic derailed his plans.

That’s when he discovered the world of FKTs and began attacking New England’s gnarliest, most prominent routes as local, hyper-condensed ways to satisfy the adventure itch. What he lacked in race experience he made up for with the problem-solving skills he’d acquired through backpacking—and his studies.

“Like a Neurotic Med Student”

Like familiarizing himself with the terrain, the planning process for the Long Trail was practically innate. Peterson is obsessed with controlling and optimizing every variable—in environments that are inherently unknown, unpredictable, and out of control.

“It’s the classic neurotic med student,” Peterson says. “I need to control every variable that’s controllable.”

There are a lot of logistics that go into a multi-day effort: pit stops, nutrition, sleep, pacing, and gear, just to name a few, and Peterson was determined to optimize all of them, including perhaps the biggest variable of a supported FKT: assistance.

“I just always look at things like this from a numbers perspective,” he says. “And so I was like, ‘OK, if I’m going to do this, I need to absolutely maximize the benefits of a supported effort versus an unsupported effort.”

That meant ensuring he had enough pacers lined up to have one, probably more, people with him on trail at all times to literally set the pace, navigate, and carry his gear and nutrition. It meant having a crew bumbling through the backroads of Vermont to meet him at every trailhead for a Formula 1-like pitstop (spearheaded by his dad and mom, who had an uncanny ability to tune into Peterson’s needs), if it’s time to sleep, get him to sleep immediately, and send him back on the trail. (He slept for a total of less than seven hours.)

“It’s stuff like that,” Peterson says. “I hate the idea of someone beating me because their logistics are better, or because they carried less than me. If someone beats me, I want it to be purely that they are faster, they are better.”

These efforts aren’t purely an athletic endeavor, he says. “If we were doing that, we’d just be running around a track. It’s a logistical endeavor, and all of the teamwork components that sort of go into it.”

Just Another Math Problem

Planning began months in advance, largely with Xander Keiter, his good friend from childhood, and Bill Tidd. Tidd, 62, is a legend in the New England trail running community, who outside of his day job as an engineer is a prolific racer (he finished the Cascades 100-miler just days before Peterson began his effort) and has set some of the gnarliest, most logistically complicated and renowned FKTs in New England, including the New Hampshire 48 4,000-footers. It’s a record he took from Peterson—at Peterson’s encouragement.

Beyond his athleticism, what makes Tidd so special is his analytical mind. Before his NH 48 record, Tidd developed a formula factoring in his own heart rate data, every variation of the potential routes, and every other variable he could think of to spit out a plan.

“He solved the New Hampshire 48 like a math problem,” Peterson said. “And then he developed an algorithm to spit out the ideal New Hampshire 48 route.”

Tidd developed another algorithm for the Long Trail based on Peterson’s unsupported effort and the fact that he was carrying a 30-pound pack to estimate what Peterson’s supported splits would look like. He split up the Long Trail into five-mile segments, providing an average pace projection for each.

“That was basically my whole plan,” Peterson says. “Just trusting him and saying, ‘OK, this formula’s gonna work.’”

Peterson took Tidd’s formula and busted out a tool he’s all too familiar with from med school—flashcards. He created flashcards for each section, hand-writing the distance, elevation, his projected pace and splits, and notes to himself that he could reference during the effort. That allowed him to turn his brain off on the trail and save precious mental energy. Just follow the formula.

It worked.

“The splits were remarkably close to what I actually ran,” he says. “His formulas predicted almost every section. It was pretty ridiculous.”

Certified Local

Beyond Tidd and Keiter’s help with the planning, Peterson amassed a crew of over 30 northeasterners to come out and support him on the effort itself—half of whom volunteered sight unseen after he put out a call on Instagram. There was a core crew of six who supported him throughout the four days, plus a handful of rotating crew members and 26 pacers. They ended up proving instrumental to so much more than the actual operation. Turns out, being so prepared came with a major downside.

“The whole thing about FKTs for me is that they bridge this gap between competition and adventure,” Peterson says. “And the more you ruthlessly scout a route, the less it feels like an adventure.”

Peterson knew the trail so well already, he was not going to find adventure or excitement in wondering what’s ahead. Instead, he found it in who was around him. In addition, all 26 volunteers were from the northeast, most of them from northern New England. Peterson took more than pride in the local nature of the operation.

“Part of my motivation this year was I kind of wanted to reclaim the Long Trail for the locals,” Peterson says. “I thought that it would be cool if the locals could be the first ones to take the record under four days.”

But with a big support crew came a big responsibility.

“My biggest fear in this effort was wasting peoples’ time,” Peterson says. “There were so many people both who I knew and who I didn’t know who were burning significant amounts of time to come out with me.”

That stress was compounded by a key variable entirely outside of his control: the start date. Someone with nothing else to do might wait for the perfect weather window to open up over perpetually fickle northern New England—an area that has suffered destructive hurricanes the last two summers. Peterson had one slot off from school to get it done, plus he didn’t want to leave three dozen people hanging. He set the start date for August 28 and crossed his fingers.

An Iron Will

Rain battered the car the length of the two-plus hour drive from Peterson’s home in Norwich, Vermont, to the Long Trail’s northern terminus near Jay Peak, right on the Vermont-Canadian border. But the skies cleared just as Peterson—along with his parents, Eric and Ann, and Keiter— arrived. Save for some rain near the end, the weather cooperated for most of the effort. But he had plenty of obstacles thrown in his way nonetheless.

Things started going sideways almost immediately. In perhaps the epitome of Peterson’s need for control, he planned to run all 272 miles fueled exclusively by Infinit, a customizable drink mix with carbohydrates, protein, and electrolytes. His rationale came down to familiarity—he’s been using Infinit since his NH 48 record—and simplicity. By fueling exclusively off of this one product, he would know exactly how many grams of carbohydrates, protein, and electrolytes he was consuming at all times.

“It completely goes back to dialing in the logistics and making everything as simple as I can possibly make it,” Peterson says. “For example, what Joe McConaughy ate on the Long Trail, and I would get so confused by it. It was like a bunch of cookies, nuts, Oreos jammed into his water bottle, and like all this stuff.”

Peterson shudders thinking about it.

“When I’m 150 miles in, I would not be able to think, OK, I’m getting this many calories. I’m getting this many carbs, this much protein, this much electrolytes. With the liquid nutrition, I know I have this flask and if I drink this flask in the next hour, I’m good on everything.”

Controlling his nutrition also gave the med student peace of mind. He knew his kidneys would be just fine as long as he stuck to the plan. “It’s a no-brainer for me. It takes out a pretty large variable, as long as my stomach can hold it down.”

As long as.

As the sun fell on day one, Peterson started growing nauseous. He was puking by 9 P.M. That’s when the guilt settled in, too.

“I was so worried that I was going to waste all these people’s time. That would be such a lame way to flame out, you know?” Peterson says. “We’ve planned and trained for this whole thing, and then it’s just going to be like, ‘Oh, Will’s little tummy can’t hold down food.’”

He figured the stomach distress was just a bump in the trail he had to overcome, and he kept drinking the Infinit. But behind the scenes, Tidd had a conversation with the rest of the crew. He hypothesized that maybe Peterson was having a psychosomatic reaction to the drink mix—too many hard efforts associated with the taste—and he simply needed to mix it up. Or maybe Peterson’s stomach wasn’t tolerating the protein and electrolytes. Tidd suggested that Peterson try drinking some Maurten drink mix, which doesn’t have protein or electrolytes, on the uphills instead. The nausea and vomiting went away.

Other than a few nibbles of a peanut butter and jelly sandwich and four or five applesauce squeezy pouches, Peterson fueled exclusively off of Maurten and Infinit drink mixes to the finish.

The other big problem Peterson and his crew had to solve on the fly was his quad, which inextricably got progressively more painful over day two, to the point he was reduced to walking the downhills. His crew swung by a drug store and bought him a compressive sleeve. That, along with massage and Ibuprofen (which Peterson admits is “not great” on a long effort like this) helped marginally.

“I knew it wasn’t a tear, because there wasn’t a strength deficit. It was inflammation, but inflammation can lead to tears,” Peterson says. “My med school brain turned off at that point. I went into ‘get to the next checkpoint’ mode.”

Checkpoint by checkpoint, the agonizing pain gradually went away over the next day and never came back.

“I have no explanation for it,” he says. “Maybe I had an electrolyte imbalance which led to muscle spasms. Maybe there was some sort of knot that we were able to work out by constantly massaging it. Or maybe it was a mental thing. My brain was like, ‘We’re gonna do this, so get over it.’ And my body was like, ‘OK.’”

Professionally Unprofessional

Despite some rain, the stomach distress, and the angry quad, Peterson views himself as incredibly lucky. He clicked with all of his pacers, even the ones he’d never met before. The weather was good enough. As the sun rose on the fourth day, Peterson ditched the headlamp, waist lamp, and running belt. He dropped two of his three pacers as he sprinted (at least in his mind) to the Vermont-Massachusetts border. His crew’s mantra, “make life hard for the next person who comes for this record,” materialized.

But I don’t think his success was luck.

Peterson isn’t sure, yet, what kind of doctor he wants to become. “If I had to choose now, I would probably choose psychiatry,” he says. “I’ve just always been drawn towards behavioral issues. I don’t know what that says about me.”

In the context of his consecutive record-setting summers, the answer seems pretty obvious. If setting multi-day records is a test of the mind, Peterson seems to have cracked the code. He plans so thoroughly, he has contingencies for managing the unexpected. He’s ruthless in his pursuit of logistical perfection, and yet he’s not afraid to adapt. And he knows himself well enough to not let his ambition get in the way of his dreams.

Peterson’s at the caliber he could get paid to run—former Long Trail record-holder Kelly works full-time in tech, and he’s also sponsored as a runner by La Sportiva, Ultimate Direction, XOSkin, and Tailwind Nutrition. Peterson, as of now, elects not to.

“I’ll never pay the bills with running,” he says. “At least for me, I feel as though if running were my entire thing I would go crazy and I would be so stressed out about it.”

Hedging his bets, it seems, actually allows him to go-all in during these rare efforts that require everything of his body and mind.

“It is super interesting, because obviously the physical component would be advantaged towards  doing it full time, right?” Peterson wonders. “Because you can just optimize your training and you can go live on the course and scout everything very thoroughly. And all that stuff is very helpful, obviously. But I feel like, anecdotally, I just know so many people who do it full time that the training sucks for them and they kind of hate it and race day is a lot of pressure.”

Sure, Peterson felt pressure on the trail—three dozen people volunteered their time to support him. But it was also the celebration after a long year of school, squeezing in training in the mountains, on the stairmaster, and on the local 150-foot hill wherever school took him to hospitals around New England.

“Because my time’s so limited, every time I get to go train is a pleasure and it’s fun,” he says. “I feel like that has to have a big benefit. I do like two or three of these things a year and that’s it. So maybe you can spend more mental energy on the one or two things that you’re doing if you’re not a full time person.”

He may have only run the Long Trail end-to-end twice, but the unsupported and overall records belong to the locals once again.

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