6 min readWelcome to Trail Tested, a new monthly column from entrepreneur and athlete Jack Espy as he trains for the grueling Leadville 100 ultramarathon this August. Trail Tested will follow Jack along his journey to do his first 100-miler to see what his body is capable of and what his mind can endure. Throughout his training he’ll be giving us a rundown of gear he’s been putting to the limit.
I’ve been a Garmin loyalist since 2017 with the Garmin Fenix 5. Back then, I bought it strictly for lifting, just to track calories and steps. That was my entire world at the time… calories, calories, calories. I wore that thing through college and deep into my full-blown “gym bro” phase.
Then I upgraded to the Garmin Fenix 6. I rocked that for a couple of years before, for reasons I still can’t fully explain, I decided I needed to become “tactical”. So naturally I bought the Garmin Tactix 6. That watch had every feature imaginable. Including a skydiving mode… which, for the record, I never used. Not even close.
Eventually I grew out of being “tactical”, as I was getting into running around 2024 and wanted a true performance watch. Something that made me feel all-in. The Garmin Enduro did exactly that. I loved it. It honestly helped me fall in love with running. Tracking everything, seeing the data, it just made the whole process simple and addictive. I wore it for about a year… until I tragically left it behind on a work trip. Still not over that one. But I knew the cure: a new Garmin.
So I went back to the Fenix line and picked up the Garmin Fenix 8. It’s one of Garmin’s best, and definitely one of the most expensive. I went with the AMOLED version, so the display is bright, colorful, and honestly just looks sick. The tradeoff is battery life, about 7 to 10 days, and even less for me since I’m constantly using run and trail features.
At this point, it’s safe to say I’ve got a veteran background with Garmin—in nearly a decade of using them, I’ve never had one break or fail on me.
What I Like
The biggest benefit of Garmin is how seamlessly everything connects. The integration with apps like Strava and TrainingPeaks is next level. My running coach Duncan Callahan loads all of my weekly workouts into TrainingPeaks, and this automatically syncs to my Fenix 8. So when I head out for a run, I’m not just tracking it, I’m following the workout in real time, step by step, exactly how it’s programmed.
It gets even better. Through the Garmin Connect app, everything links up with my Shokz headphones when I’m connected to my phone. That means I’m getting live audio updates on pace and mileage while I’m running. Honestly, it’s a game changer.
During a workout, I can easily toggle through everything I need: pace, distance, heart rate, time elapsed, time remaining, etc.. And when you’re training seriously, that data matters. A lot.
Heart rate and pace are everything for me. I need to know I’m in the right zone. Push too hard and I spike into a zone I shouldn’t be in. Don’t push enough and I’m leaving work on the table. The same goes for pace. If my heart rate is high but my pace is slow, that’s usually a sign I’m overtrained or underfueled. If my pace is strong and my heart rate is controlled, that’s when I know I’m in a good spot, recovered, fueled, and ready to rip.
And once the workout’s done, everything flows just as smoothly. My run automatically uploads to Strava, and from there I can share it straight to my socials. No extra steps, no friction.
Another underrated perk is having a rough idea of my daily calorie burn. I know it’s not 100% accurate, but it gives me a solid baseline of where I’m at. As training ramps up, it’s a great way to make sure I’m staying on top of my fueling and not falling behind on what my body actually needs day to day.
I also use the Fenix 8 for everything outside of running. I track my morning lifts on it, and I’ll even use it to time my sauna sessions post-workout. It’s basically with me all day.
What to Watch Out for
I’ve used a lot of different fitness trackers and smartwatches over the years, everything from an Apple to Coros, and nothing fits my needs like Garmin.
That said, there is a bit of a learning curve when you first get started. Garmin packs a ton of features into its watches, and navigating all the settings can feel overwhelming at first. Honestly, I’m still discovering new features, and I’ve been using Garmin for nine years. My advice is to start with an entry-level model, get comfortable with the interface, wear it daily, and actually use the features. As your training evolves and you start preparing for races or bigger goals, then it makes sense to level up to one of the higher-end models. By that point, you’ll already know how everything works and can really take advantage of what the watch offers.
One frustration is the occasional pairing hiccup with the Garmin Connect app. Sometimes it takes a minute to find the watch over Bluetooth, and every now and then it forgets the device. It’s rare, but it happens.
Verdict
Will I be wearing the Garmin Fenix 8 on the start line of the Leadville 100? The answer is… no.
I know, kind of shocking after everything I’ve said. But it comes down to one thing: battery life. Leadville is a different animal. I could be out there for close to 30 hours, which means my watch needs to last at least that long without question.
The Fenix 8 is incredible, but when you’re actively using features like run and trail mode, battery life drops significantly. Instead of that 7–10 day range, you’re looking at closer to 22 hours. And trust me, I’d love to say I’m finishing Leadville in 22 hours… but unless David Roche is physically carrying me up those climbs, it’s probably not happening.
So because of that, the Fenix 8 is out for race day. What I’ll be wearing instead is the Garmin Enduro 3.
In my opinion, it’s the ultimate ultramarathon watch. It has everything the Fenix 8 offers and then some, but the real differentiator is battery life. The last thing I want during a race like Leadville is even a hint of stress about my watch dying. Been there before at Black Canyon 50K… not doing that again.
I want to trust that my watch is going to show up for me, just like I’m showing up for the race. The Enduro 3 is an absolute workhorse, with battery life that can stretch up to 90 days in smartwatch mode and up to 320 hours with GPS features running.
And honestly, Garmin says it best. The Enduro 3 is “built for the longest runs on earth…” If that’s not the perfect watch for Leadville, I don’t know what is.
About the Author
Jack Espy is the founder of Strive Soda and Spirited Hive. He is in the midst of a 50-week training regimen with coach Duncan Callahan (two time Leadville 100 winner). His current run mileage is 50 miles per week (typically including one speed day, two recovery runs, one threshold session, and one long run) and his strength training (four days a week) focuses on full body movements to hit every muscle group. Nine months ago he could barely run five miles before challenging himself to tackling the Leadville 100. Now his mile pace is 9:50 while he’s finished races like the Dead Horse 30k, the San Diego Trail Marathon, and the Black Canyon 50k. His current favorite road shoe is the Saucony Endorphin 5 Speed and his current favorite trail shoe is the Hoka Speedgoat.
