These TikTokers Exercised 9 Hours a Day For 3.5 Months. Here's How Their Bodies Changed.

@ThruHikers Tim Beissinger and Renee Miller
Courtesy of Tim Beissinger
Courtesy of Tim Beissinger

When Renee Miller and Tim Beissinger (better known as the @ThruHikers) set out on their big adventure for 2022 — a canoeing and hiking route through the Pacific Northwest covering 2,700+ miles in 106 days — they decided to document it all on TikTok.

The couple shared details about everything: how they planned and dehydrated their meals, how they crossed streams and carried their canoe, and even how Miller manages her period while she's on the trail.

One of the TikToks that got the most engagement, however, was the one that documented how their bodies changed throughout the journey. The video, which amassed more than seven million views since it was posted in October 2022, dives into what happened to Miller and Beissinger's bodies from exercising an average of nine hours and 15 minutes per day for three and a half months straight.

The "PNC: changing bodies" video was inspired partly by their followers' curiosity. After watching the two take on such an immense physical challenge, more than one commenter wanted to know, "How much weight did you lose?" So, Miller and Beissinger detailed exactly how that much exercise changed their bodies — and their message was beyond refreshing.

"A lot of people asked if we lost weight — that was a common question we got on our videos," Miller tells POPSUGAR. "But we realized it was more than just weight loss. Our bodies were changing."

The PNC route first involved hiking about 1,600 miles across 72.5 days, from northwest Washington State up into Canada (that's about 20 miles per day). Then, they paddled a canoe back along the entire Columbia River out to the Pacific Ocean, covering about 1,200 miles in another 33.5 days (about 35 miles per day).

They detailed how walking for so long flattened their feet (they were both a full shoe size bigger by the end!); how being outside gave them tans despite wearing sunscreen; how bushwhacking left them with random cuts and bruises; and how walking and paddling gave them blisters, then calluses on their feet and hands.

@ThruHikers Renee Miller and Tim Beissinger with their canoe on the Columbia River
Courtesy of Tim Beissinger

They also acknowledged that, over the course of their journey, they both lost almost all of their body fat and "started looking pretty scrawny," as Beissinger says in the TikTok. But they built muscle, too: first in their legs, while they were mostly hiking; then in their arms, during the canoe portion of the trip.

In fact, after about a week of paddling, Beissinger says he actually shocked himself while changing his shirt. "There was this giant growth on my arm, which was my muscle," Beissinger tells POPSUGAR, laughing. "I felt like a muscle man. It really surprised me when I realized my muscles were growing in directions that they've never grown in before."

Ultimately, they both came home just five pounds lighter, since they'd lost a lot of body fat but gained a lot of muscle.

But the two were careful to point out that these changes weren't permanent. "Now, we're both back at work sitting in front of computers all day. It's unrealistic to maintain the bodies we've built, but we try to stay fit between trips by exercising outdoors at least once a day," Beissinger says in the TikTok.

"A lot of people asked if we lost weight — that was a common question we got on our videos," Miller says. "But we realized it was more than just weight loss. Our bodies were changing.

"Something else we've documented on both of these hikes, that a lot of people on TikTok watched, was how much we eat in a day when we're out there," Beissinger adds to POPSUGAR. "This is not a weight-loss trip; it's more of an eat-everything-in-sight trip," he says. They estimated that he was eating about 4,000 calories every day just to fuel the journey physically.

In fact, Beissinger and Miller say they had trouble eating enough to sustain their activity, especially during the beginning of the trip; at first, the sheer amount of exercise makes you less hungry, Beissinger says. But "after two months of being out there, you're just always hungry and always needing more," Miller adds.

The couple's candid approach to the weight-loss question is refreshing in a wellness culture that often considers exercise to be, first and foremost, a tool for weight loss. Their message serves as a reminder that, for many people, movement — whether a casual lunchtime walk or three-month trek — is enjoyable and fulfilling in itself, and not only used as a way to change your body. Not to mention, bodies will fluctuate (as will your activity level), and that's OK.

The Thru Hikers say their transition back to desk jobs wasn't easy. "There's a phenomenon that people call the 'post-trail blues', which is when you switch from being out on one of these super long-distance trails on, in many ways, like a four-month vacation. You're just so happy. It's so fun. And then normal life can feel mundane and tedious, and it's hard," Beissinger says.

In November 2022, even a couple of months after returning to normalcy, he admitted he was still going through that adjustment period. "When you hike 25 miles a day every day, you always feel like you've accomplished something. And at work, you know, some days I feel like I've accomplished something, and other days, I feel like I didn't. And that's just part of life, but it can be hard getting used to that again."

And, yes, losing his muscle-man physique since returning has been sad, Beissinger says, but it was expected. "It's fun to feel like a superhero when it comes to fitness. But as we said in that video, we accept that that's not realistic and that's not a good ideal to strive for because we can't — nobody can — look like they're at their peak fitness 365 days of the year."