Rucking in Zone 2 for 5K Gains

A tale of 2 different 5K run tests, and the training in between them.

I had heard for a while about the cardio benefits to training in Zone 2 (heart rate at 60-70% of your max), but when I did the math it became difficult for me to find a way to stay in this zone on what I would call “runs.” Any time I’d think to myself “this will be an easy run,” I would end up overshooting HR Zone 2 and going “too fast.” For me in my early-mid 30’s, Zone 2 would equate to about 110 beats per minute (bpm) to 130bpm. On any kind of jog at all, I’d very quickly surpass Zone 2 and get into the 130-150 range, which was training “too hard,” or so the guidance said.

Note: Widely-accepted “age-related” max heart rate works out to be 220 – your age = max HR.

I did not intend to run this experiment, but in hindsight I’m glad things worked out this way. Let’s talk about my baseline (first) 5K run first.

Initial 5K Test

Date: November 25, 2022 (the day after Thanksgiving)

Conditions: clear and calm, low 40s F

Time: 23:57

Average HR: 173

Max HR: 182

11.25.22, with 2022 mustache in his final days

Notes: this felt like a test. I had been working out regularly and wanted to see how I would do with a 5K distance, aiming for my personal best time. At the end I was pretty spent, I would say RPE (rate of perceived effort) for this run was like an 8 or 9. That day, I don’t think I could have gone faster. It was the day after Thanksgiving, but I was well-rested and well-hydrated.

The Training Montage

In-between these two 5K runs, I completed a whole bunch of rucking focused training. I’m pretty often signed up for PATHFINDER Ruck Training and trying to complete Endure or Advanced level, which involves a lot of ruck miles (for me). They usually end up being 2-3 mile rucks, which take me about 25-45 minutes with a ruck weight of 30-50 pounds. Based on my goal pace and the terrain near my house, I’m typically moving at a good pace, aiming to exceed 4mph (go faster than a 15:00/mile pace).

I’ve been doing this for a while with the goal of improving my cardio fitness for sub-30 minute efforts. I volunteer as a firefighter in town and want to get the most out of my SCBA cylinder’s limited air supply. It’s commonly called a “45 minute” air cylinder, and 1/3 of that is the reserve air/time for you to get out of dangerous atmosphere, i.e. your work is done and now time to get out. Thus the 30 minute goal – to maximize amount of work I can do before the alarm goes off.

Training frequency for these type of 2-3 mile rucks: between November and March, approximately 3-4 times per week. I did not complete a PATHFINDER program during this time – I had a habit of putting off challenges or letting life get otherwise “in the way.” But that’s OK. The community is great, their workouts are also great and utilize the same equipment I have at my home garage gym setup, and there’s basically no reason not to be involved. Even if sick kids make you miss your timed 12 mile ruck, etc. If there’s one thing that the conclusion of this tiny study imparts upon you, let it be this:

You do not need to finish the PATHFINDER program to see huge fitness gains. There is a lot of value in going after the ruck miles and the workouts, even if you don’t check every box required to get your patch.

Sure, it is a great feeling to complete your program, earn your morale patch, and all that. But it’s not the end-all/be-all, it was not a waste of time if you “come up short.” The journey is the destination, or something like that. What I’m getting at here is that I spent a few months doing a ton of Zone 2 HR training, in the ballpark of that half hour duration, and saw great benefit. My resting heart rate and HRV have improved over this time, in addition to the pace/speed gains mentioned below.

(Though, due to the stomach bug in the week leading up to the race on 3/25, my HRV (heart rate variability) numbers were out of whack. But +1 for tracking this data: by knowing my normal ranges for resting/awake heart rate and having an idea of my HRV, I knew I was fighting off a bug versus some momentary indigestion, etc.)

Follow-up 5K Test

Date: March 25, 2023 (Schenectady Firefighters’ Cancer Foundation Run 4 Your Life 5K, certified course)

Conditions: clear and calm, low 40s F

Time: 24:23

Average HR: 142

Max HR: 158

Race day, 3.25.23, upper lip bald as per usual

Notes: this run felt… so easy. I was coming off of a stomach bug for a couple of days, which had kicked my butt and made me feel like I didn’t really want to push the pace. I wasn’t going into this one to race. RPE I’d say was about a 5-6, I was moving with a purpose but could have talked with a friend as I ran. Then I looked down at my watch at the 1 mile split.


What? How was this possible? I was hardly trying – I felt like I had barely broken a sweat during the first mile. I had started further back in the pack at the starting line, setting myself up around ~9 minute mile or so runners. To be honest, I was a little worried I might have a negative GI experience during the run and need to bail into the woods, emerge 1 sock shy of a pair – you get where I’m going with this. At the start, the strollers were basically right behind me. But then as the race played out, I was passing plenty of runners, and feeling easy, breezy, beautiful, covergirl.

In fact, the frustrating thing about this run was that at the end I saw my finish time was pretty dang close to my November 5K test, and that the race day course had more elevation, and I’d been sick. So by all accounts I should have been worse-off. Now, at the finish line, I was left with a major feeling that I had left some time out on the course and I could have easily shaved a minute or more off of this run.

Numbers all in one place:

DateTimeAverage Heart RateMax Heart Rate
3.25.202324:23 (1.8% slower)142 (21% improvement)158 (15% improvement)


I’m attributing the improved RPE, feeling, and average heart rate numbers at the 2nd run to all of the ruck training I had done in between. The months before the November 5K test did not have as much rucking/cardio endurance type work in them, though I was working out and doing some runs. In hindsight, they were too fast – I don’t know that I did a single “zone 2 specific” run in the period leading up to the 11/25/22 test.

So: you’re probably running or doing your cardio days too hard, and some very productive training will happen in sessions that don’t FEEL “hard” enough to be productive at all. It’s a “trust the process” type of thing, and definitely something that I had overlooked in my prior training. As best I can explain it, it seems that the Zone 2 work sort of recalibrated the cardio gauge of what is “easy” and thus made me faster at the same perceived effort – or (6 of one, half dozen of another), made that same speed/pace feel a lot easier to achieve and maintain. I plan to continue testing this out, but it would seem that max efforts are going to be a lot faster moving forward.

Special thanks to PATHFINDER Ruck Training for the community and programming library. Learn more about their ruck-based fitness training at their website:

Have any thoughts? Put them in a comment below or email them to me:


Gear Review: Ten Thousand Tactical Short

I first came into contact with the Interval Short from Ten Thousand, which is a premium apparel brand that makes a variety of different workout apparel. Kevin over at @dadbod_wod did a giveaway during the early COVID-lockdown-era and I was lucky enough to win a pair of these shorts. Micro review on those: I like them! They made me believe that a pair of workout shorts could be “worth” more than $70 USD and led me to explore the other offerings from the company.

Enter: The Tactical Short from Ten Thousand. Their site touts a lengthy review and testing process using input from tactical professionals, i.e. military dudes who ruck a lot. I am not a tactical military dude. But I ruck a decent amount, so I decided to pick up a pair of the Tactical Shorts that were on clearance (solely for the cardinal sin of being an ugly/undesirable color, as best I can tell) and try them out. They have quickly become my favorite shorts.

Coincidentally as of this writing, it has been almost exactly 1 year that I have owned the Tactical Short (liner, 5 inch inseam flavor) from Ten Thousand. I would say in that year I have worn the shorts at least weekly for some sort of exercise, race, ruck, or other use. Thoughts for several of these use cases are below. Don’t feel like reading? Go buy a pair and you’ll be glad you did. Do feel like reading? Here you go:

Workouts: The shorts perform well and the durability has been good. My garage gym flooring is mostly poured concrete, so it can be somewhat abrasive on fabrics. There is minimal pilling on the outer fabric layer. The one thing that did “break down” on the shorts was the end piece on the drawstrings has slipped off. But since I tie them off and tuck the strings down into the waistband, they’re not visible and it’s not about looks anyway. The 5″ inseam length is great for all the workouts I’ve used them for – the shorts feel lightweight and out of the way for range of motion with hip- and leg-focused movements like squats and lunges. The original pair of Interval shorts I got from @dadbod_wod are 9″ inseam length and while they’re great for rucks/runs, they do feel a little “in the way” on some PT movements.

Rucking: Outstanding performance for rucking in a variety of temperatures and conditions: 90+ degree F summer weather, cool spring mornings, everything in between. Having the liner in the shorts prevents chafing in all but the hottest/longest sessions and the fabric dries quickly when you sweat. If you wanted to combine the features of these shorts with compression, I’d recommend sizing down and the liner can serve as a compression layer for your quads. It’s nice that a pair of shorts in this length has pockets, too (zippered!), to hold the phone or house key while you walk. Based on the durability I’ve seen out of the fabrics used in these shorts, I would also say they should be great for an official GORUCK event or similar activity (but I don’t know for absolute certain because the company decided to stop putting on events in my area…)

Running: Outstanding performance for running too. I am a relatively sweaty person during runs and especially in the summertime – and similarly to the note in the ruck section above, these shorts are great for running in hot weather too. If I’m doing anything more than a 2 mile run I will necessitate the Tactical Short because that is the length of run at which the thigh chafe begins to occur for me as a member of the #ThiccBoyRunningClub. (2 miles and under? SOFFE silkies all the way, baby – sky’s out, thighs out.) I wore them for a Half Marathon in Spring 2022 and they were great, literally zero issues with any chafe, fabric riding up, etc. – and it even rained a little during the race too.

Conclusion: I strongly recommend the Tactical Short from Ten Thousand as an all-around awesome piece of workout apparel. If you’re looking to expand the wardrobe by multiple pieces, they have a 3-pack deal which gives a discount, so that might be up your alley too. GORUCK has also recently collaborated with Ten Thousand on a co-branded version, which looks like an identical product with a GORUCK logo added:

If anyone at GORUCK and/or Ten Thousand would like to send me a pair to review, my DMs are open.

Thoughts? Agree? Disagree? Let me know with an email:


Having lost the login for the previous iteration of this blog (which is still apparently available at, I have regrouped here and am going to put some writings up when I have a strong opinion on something related to:

  • Fitness, training, and lifestyle stuff: trying to be a good, strong dad
  • Gear and product reviews for stuff I’ve used
  • Leadership, work and experiences as a first responder
  • Book reviews
  • Adventures, challenges, and events

I’m hoping for this to become an extension of my social media presence and a place where people might be able to learn something, get inspired, or better themselves in some way. The past few years have been profoundly influential in the course of my life – for the better – and I hope to help others as I have been helped by some of the great online resources I have used.

Have a comment? Looking to share or repost something, or get something written? Contact me at


PS: From time to time you may see an affiliate link for certain products. You get my unfiltered opinion on the gear linked – good, bad, all of it. You click and buy? I get a tiny cut.